Emergency responder safety

Keep your distance from electricity.

Electricity is a powerful force. Contacting it is extremely dangerous and can lead to serious injury or death. Even low-voltage electricity poses this danger.

Your best protection from electricity is distance. Stay as far away as possible from power lines and other electrical equipment, and keep tools, equipment and vehicles away as well.

Remember, all safety clearances given on this site are minimums. Always keep the maximum possible distance between you and any electrical equipment.

Visualizing electricity

Everything around us is made of tiny particles called atoms. In the center of an atom is its nucleus. Smaller particles called electrons orbit the nucleus. When the negatively charged electrons move between atoms, this creates electricity. Electricity is energy caused by the movement of electrons.

Most of the electricity we use in our homes and businesses comes from power plants. Power plants use various energy sources to spin large turbines, which in turn spin electromagnets with heavy copper wire surrounding them. The electromagnets’ motion forces the electrons in the wire to jump between atoms, causing electricity to flow through the wire.

Electrical terms

Voltage: the force that causes electrons to move. It is measured in volts. (If electrical equipment, such as a power line, transmits more than 600 volts of electricity, it is classified as high-voltage.)

Current: the amount of flowing electricity. It is measured in amperes, or amps for short.

Resistance: opposition to electric current. It is measured in ohms.

Voltage, current, and resistance are all related. A high-resistance material, for instance, will require a greater voltage to transmit the same amount of electricity as a lower-resistance material. Because of this, if your body’s resistance to electricity is decreased, you can be shocked more easily. One example is when your skin is wet or you stand in water. Since water conducts electricity very well, having wet skin will lower your resistance and make it easier for you to get shocked (even with a low-voltage current).

Visualize a stream of water flowing through a hose. Voltage, which measures the force of electricity, is like the water pressure. Current is like the water flow rate, and resistance is like the friction loss that occurs at the nozzle or at a valve that limits the water flow.

Grounding

Electricity always seeks to equalize between areas of high and low voltage. Because the earth is at zero voltage, this means electricity will always seek the ground. When electricity flows to the ground, this is known as grounding.

If electricity is given a path, it will always move from a high-voltage source to a low-voltage area until the voltage equalizes. This is why, during a storm, lightning tends to strike the tallest conductive object around. Lightning is simply the voltage equalization of the sky and the ground through the easiest path available.

Conductors and insulators

Conductors: materials that conduct electricity well. These materials have atoms with loosely bound electrons, so the electrons are free to jump from atom to atom and form a current. Common conductors include water and many types of metal, such as copper, aluminum and steel. The human body is mostly water, which means you are an excellent conductor and, therefore, vulnerable to electrical current.

Insulators: materials with a high resistance to electricity. These materials have atoms with tightly bound electrons, so the electrons are less likely to jump around and form a current. Common insulators include plastic, rubber, ceramics and fiberglass.

Anything can be a conductor—even a typically insulative material—at a high enough voltage or in just the right conditions. Watch out for conditions that may reduce resistance. Always be alert for potential paths to ground, and keep yourself, as well as tools and equipment, far away from them.

Arcing

Arcing: the act of electricity flowing through the air. This occurs at high voltages. An electrical arc can burn your skin and eyes, which is why you should stay far away from high-voltage power lines.

Touch potential

If any conductive object becomes electrically energized, it can create touch potential, which is the voltage difference between any energized object and the feet of a person in contact with it. Examples of this danger include downed power lines and short circuits in wires or appliances.

If you touch an energized object, your body will become the path for electricity to flow to the ground. The greater the voltage difference, the higher the touch potential and the more electricity will flow through your body.

Electricity always flows from high- to low-voltage areas until the voltage is equalized. Two areas of differing voltage have the potential for electricity to flow between them. Electrical potential refers to the difference in voltage between the two areas. If there is no voltage difference, there is no electrical potential and electricity will not flow.

Step potential

Similar to touch potential is step potential: the voltage difference between the two feet of a person standing near an energized, grounded object.

When an energized object, such as a downed power line, contacts the ground, electrical current will flow into the ground. At high enough voltages, the electricity spreads out in concentric circles from the point of contact. This is referred to as a voltage gradient because the voltage is highest at the point of contact and decreases with distance outward.

If you step across a voltage gradient, you could be electrocuted. One foot will have a higher voltage than the other, and electricity will use your legs as a path to equalize it. Similarly, step potential can affect two people carrying a long conductive object, such as a metal ladder. Electricity can flow up one person’s legs, through the object, and down the other person’s legs, causing serious injury to both.

Avoid touch and step potential

To avoid touch potential, never touch anyone or anything that may be in contact with a source of electricity. If you do, you will become a victim as well. Wait until the electricity is turned off before attempting a rescue.

Do not touch downed power lines or anything they are touching, which may include:

• Phone or cable lines
• Utility poles
• Vehicles
• Metal fences
• Ladders
• Trees
• The ground

To avoid step potential near an energized, grounded object, shuffle away with small steps, keeping your feet close together and on the ground at all times. Keeping your feet together ensures that the voltage remains the same between them, minimizing the electrical potential.

Shock effects

Electrical shock can cause a variety of injuries. The most serious is cardiac arrest, but there are also many less obvious effects you should watch for.

The effects of electrical shock increase in severity as the current increases. This chart shows the effects of electricity as the current increases by milliamps. A milliamp is 1/1000 of an amp.

• 5 milliamps can cause mild shock and pain.
• 50 milliamps (approximately the current inside a 7.5-watt holiday light) can cause severe pain and muscle spasms. These spasms make it hard to move away from the source of electricity, furthering the danger. Contacting this amount of current may even be fatal.
• 100 milliamps (approximately the current inside a 12-watt electric razor) can cause respiratory arrest, burns (internal and external), and tissue destruction. Direct contact with this amount of current is almost certainly fatal.

As you can tell from these examples, it doesn’t take a lot of electricity to injure or even kill!

