The Continuum of Emergency Situations Involving Electricity

This section will cover information relating to the continuum of emergency situations involving electricity:

Introduction to the Continuum of Emergency Situations Involving Electricity

Situation: Substation Emergency

Situation: Emergency at a Padmount Transformer

Situation: Residential Structure Fire

Situation: Downed Power Lines

Situation: Tree on a Power Line

Situation: Fire at a Power Pole

Situation: Downed Power Lines on or Near a Car

The Emergency Response Vehicle

Introduction to the Continuum of Electrical Emergencies

There are a number of different situations in which electricity is involved. As such the continuum of potential emergency situations is also very broad. The types of electrical emergencies have been broken down into categories according to the different factors involved in the situation.

The continuum can range depending on the number of people involved (i.e. range is from one individual person to a family or a larger group of people). The continuum can also range depending on where the emergency situation is taking place (i.e., at a residential home, at a larger building or at an electrical facility). There are a number of different considerations relating to electrical emergencies that depend on where the emergency is taking place.

If an emergency involves a part of the electrical power system, there will be different concerns and considerations for emergency responders than in other types of buildings. Electrical emergencies in these areas require special considerations. When emergency responders are called to an emergency involving electricity, the local power supplier should be contacted immediately.

In different jurisdictional areas there are often safety regulations governing the safe limits of approach for power lines and equipment. In the province of Nova Scotia, the Regulations of the Occupational Health and Safety Act stipulate that no person shall carry out work that may bring a person or object closer than 6.0 metres (m) to an overhead energized power line or power line equipment where the voltage of the overhead energized power line is not known. These regulations are outlined in the Occupational safety general Regulations of the Nova Scotia Occupational Health and safety Act. You can access this legislation by single clicking on the following link: http://www.gov.ns.ca/just/regulations/regs/ohsgensf.htm

No person shall carry out work that may bring a person or object closer than the distances set out in the following table:

Phase to Phase Voltage of Energized Electrical Power Line or Power Line Equipment	Distance
750 volts and up to 69,000 volts	3.0 m
greater than 69,000 volts and up to 138,000 volts	5.0 m
greater than 138,000 volts	6.0 m

As an emergency responder, there are many situations that you might encounter involving electricity. In the following sections, we have highlighted information concerning a number of situations that you might encounter (or may have encountered in the past). Read through all of the situations to familiarize yourself with the principles of electrical safety in the application of emergency response. Many of the principles of these particular situations can be applied in other circumstances and contexts depending on the situation you are facing.

Emergency scenes are often unstable with a lot going on at once. It is important to take electricity into account in your initial survey of the scene as there may be hidden dangers that are not immediately apparent. This might include downed electrical wires as well as exposed wiring. It is important to remember that downed wires that are not in the immediate vicinity can still have an effect on your immediate response area. When electrical hazards are present you also have to start thinking about other everyday objects and substances in different ways. Highly conductive materials such as metal (watch out for those chain linked fences) as well as the presence of water can be very hazardous. Also be aware that electricity may cause associated sparking and if there are any gas or sewer line leaks, the threat of explosion will be a consideration. When dealing with emergency situations involving electricity it is absolutely necessary to think differently about many things. This includes your approach to emergency victims, the use of everyday response equipment such as aluminum rescue ladders, the use of water as an extinguishing agent and many other considerations. Read on to find out more about how to handle different electrical emergency situations.

Situation: Substation Emergency

• Once it has been determined that a component of the electrical system is involved in the emergency, the local power supplier should be contacted immediately. Normally there is an unpublished special emergency dispatch number for the power supplier that is provided to emergency dispatch services. This allows the deployment of needed electrical assistance to the scenes of accidents and emergencies.

• When you arrive on the scene of the electrical emergency, always do a quick survey of the area. Take in all the information that you can about what you will be dealing with. Remember that electricity moves through the electrical system and that problems and issues in one part of the system may be transferred to other parts of the interconnected system. Be sure to park your vehicle a safe distance from the scene. Remember that electricity seeks all paths to ground and the ground itself might be energized. Note the location of surrounding power lines: be sure not to park the vehicle underneath a power line. Power lines that are subjected to extreme heat may expand and snap.

• At a substation, do not proceed with your emergency response measures until given the go ahead by the local power supplier that the structure is electrically safe. Once this is the case, emergency responders can proceed with their life preserving duties.

• While waiting for the structure to be electrically controlled and contained, emergency responders may be engaged in related protective actions. Protective actions are those steps taken to preserve the health and safety of emergency responders and the public during an incident. In this case, isolating the hazard area while the power supplier personnel make the structure electrically safe would be a required course of action.

• Protection of adjacent structures will be an important concern while waiting for the structure to be made electrically safe. This might mean denying entry from the surrounding area as well as evacuating adjacent structures. Evacuation means moving all people from a threatened area to a safer place. To perform evacuation, there must be enough time for people to be warned, to get ready, and to leave an area.

• 'In-place protection' is a course of protective action where people inside a building are directed to remain inside until the danger passes. As an emergency responder, you may have to communicate with those in nearby buildings, to let them know that they must wait until the local power supplier personnel have secured the area electrically before it is safe for anyone to be able to safely enter or exit the structure.

• Once the scene has been made electrically secure and you are able to proceed, think about the associated emergency approach you will be using. If the use of ladders is necessary, be particularly careful of aluminum ladders or other emergency extension devices in relation to overhead power lines as well as the surrounding metal fence of the substation.

• Think about the structure you are entering: look for possible overhead hazards. Remember that a transformer tank contains large amounts of combustible oil. Other parts of the system such as capacitors and porcelain bushings may explode if subjected to heat. It cannot be emphasized enough that you MUST ensure that victims are clear of electricity before proceeding with assessment of the victims.

• Remember that there should NEVER be unauthorized persons around these aspects of the electrical system. Emergency responders should remove unauthorized persons and talk to them about the danger of the situation. Emergency responders should let the persons know of the extreme dangers. Always report any/all tampering with electrical access to the local power supplier.

Situation: Emergency at a Padmount Transformer

• Remember that there is NEVER a reason to tamper with electrical equipment. If an emergency responder sees someone tampering with a padmount transformer by trying to pry it open or jam in a stick or other object, they should intervene immediately. Stop the person from what they are doing in order to protect the person, protect the equipment and preserve electrical service. The perpetrator should be intercepted and talked to about the danger of the situation. Perhaps the person does not understand the true dangers of their actions. The local power supplier personnel can be contacted for assistance, if necessary. Damage to any component of the electrical system should be reported to the local power supplier so that they can take action to amend the situation, especially if equipment has been opened or there are exposed parts.

• Once it has been determined that a component of the electrical system is involved in the emergency, the local power supplier should be contacted immediately. Normally there is an unpublished special emergency dispatch number for the power supplier that is provided to emergency dispatch services. This allows the deployment of needed electrical assistance to the scenes of accidents and emergencies.

• When you arrive on the scene of the electrical emergency, always do a quick survey of the area. Take in all the information that you can about what you will be dealing with. Remember that electricity moves through the electrical system and that problems and issues in one part of the system may be transferred to other parts of the interconnected system. Be sure to park your vehicle a safe distance from the scene. Remember that electricity seeks all paths to ground and the ground itself might be energized. Note the location of surrounding power lines: be sure not to park the vehicle underneath a power line if the power system is involved in the emergency. Power lines that are subjected to heat may expand and snap due to extreme heat. The lines can also fall due to falling trees, high winds, extreme ice and as a result of car accidents.

• It cannot be emphasized enough that you MUST ensure that victims are clear of electricity before proceeding with assessment of the victims.

Situation: Residential Structure Fire

• It cannot be emphasized enough that you MUST ensure that victims are clear of electricity before proceeding with assessment of the victims.

• Most residences receive electrical service at 120/240 volts. Larger buildings housing businesses and industrial plants can have widely ranging voltages for electrical service. Removing a power meter is NOT a recommended way of isolating the power. Pulling the meter can be extremely dangerous, especially in the case where the structure is on fire or there is a problem with the electrical system. The more current that is flowing through something, the higher the likelihood of a large arc or explosion. High currents could be flowing through the power meter and interrupting it could cause more of a problem than you have in the first place! Additionally, an empty meter socket leaves exposed energized parts that are hazardous to anyone in the area.