Use this section to better understand how electricity travels to homes and other structures. You will become familiar with some of the equipment used in electricity transmission and distribution, as well as the hazards associated with these facilities.

Power plants

Generation facilities or power plants are the first step in the electrical distribution system. Power plants use fuel, such as oil or natural gas, to heat water into steam. The pressurized steam spins large turbines, which in turn spin electromagnets with heavy copper wire surrounding them. The electromagnets’ motion forces the electrons in the wire to jump between atoms, creating electricity that flows out to power our homes and businesses.

Solar power plants and wind farms are other types of generation facilities. At a solar plant, large arrays of photovoltaic panels convert sunlight into electricity. At wind farms, large groups of turbines spun by the force of the wind are used to generate electricity.

Switchyards

A switchyard transmits electricity from a power plant into large transmission lines. Just as railroad switchyards direct trains onto the right tracks, electric switchyards direct electricity onto the right transmission lines for distribution.

Switchyard equipment is extremely dangerous. Switchyards are filled with transformers, circuit breakers, switches and other high-voltage equipment. Here, electricity is raised to very high voltages in order to be moved efficiently across great distances. The high-voltage equipment poses many dangers, including electrocution, explosions and release of oil.

Transmission lines

High-voltage transmission lines carry electricity from switchyards to local power grids, substations and other facilities. Transmission lines are designed to carry high voltages in order to minimize the energy loss that naturally occurs over long distances. Most of these lines span between tall transmission towers, while a small number are underground.

Overhead transmission lines are not insulated, and contacting them is dangerous. The coating on power lines is designed for protection from the weather and will not prevent electrical shock. Even approaching the lines with aerial equipment or extinguishing agents can cause electrical arcing. This is why transmission line emergencies require large safety clearances, as well as unique response tactics.

Substations

Substations receive electricity from transmission lines and lower its voltage for local distribution. The equipment in these fenced-in facilities poses significant hazards to first responders.

Oil-filled transformers serve to cool and insulate internal components. If there is a fire, the oil can explode, spill and/or produce hazardous smoke. Any substation fire should be treated as a hazardous materials response.

Circuit breakers automatically test and re-energize circuits multiple times. Even if a circuit fails, it could potentially become live again due to the activity of automatic circuit breakers. For safety’s sake, always assume that substation equipment is energized.

Control buildings house equipment for controlling and monitoring substation batteries in addition to other equipment. Never enter a control building unless you have the assistance of qualified personnel.

Distribution lines

Distribution lines carry electricity from substations to customers. Some distribution lines are located underground, but the majority are found on overhead poles. The poles are made of metal, fiberglass or a special wood that is chemically treated to prevent rotting. The chemicals in this wood can pose a toxic smoke hazard in the event of a fire.

Distribution lines may appear insulated, but their coating is designed for protection from the weather and will not prevent electrical shock. Always assume these lines are energized and dangerous, and keep yourself and your equipment at least 20 feet away—and much farther away whenever possible. Always use the maximum possible distance.

Primary and secondary lines

Primary lines, or primaries, are higher-voltage lines located at the top of utility poles, above transformers. Primaries are usually made out of copper or steel encased in highly conductive aluminum. Typical primary voltages range from 12.5 to 34.5 kV.

Secondary lines, or secondaries, are located lower down on utility poles, usually below transformers. Typical secondary voltages are between 120 and 480 volts. Although the voltage is lower, these lines can still deliver a severe electrical shock if contacted.

Insulators, transformers and regulators

Insulators connect the power lines to the utility pole and ensure that electricity remains in the lines. They are made of insulating materials, such as porcelain, glass or nonconductive polymers. Insulators are there to prevent electricity from escaping and traveling down the utility pole.

Step-down transformers serve to reduce the electricity from primary lines to a voltage more suited for customer use. These transformers are bucket-shaped and can be found between the primary and secondary lines.

Regulators are special transformers that maintain specific voltage levels. They are generally rectangular.

Both transformers and regulators cool their internal components using oil, which can pose explosion, smoke and oil-release hazards. In the event of a fire, be aware of this danger.

Other distribution line fixtures

Automatic reclosers, found on both transmission and distribution lines, are programmed to re-energize dead power lines multiple times. Just like the circuit breakers in a substation, reclosers can cause a dead line to become live again. This is why you should always assume that all lines are energized (even fallen or low-hanging lines that may appear dead) unless you are otherwise notified.

Guy wires are cables that support utility poles against wind and weather. If a utility pole is damaged or if power lines sag low enough, guy wires can potentially become energized and pose an electrical shock risk.

Underground lines

Underground distribution lines may run through metal or plastic conduits or may be buried directly in the earth.

Contacting any underground power line poses a shock hazard as well as the possibility of power outages. Anyone doing a digging project is required by law to notify the 811 center well in advance of digging by dialing 811 or placing an online request. The 811 center arranges for the location of nearby underground power lines to be marked so that digging can take place a safe distance away from them.

Pad-mounted transformers

Pad-mounted transformers, also known as ground transformers, function as transformers for underground power lines. Just like their overhead counterparts, they lower the voltage of electricity to appropriate levels for use in structures. These transformers carry large amounts of electrical current and contain oil used for internal cooling, so exercise caution around them.

An underground service wire runs from a buried distribution line or pad-mounted transformer to a customer’s meter. Like underground power lines, these wires may either be direct buried or run through a metal or plastic conduit.

Underground vaults

Underground vaults sometime serve areas with underground distribution lines. These vaults are generally located in urban areas. They contain much of the equipment found on overhead utility poles, including power lines, transformers, regulators and switches.

Overheated or burning electric cables in an underground vault can produce highly reactive gases, such as hydrogen, acetylene and ethylene. The gases may contain elevated concentrations of carbon monoxide and may be toxic and combustible. This is why even a small fire in an underground vault can create an atmosphere immediately dangerous to life and health (IDLH).

Service wires and weatherheads

An overhead service wire runs from a distribution line or transformer to a weatherhead on the roof or side of a structure. The service wire may appear as a single wire or as three wires twisted together. A hollow steel tube called a service mast carries the service wires from the weatherhead to the meter.

A weatherhead is a waterproof hood that protects service wires as they enter a building. Other names for this apparatus include weather cap, service head or service entrance cap. One side of a weatherhead slopes down to allow moisture to flow away from the connection. It also contains watertight rubberized gaskets that protect the wires as they pass under the hood and into the service mast.

Overhead service wires should always be treated as energized and dangerous to contact. Like power lines, these wires are coated for protection against the elements and not for insulation against electrical shock.

Service panels

Customer meters measure the amount of electricity used in a structure. They are typically found on the outside of a building or inside an external wall.

Service wires pass through the meter and then connect to a service panel, which directs electricity into individual circuits that serve different areas of the structure. Each of these circuits has a fuse or circuit breaker, which will cut the power if there is a short circuit or electric overload. Circuits in residential structures usually carry 120 or 240 volts, while circuits in industrial buildings may carry up to 10,000 volts.

First responders should never attempt to disconnect an electric meter. Doing so can create a deadly electrical arc.

Use this section to learn about response tactics for fires that involve electric substations, transmission lines, distribution lines and vaults plus tips for protecting yourself from electrical contact when fighting structure fires. This section also covers some of the exposure risks and environmental hazards associated with electrical facilities.

Arriving on the scene

When you arrive at the scene of a fire involving electrical equipment, be sure your dispatcher has notified Colorado Springs Utilities. Work with them in a unified command structure, and follow these precautions:

• Approach the scene cautiously after surveying from a safe distance. Look for electrical hazards, such as leaning utility poles and downed power lines. Mark any hazards with cones or barrier tape.
• Consider all wires and equipment energized and dangerous (regardless of their size, type and insulation) unless you are otherwise notified.
• Keep all personnel and equipment at least 20 feet away from overhead power lines carrying up to 50 kV and farther away for higher voltages. Confirm line voltages and safety clearances with Colorado Springs Utilities.
• Keep in mind that wind can move lines and equipment. Use a spotter to help you maintain the maximum possible clearance.

Protecting the public

Secure the area to keep the public away until Colorado Springs Utilities personnel tell you it is safe. Reroute traffic, and establish a safety perimeter to keep the affected area off-limits.

If there are transformers or circuit breakers involved in the situation, be alert for explosions, smoke hazards and oil releases. If an oil release occurs, follow your department’s evacuation guidelines for a hazardous materials response.

Safeguards

The following safeguards apply whenever you arrive at a fire that involves electrical power lines, substations or other electric equipment:

• Always wear full personal protective equipment (PPE) and self-contained breathing apparatus (SCBA).
• Identify any overhead power lines before extending ladders and aerial equipment. Designate a spotter to make sure you maintain safe clearances.
• Confirm the interruption and restoration of electric service with Colorado Springs Utilities.

Remember the 50/30/100 rule when protecting exposures during fires that involve electrical equipment: Stay at least 50 feet away from energized objects, and use a 30-degree fog pattern at 100 psi, NEVER a straight stream.

What NOT to do

There are four things you must NOT do when you respond to a fire that involves electrical equipment:

• Do NOT stand on the ground when operating aerial equipment. Staying on the equipment will keep you safe from electrical shock in the event an extension boom contacts a power line.
• Do NOT work in areas where smoke is dense. Dense smoke can obscure electrical hazards, such as downed power lines. It can also conduct electricity.
• Do NOT use water to suppress the fire unless directed to do so. Instead, use a dry chemical extinguishing agent.
• Do NOT use a solid stream of water to protect exposures. A solid water stream can conduct electricity or cause insulators to shatter.

Substation fires

If a substation or transformer is burning, immediately contact Colorado Springs Utilities, and wait for their personnel to arrive. Do NOT enter the substation. While you wait, take a defensive approach, and follow these steps:

• Let the fire burn unless or until otherwise instructed by utility personnel. Burning electrical equipment is already ruined and will not be repaired. Do not risk injury to protect it as it will be replaced anyway.
• Isolate the area with a radius of at least 330 feet. Keep anyone unauthorized away from the area.
• Be alert to explosion and toxic-smoke hazards. Stay upwind and consider initial downwind evacuation for at least 1,000 feet.
• Follow the 50/30/100 rule: Stay 50 feet away from energized objects, and use a 30-degree fog spray at 100 psi to protect exposures and prevent fire from spreading.
• Monitor for oil runoff. Direct any oil away from catch basins and surface waters.

Extinguishing substation fires

Never enter a substation unless specifically directed to do so by your incident commander. If you have been told to suppress the fire, take the following precautions:

• Position emergency vehicles at least 30 feet away from any overhead power lines.
• Use only nonconductive ladders. Do not use metal ladders.
• Carry ladders parallel to the ground. This helps you avoid contacting overhead facilities.
• Never enter a substation until utility personnel have confirmed that the equipment is de-energized.
• Never use a solid stream of water on an oil fire; always use a fog stream. Transformer oil fires can be extinguished with protein foam sprays and water fog sprays, but a solid stream of water can actually spread an oil fire.
• Report all oil releases to the incident commander. Follow standard tactics for a hazardous materials response.

Transmission line fires

Fires around high-voltage transmission lines require special precautions. Fire, smoke and even heat can act as conductors and cause electrical arcs from transmission lines to the ground. Avoid the dangers of step potential by maintaining appropriate safety clearances:

• If the flames are 100 feet or farther from energized overhead transmission lines, keep all personnel and equipment at least 50 feet away.
• If there are flames within 100 feet of energized overhead transmission lines, stay at least 330 feet away.

If you are instructed to protect exposures near a transmission line using water, use a 30-degree fog pattern with at least 100 psi of pressure. Never use a solid stream.

Distribution line fires

Burning utility poles may cause downed power lines. Follow these precautions:

• If possible, de-energize lines before extinguishing a pole fire. Only apply extinguishing agents to an energized pole under your incident commander’s direction. These agents may include dry chemical or water fog spray using the 50/30/100 rule.
• Do not use water around a utility pole unless the incident commander directs you to do so.
• If transformers are burning, be alert for explosions, smoke hazards and oil releases. Even when the fire is put out, there may still be oil present and power lines may still be energized.
• Create a safety perimeter, and keep bystanders at least 50 feet away. Maintain this perimeter until utility personnel confirm that the lines are de-energized and oil cleanup is complete.

Vault and manhole emergencies

If smoke or flames are coming out of a manhole or vault, take the following precautions:

• Establish a safe perimeter, reroute traffic and notify utility personnel.
• Never park over a manhole cover. An underground explosion can propel a manhole cover high into the air and cause extensive damage.
• If no one is inside, stay out and let the equipment burn. Unless there is a victim in danger or your incident commander instructs you otherwise, let it burn, and do not enter.
• Even a small fire in a vault can create an atmosphere immediately dangerous to life and health. Make sure to test the air for hazards, such as flammable and toxic gases. Assess the potential for gas migration, then isolate and evacuate affected areas, and eliminate spark hazards.
• Do NOT open vaults or remove manhole covers. Doing so may make an already flammable atmosphere become explosive by adding oxygen to it. In addition, manhole covers can be charged with electrical voltage.

If a victim or downed responder is trapped in a manhole or vault and you must assist them, do not enter until the electric utility confirms that all underground equipment is de-energized. When you enter, wear full PPE and SCBA, and follow your department’s safety procedures for confined space entry and rescue.

Structure fires

Fighting a structure fire means you will likely be exposed to energized electric wiring and power lines. Service to residential structures is usually low-voltage, while industrial service can reach 10 kV. Regardless of the voltage, you must avoid contact with electricity when you approach, de-energize and enter a structure.

Approaching a structure

When approaching a structure fire, take these precautions to prevent contact with overhead power lines, service wires and energized objects:

• Keep yourself and your tools and equipment at least 20 feet away from ALL overhead power lines, including service wires, which run from utility poles to buildings. (Service wires are NOT insulated; any coating on them is not insulation.)
• Have a spotter monitor the placement of ladders and aerial equipment to maintain the maximum possible clearances from all power lines.
• Be alert for sagging lines. Fallen or sagging service wires can energize gutters, fences and other conductive objects.
• Keep yourself and any aluminum ladders clear of metal awnings, rain gutters and aluminum siding. Fire may compromise electric wiring inside walls, energizing metallic objects.

Weatherheads

Keep hose streams away from the underside of weatherheads. The gasket on the underside of a weatherhead may have fine cracks that will keep out moisture from the top and sides but yield to water under pressure from a hose stream.

Watch out for damaged weatherheads. Weatherheads are designed to resist wind, rain and snow, but they can still be damaged by impact from solid objects.

Be careful around service masts. If you slip and fall against a service mast, you could pull wires loose and risk electrical shock.

De-energizing and entering

Consider all wires, machines and appliances inside a structure potentially energized, and stay away, even if you believe the power is off. There may be other sources of electricity in use, such as backup generators or solar batteries.

Do not pull a meter or disconnect a service wire on a potentially energized structure. This is extremely dangerous and could get you shocked. Turn off power using the main switch only if you are trained to do this and the utility has confirmed that it is safe.

Keep your palms turned inward when entering any structure. If you contact an energized wire, muscle spasms may cause your arms to contract; with palms facing inward, your arms and hands will pull away from the source of electricity. (Be aware that turning your palms inward will not protect you in the event of a high-voltage shock.)

Asbestos and lead awareness

Asbestos and lead are two hazardous substances that may be present in electrical equipment. Asbestos may be found in breakers, panels, cable conduits and wraps. Lead may be found in some wire and cable coatings.

Exposure to lead or asbestos can cause serious health problems. Asbestos fibers may attach themselves to clothing, which puts coworkers, friends and family at risk. Inhaling asbestos may cause chronic lung disease or cancer. Lead particles may be inhaled from combustion gases or even absorbed into the skin if directly contacted and can damage organs, muscles and bones.

These substances are not easily detected, so you must assume that all electrical equipment and coatings contain them.

Asbestos and lead precautions

Combine your department’s specific safety guidelines for asbestos and lead exposure with the following general precautions:

• Wear full PPE and SCBA whenever you respond to a fire involving electrical equipment.
• Avoid touching or spreading any dislodged coating materials. Keep these materials isolated from the public, and set up barriers to prevent tracking them around.
• Inform your incident commander and utility representative if you have touched anything that you suspect may contain asbestos. Stand by for decontamination if needed.
• Do not attempt cleanup yourself. Trained asbestos specialists must come to collect and properly dispose of these materials.

Oil release precautions

If a transformer or other electrical equipment overheats or gets damaged, it may release oil. All oil releases must be treated as environmental hazards and immediately reported to your incident commander as well as to Colorado Springs Utilities. Take the following precautions to protect yourself and the public from oil releases:

• Wear proper PPE around oil spills. Follow standard tactics for hazardous chemical releases. Keep personnel and the public away from the oil until the utility representative confirms that the area is safe.
• Avoid spreading the oil; do not walk, drive or drag hoses through oil spills. Use absorbent and containment materials to prevent the oil from spreading.
• Prevent the contamination of water resources. Limit or direct water spray and fire suppression materials in order to avoid spreading oil. Keep oil away from manholes, wetlands, catch basins and all bodies of water.

PCB hazards

Polychlorinated biphenyls, or PCBs, are a probable carcinogen that may be found in transformer oil. PCBs were widely used for cooling electric capacitors and transformers until the EPA banned them from most uses in 1979. A yellow warning label is required on certain equipment that contains PCBs at a concentration of at least 500 ppm. However, at low concentrations or with specific types of equipment, this label may not be required. Therefore, you cannot assume that PCBs are not present just because there is no label.

Assume that all oil releases from electrical equipment contain PCBs, address these incidents as hazardous chemical releases and follow your department’s hazardous materials safety precautions.

Use this section to learn the dangers of downed power lines and how to keep yourself and the public safe around them. It includes response tips for vehicle-utility pole contacts and explains what to do if your aerial equipment contacts a power line.

Downed power line hazards

All downed power lines pose a shock hazard. Downed lines can shock you even if they do not hum or spark. They can also energize the ground nearby and create a step potential zone. Even dead lines can become re-energized at any time due to automatic reclosers.

If you know or even suspect that a power line is down, contact Colorado Springs Utilities immediately, and take precautions to protect yourself and the public.

Parking tips

Park on the opposite side of the street from involved utility poles.

Park at least one full span away from the downed power line. A span is the distance between two utility poles.

Approaching downed lines

As you approach a downed power line, look for the ends of the line. They may be hidden by objects or foliage. Downed lines may energize objects, so also look for anything they may be in contact with, such as fences, vehicles, trees, utility poles and other wires.

Be alert for multiple hazards. If there is one power line down, there may be others. Don’t let the most obvious hazard distract you from other potential hazards in the area.

Watch out for downed lines contacting metal fences. If a downed power line energizes a metal fence, the fence can conduct that electricity a long way from the incident scene.

Coil memory

Power lines have a property called coil memory. This refers to a situation when a downed line is pinned underneath an object. When released, the line tends to recoil back toward the place where it is connected.

If you see a pinned line, note the path it may take if it is released, and stay away.

Securing the area

Maintain a safety perimeter around downed power lines until you receive the all-clear from utility personnel.

Keep yourself, vehicles and equipment at least 50 feet away from downed distribution lines and at least 100 feet away from downed transmission lines. All safety clearances given here are minimums; always use the maximum possible distance.

Keep the public at least one span away from the downed line by establishing an exclusion zone.

Vehicles contacting utility poles: No imminent danger

In a situation where a vehicle has contacted a utility pole and there is no imminent danger, do the following:

• Keep yourself and others far away from the vehicle, the power line and anything the power line is touching—including the ground nearby. Anyone who enters, touches or even approaches the vehicle could be shocked.
• Instruct the driver to drive away from the power line if they can do so safely. Have them drive at least 50 feet away from a distribution line or 100 feet from a transmission line before exiting the vehicle.
• If the vehicle cannot be safely moved and there is no imminent danger, instruct vehicle occupants to stay put until utility crews give the all-clear. Occupants will be safest from electrical shock inside the vehicle.
• Do not allow occupants to leave the vehicle until the utility representative confirms that the line has been de-energized.

Vehicles contacting utility poles: Imminent danger

If a vehicle has contacted a utility pole, there is imminent danger such as a fire, and occupants must exit the vehicle, instruct them on using the jump and shuffle technique. Explain and demonstrate the steps from a safe distance:

• Do not step out of the vehicle, and do not touch the vehicle and the ground at the same time.
• Jump clear of the vehicle, landing with feet together.
• Shuffle away with small steps, keeping your feet close together and on the ground at all times.
• Continue shuffling to a safe distance away. A safe distance is at least 50 feet from distribution lines or at least 100 feet from transmission lines. Remember, all safety clearances given here are minimums. Always use the maximum possible distance.

Aerial equipment contact: No imminent danger

If your aerial equipment comes into contact with a power line and there is no fire or other imminent danger, take the following steps:

• Stay on the vehicle.
• Call Colorado Springs Utilities.
• Warn others away. People on the ground are in the greatest danger when equipment hits a line.
• Move the equipment away from the line if it is safe to do so.
• If you cannot safely move the equipment, stay put until the line is de-energized.

Aerial equipment contact: Imminent danger

If your aerial equipment comes into contact with a power line and there is fire or other imminent danger, use the jump and shuffle technique:

• Do not step out of the vehicle and do not touch the vehicle and the ground at the same time. Because of touch potential, you could become electricity’s path to ground and get fatally shocked if you touch both.
• Jump clear of the vehicle, landing with your feet together.
• Shuffle away with small steps, keeping your feet close together and on the ground at all times. Do not run or take large steps. Because of step potential, you could be fatally shocked if your legs bridge two areas of differing voltage.
• Continue shuffling to a safe distance away. A safe distance is at least 50 feet from distribution lines or at least 100 feet from transmission lines. Remember, all safety clearances given here are minimums. Always use the maximum possible distance.

As solar photovoltaic (or “PV”) power becomes more prevalent in the U.S., it is increasingly likely that you will respond to an emergency involving a solar PV system. Use the menu on the left to learn how solar PV systems work and the risks they pose to first responders.

What is solar power?

The sun is a tremendous source of energy. If we could capture all of the solar energy that the Earth’s atmosphere receives in one hour, it could power the electricity needs of every living human being for a year! Since this energy is clean, renewable and extremely abundant, it’s no surprise that solar power is growing in popularity.

When you think of solar power, you probably picture a solar panel. A solar panel is one component of a solar PV system, which is the most common method of harnessing solar power. Solar PV systems can be configured for a variety of uses:

• Solar PV systems can be connected to dedicated storage batteries and/or to the power grid. The majority of systems nowadays are connected to the grid, enabling excess power to be shared with others.
• Solar PV systems range in scale from a single solar panel on the roof of a house to a commercial array spanning multiple acres. Some are easy to spot, but others may not be as obvious.

It’s likely that solar PV systems exist in your response area or in neighboring jurisdictions, so it is important to learn how to recognize them.

Variation in solar PV systems

Unfortunately, there is no universal standard for all solar PV systems. Here are some common variations in the ways they are set up:

• Commercial versus residential systems: Both types generally use the same components, but commercial systems produce more energy at higher voltages, and they may contain additional components such as step-up transformers. However, remember that residential systems still pose an equal risk of electrocution.
• Control systems: Some solar PV systems are controlled from a single point, while some have multiple shutoff switches. Commercial systems, due to their larger sizes, tend to have more complex controls. Not every system can be controlled in the same way.
• Code compliance: Some systems may not be entirely code-compliant, particularly if someone inexperienced installed them. And since local building codes can vary, even a technically code-compliant system may not have the same safety features as another system in a different location.

Each solar PV system can vary considerably in appearance, which is why it is crucial to become familiar with all the features and components of solar PV systems, and to remain alert when dealing with one.

There is one universal rule when responding to an emergency involving a solar PV system: ALWAYS assume that all PV components are energized. Even if it is dark, the panels are covered or the system is powered down, voltage remains inside. To stay safe, treat the whole system as if it is energized at all times.

Solar PV hazard awareness

Solar PV systems look deceptively harmless and the amount of power contained inside is not always obvious. Even a small PV system can generate enough electricity to injure or even kill. All solar PV systems pose the same danger.

Solar PV arrays do not need direct sunlight in order to produce electricity. They can be activated by other light sources, including fire, scene lighting, moonlight and even flashlights. And even if a panel is shattered or otherwise damaged, its components still pose a shock hazard. Never assume that a solar PV system is inactive or harmless, and always exercise extreme caution around them.

Roof-mounted solar PV systems

Roof-mounted solar PV systems commonly use solar PV panels that are often arranged in sets, collectively called arrays. There are also special types of roof tiles and shingles with integrated solar PV technology, so you might not immediately recognize a roof-mounted system if it uses these rather than traditional solar panels. The solar panels or other solar PV materials absorb sunlight and turn it into power in the form of direct current (DC), which must be converted into alternating current (AC) before it is ready to run lights, appliances and devices within a traditional 120-volt AC system.

Ground-mounted solar PV systems

Roof-mounted solar PV systems can be impractical for some people (such as homeowners whose roofs don’t get optimal sun exposure or renters who can’t modify their roofs). This is where ground-mounted solar PV systems come in. As the name suggests, rather than being mounted on a roof, ground-mounted solar PV systems are located at ground level.  

Free from the space and weight limitations of roofs, ground-mounted solar PV systems can be larger and more complex than roof-mounted systems. Some of them even use motors or hydraulics to adjust the angle of the solar panels, following the sun throughout the day to catch as much sunlight as possible. “Solar gardens” consist of ground-mounted solar PV arrays that are shared by residents of a neighborhood or used by farmers to supplement their income. Ground-mounted solar PV systems can also be found in public spaces, such as along highways.

Grid-tied solar PV systems

Most solar PV systems today are grid-tied (also known as grid-connected). This means that the surplus electricity these systems create can be directed into the larger electrical grid. Grid-tied systems contain a utility meter through which the current must flow to reach the grid. The current first passes through an inverter, which converts DC into AC. Then any AC current that is not used locally goes into the grid through the meter.

Current industry standards require every grid-tied system to have a safety feature that shuts the system down to prevent it from backfeeding into the grid if nearby circuits lose power.

Off-grid solar PV systems

Off-grid solar PV systems are less common. These systems, also known as stand-alone, have a battery bank to store their surplus power for use when the system is not generating electricity. The power is stored in the form of DC. The inverter converts it to AC on its way out of the batteries for use in lights, appliances and equipment.

Hybrid solar PV Systems

A growing number of solar PV systems combine multiple functions. These hybrid systems may include electric vehicle (EV) charging, standby battery power and grid-tied components. They utilize grid-tied inverters to move electricity between battery banks and the utility grid. Hybrid solar PV systems are expected to become more prevalent as the technology advances, so be aware that you may encounter one.

Arrays

Solar PV cells are small squares, approximately 4 inches wide, which absorb light and convert it into electricity through a chemical reaction. Solar PV cells are arranged in sets (anywhere from 24 to 42 cells) to form modules, and modules in turn are combined to form panels. A series of panels is referred to as an array, and the entire array is securely mounted to the roof or the ground.

It might seem like solar panels are designed to withstand extreme conditions. These panels are fairly durable, but they do have their limits. They may be damaged by direct flame contact, hail or even extreme winds. But remember, even a damaged solar panel can still produce electricity.

Inverters

Every solar PV system that generates AC power contains at least one inverter, which converts DC power to AC before it can be used or fed back into the power grid.

Inverters store direct current inside capacitors. The capacitors discharge the stored electricity when inverters are de-energized, but until this process is complete, they can still deliver an electrical shock. Always treat inverters as if they contain dangerous voltage.

Industry standards require inverters to shut off within a fraction of a second if power is lost or goes out of a certain range. In this situation, the inverter will only turn back on after power has been restored for 5 continuous minutes. Be aware that home-built systems may not include this safety feature.

• Some solar PV systems, known as series grids, have all panels connected to a single inverter; if one panel in a series grid fails, it can disable the whole system.
• Other systems contain multiple microinverters, one at each panel. They are typically mounted on the back of the panels, so you may not notice them at first glance. If the system contains microinverters, use caution: even when one panel is disabled, others may still be energized.

Conduits

Electric current runs from the array to the other components of the system through conduits. These run first from the panels to a combiner box, and then to an inverter.

Next, in an off-grid system, the conduit leads from the inverter to a battery storage system. This is where the cables will enter the building, since the battery system is located indoors.

In a grid-tied system, the conduit leads from the inverter to an electric meter, passing through an AC disconnect switch in between. This switch can be used to isolate the solar PV system from the power grid.

Batteries

All off-grid systems and some newer hybrid systems contain batteries to store DC power. Always remain alert when batteries are present, since they contain both electricity and corrosive materials. Locate the battery bank – often in a garage or basement – and note the place where the conduit enters the building to connect to it.

Meters

A meter on a grid-tied system allows power to flow to the consumer or back into the grid. You can find a meter at the normal service meter location or in proximity to solar PV components. In apartments and condos, multiple meters (and inverters) may be located indoors.

Meters carry dangerous electric current and should always be considered energized, just like any other solar PV system component. Never remove an electric meter! Colorado Springs Utilities and the solar contractor are the most qualified personnel to evaluate and remove meters when necessary and to secure the system.

Labeling and signage

The National Electrical Code requires all solar PV systems to have special labeling and signage. However, the specific signage may vary based on specific local building codes, special zoning bylaws and/or city ordinances.

All systems should have operational and shutdown signage, although it may look different depending on the jurisdiction. Do not expect control and hazard identification labeling to be consistent across systems.

Check with the building owner, installation contractor or property manager to learn about specific characteristics of a single solar PV system. Ask a building department official about the signage required in your area. Solar system contractors also have expertise in this subject.

Structural risks

The following are some potential structural risks that you may face in a solar PV system incident.

• Access limitations: Solar PV equipment can block access to parts of a structure and/or impede operations. For instance, arrays may interfere with vertical ventilation. And arrays can sometimes be inhabited by stinging insects or rodents.
• Structural failure: The average solar PV array adds up to 2.5 pounds per square foot, so a 40’ by 50’ array can add about 5,000 pounds of load to the structure, often without any re-engineering of the structural carrying capacity. This increases the risks of structural failure and falling panels.
• Trip or slip hazards: Ultra-smooth solar PV-integrated roofing materials and other components can compound the risk of falling. These can reduce traction or pose a tripping hazard, especially if you are also moving quickly or in a low-visibility situation.
• Enhanced flame spread: Flames can grow at an accelerated rate near solar PV arrays, and this in turn can lead to rapid and unexpected structural failure. Extreme heat may also damage microinverters, insulation and other equipment. Solar PV panels may fall off the roof if their fasteners give way.

Electrical and chemical risks

The following are some electrical and chemical risks that you may face in a solar PV system incident.

• Shock hazards: All solar PV equipment can potentially produce voltage, even when damaged and in the absence of sunlight. Any type of light could potentially activate the system. Even a system that has been shut down is not necessarily safe. Always consider all solar PV equipment energized and dangerous. The risk of electrical shock is high in these situations, and injury or death can occur.
• Toxins and carcinogens: If solar PV equipment degrades in a fire or explosion, hazardous chemicals (such as cadmium telluride, gallium arsenide and phosphorous) may be released. These toxic and/or carcinogenic substances pose a serious inhalation hazard.
• Surges and arcing: Most solar PV system incidents involve power surges and/or arcing. This often compromises the integrity of components and insulation throughout the system, increasing the risks of electrical shock and exposure to products of combustion. Once an arc or other thermal failure occurs, all system components should be considered dangerous.
• Battery hazards: Batteries can release corrosive, toxic and flammable substances (such as hydrogen gas) if they overheat, ignite or become damaged. Of course, they also pose a shock hazard from the dangerous amounts of electricity they contain.

Review

Solar PV systems can be roof-mounted or ground-mounted. Most systems are grid-tied, while some are off-grid or a hybrid of the two.

Solar PV systems generally consist of:

• Arrays
• Inverters
• Conduit
• Combiner boxes
• Batteries
• Meters
• Disconnect switches

Potential risks of solar PV systems include:

• Access limitations
• Structural failure
• Trip or slip hazards
• Enhanced flame spread
• Shock hazards
• Toxins and carcinogens
• Surges and arcing
• Battery hazards

Always assume components are energized, even if the sun is not shining or if solar PV panels are damaged. After the system is shut off, inverters still pose a shock hazard until they have completely discharged their stored energy.

In this section, learn important precautions for emergencies involving a solar PV system, including how to perform a size-up, identify hazards, isolate the system and safely operate according to industry best practices.

Response summary

Below are the basic response tactics for an emergency involving a solar PV system. Each item will be covered in more detail throughout this module.

1. Notify Colorado Springs Utilities of the hazard and work with them in a unified command structure.
2. Conduct a 360-degree size-up of the scene to identify all system components.
3. Alert others to potential hazards.
4. Utilize full PPE, including SCBA, when working near solar PV components.
5. Maintain a safe distance from the structure and from all solar PV equipment.
6. Isolate the solar PV system.
7. Mitigate the incident.

Notify and work with Colorado Springs Utilities

As soon as you arrive at the incident scene, confirm that your dispatcher has notified Colorado Springs Utilities. In incidents that involve grid-tied solar PV systems, Colorado Springs Utilities should be viewed as a key partner and consulted throughout the response. Even with off-grid solar PV systems, Colorado Springs Utilities should still be contacted. Colorado Springs Utilities personnel can verify the lack of connection to the grid, and they can offer valuable technical advice no matter what type of system is involved. Forging a unified command structure that takes advantage of Colorado Springs Utilities’ expertise will help to ensure the best possible outcome.

Size up the scenes

A size-up is the process of gathering information when you arrive on the scene. The more information you take in at the start, the better prepared you will be to respond safely and efficiently. Even if your department is already aware of certain solar PV systems in your community and their potential hazards, pre-planning assessments should never take the place of a comprehensive size-up at the incident scene.

Perform a 360-degree size-up by walking in a circle around the structure or area involved. Take note of the layout of all sides and roofs of any structures and be on the lookout for solar PV system components that may not be immediately obvious, such as arrays, inverters and control switchgear.

In addition to physically sizing up the scene, talk to knowledgeable people like building owners, property managers and solar installers. Integrate the information they provide with the observations from your size-up to form a more comprehensive understanding.

What to look for

How do you determine whether a structure has a solar PV system? Perhaps the most obvious indication is an array of solar panels, but not all arrays are visible from the ground. Check for switchgear and/or an inverter near the electric meter, on an external wall or in a utility room. Safety signage can also alert you to the presence of a solar PV system.

During your size-up, consider the following questions about any solar PV system you encounter:

• How will it affect crew safety and operations?
• Does it include battery storage?
• How might it be affected by the incident (either now or later)?
• How can it be electrically isolated?

Communicate the hazard

Once the presence of a solar PV system is confirmed, the incident commander should notify the dispatcher, who will then sound a designated alert tone followed by a pre-scripted notification on all relevant operating frequencies. Many jurisdictions require crew leaders to acknowledge this notification. Communicating the presence of a solar PV system is essential for maximizing everyone’s safety at the incident scene.

Here is a sample notification about the presence of a solar PV system:

“Attention all personnel operating at 346 Northwest Road. A photovoltaic solar system has been identified at your location. The array is located on Side C of the structure. Be advised to use caution when operating at this incident.”

(Please note that some jurisdictions use numbers instead of letters to indicate sides of a structure. If yours follows this convention, the alert would say “Side 3” instead of “Side C.”)

Wear PPE and SCBA

Always wear full personal protective equipment (PPE) and self-contained breathing apparatus (SCBA) whenever you are around solar PV system components at an incident scene.

Your PPE will protect you from certain hazards. However, do not become overconfident, as its protection has limits. Studies conducted by Underwriters Laboratories (UL) have proven that PPE will NOT protect you from electrical shock. Other research shows that PPE may absorb some toxic and potentially carcinogenic particulates from burning solar PV panels. After the incident, make sure to fully decontaminate your gear.

Keep your distance

Voltage remains in a solar PV system even after it has been isolated from the grid by the main disconnect switch. This means the potential for shock still exists. Keep yourself and all equipment at least 3 feet away from all solar PV system components at all times. If possible, mark off the exclusion zone(s) with fire line tape or caution tape as a reminder.

While fire generally causes the most extensive damage, arcing and power surges cause the most frequent problems in solar PV system incidents. Lightning, for example, can produce a large power surge that significantly impacts a solar PV system.

Remember, your PPE will not insulate you against electrical shock. You can be shocked directly or by contacting energized equipment with your tools or ladders. This is why it is crucial not only to keep your distance but also to keep tools and equipment away as well.

Isolate the solar PV system

Even if the solar PV system is not initially impacted by the incident, it should still be electrically isolated from the grid and shut down as a preemptive measure. If the system is off-grid or hybrid, use switchgear to isolate the battery bank from both the array and the inverter. Use caution, as solar PV systems are not guaranteed to be code-compliant or to have appropriate signage, controls or safety features.

If you are involved in isolating a solar PV system, remember: Never remove an electric meter! Colorado Springs Utilities is the most qualified to secure the system. Their personnel will evaluate the meter and remove it if needed.

Once a solar PV system has been isolated, the system status should be reported to command and announced to all personnel present. Continue to maintain at least 3 feet of distance from all solar PV components and keep fire line or caution tape around them as a reminder.

Safely cover solar PV arrays

Solar PV panels will continue to produce power as long as they are exposed to light. Even without sunlight, they may generate power when exposed to other light sources, such as emergency scene lighting or intense flame fronts.

Although not utilized at most firefighting incidents, it is important to understand how to safely cover solar PV arrays to prevent power production and frustrate light transmission. To properly block solar panels, a salvage cover must be:

• Opaque.
• Black or dark green.
• Heavy-duty. All but the heaviest salvage covers will allow some light penetration.
• Tested and verified safe for use on solar PV systems. Many jurisdictions will mark salvage covers that have already been tested and proven to be sufficiently opaque.
• Placed over the entire system. If any part is left exposed, the system can still generate power.

Do NOT use foam blankets or untested salvage covers. Light will penetrate a foam blanket, and the coverage will deteriorate over time. Light can also penetrate lightweight to medium tarps and salvage covers. Even a heavy cover should be tested and proven opaque prior to being used in a solar PV system incident.

Be aware that covered solar PV arrays will contain stranded energy and remain a shock hazard.

Battery hazards

Batteries are hazardous because of their stored energy as well as the materials they are made from. When dealing with an off-grid or hybrid solar PV system, always note the location of the battery storage system as well as the place where conduit enters the building to reach it.

Never cut into a battery! Any conductive object that punctures a battery should be treated as if it is energized.

Batteries do not burn easily, but in a fire, they can release electrolyte, which is corrosive. Toxic fumes and flammable and explosive gases may be produced as the battery deteriorates.

Take these precautions to stay safe from hazardous battery materials:

• Handle spilled electrolyte appropriately and with caution.
• Prevent open flames and avoid creating sparks, in case of explosive gases.
• Always wear full PPE and SCBA.
• Treat battery involvement as a hazardous materials release.
• If batteries are generating vapor, electrically isolate them and move to a safe position on the corner of the structure.

Risks of structural failure

The extra weight of a solar PV system can cause unanticipated or early structural failure, particularly if it was not properly engineered. Be alert for this possibility, and consider these questions during your size-up to help assess structural integrity:

• Are you dealing with lightweight construction and engineered truss systems?
• Has the roof been compromised by additional loads, such as snow, rooftop vents and/or HVAC?
• How long has the roof or other structural members been exposed to heat and flame?

Establish a collapse zone around the perimeter that is 1.5 times the height of the structure. Crews should be positioned beyond this collapse zone or at the corners of the structure. Anyone who is inside or on the roof should have an escape route that maintains at least 3 feet of distance from all solar PV components.

Whenever possible, stay outside the collapse zone to avoid the risks of structural failure and falling panels.

Incident termination

Once a solar PV incident is under control, verify that all components have been fully electrically isolated. Work with Colorado Springs Utilities personnel to permanently secure the system and prevent it from feeding voltage into the occupancy or the power grid.

After the system is rendered safe, provide command personnel with an update on the situation and the status of the solar PV system. A full face-to-face briefing should take place before command is transferred.

A fire service crew should remain on the scene until the system is properly secured and an isolation area is established.

If a battery storage system is involved, expect a long-term event and the potential for battery re-ignition. Once thermal propagation has stopped and batteries are no longer off-gassing, the system should be turned over to the system installer or other skilled maintenance personnel.

Review

Follow these tactics when responding to any emergency involving a solar PV system:

• Notify and work with Colorado Springs Utilities throughout the response process.
• Size up the scene and locate all system components.
• Utilize full PPE, including SCBA.
• Maintain a safe distance of at least 3 feet from all solar PV equipment.
• Be alert for potential risks, including electrical shock and battery hazards.