  In the case of a residential fire it is often preferable to leave the power on, in the early stages, for lighting. Firefighters should avoid spraying water directly on the electrical service entrance and the electrical panels in the home - a "C" rated extinguishing agent or a 'fog' nozzle should be used for this, until it is disconnected. Once a structure fire has progressed to a point where the structure's electrical system is a hazard to firefighters, ceilings and walls have opened and the insulation has burned off the wires. At this point there will be many other hazards just as, or more dangerous.

  With residential fires, the use of ladders or other emergency extension devices may be necessary. Always be aware of extension devices and their placement in relation to overhead power lines.

  With any emergency response scene it is important to secure the scene before you leave so as to minimize the chance of accident or injury for others that come by. If the power supplier has not been involved in a residential emergency you should call them to ensure that the power lines leading to the structure are cut so that damaged and exposed wiring is not dangerous.

Situation: Downed Power Lines

• Any time that power lines are on the ground, is a very dangerous situation. As has been previously mentioned, there are many different ways that power lines can be downed. Energized lines that are down may not smoke; they may not dance around. They may not give any indication that they are still live.

• When you arrive at the scene of a power pole emergency, do a visual survey to determine how far reaching this potential emergency will be. With regards to power poles specifically, see if you can determine the danger zone for where the broken parts of the line are located. Remember to consider the ground surrounding these downed lines to be energized.

• If power lines that are down make contact with conductors on the ground such as a chain-link fence, the fence will provide a path from the line to the ground and will be energized. Metal chain link fences can extend for large distances and similarly have been known to carry electricity from downed wires for great distances as well.

• Any time you are dealing with any type of emergency at a power pole, ALWAYS act as if the wires are live. Never assume that a wire is not live. Always act as if a downed wire is live and dangerous. Sometimes, downed power lines automatically trip out when they fall down. Other times, they do not and whatever they touch becomes energized. There is no way to tell if they are live or dead, without specialized equipment - ALWAYS assume they are live.

• There are two ends of a power line - think of both, and not just the one that is in front of you. They both should be treated as "live" lines. Never touch a downed power line as it can hurt or kill you. Never think that power lines have been shut off, or that the lines are not live. Power lines do not have to arc or spark to be live. Also, the power can come back on automatically without warning.

• Many people mistakenly believe wood to be a good insulator. Although it can be in certain situations, wood can also be a great conductor of electricity. The natural presence of moisture, sap and/or the preservatives used to treat the wood can increase the conductive properties of the wood.

Situation: Tree on a Power Line

• Once it has been determined that a component of the electrical system is involved in the emergency, the local power supplier should be contacted immediately. In the situation of a tree coming down on a power line, there may be damage to insulators on nearby poles, or to the poles themselves. Power may be able to flow from the power line to the power poles. In this case, current will travel down the power pole to the ground. The pole and surrounding ground would be energized.

• A tree coming down on a power line would also cause power to flow to the tree from the power line. In this case, current will travel down the tree to the ground. The tree and surrounding ground would be energized. The tree may be on fire or smoldering.

• The best course of action is to wait for the power authority to safely remove the tree and check the adjacent poles and electrical equipment for damage. During this time, emergency responders may be engaged in related protective actions. It is important to keep bystanders safely away from the affected area until the scene has been electrically controlled and contained.

Situation: Fire At a Power Pole

• Once it has been determined that a component of the electrical system is involved in the emergency, the local power supplier should be contacted immediately. Normally there is a special emergency dispatch number that is provided to the Emergency dispatch services so that they can dispatch needed assistance to the scenes of accidents and emergencies.

• In the situation of a fire at a power pole, power may be able to flow to the pole from the upper hardware components. In this case, current will travel down the pole to the ground. This is often what causes the fire.

• A fire caused by the flow of current to a power pole will not be able to be extinguished until the power supply is turned off.

• When you arrive on the scene of the electrical emergency, always do a quick survey of the area. Take in all the information that you can about what you will be dealing with. Power lines that are subjected to heat may expand and snap due to extreme heat.

• The best course of action is to wait for the power authority to cut power to the pole, before trying to put out the fire. While waiting for the structure to be electrically controlled and contained, emergency responders may be engaged in related protective actions. In this case, isolating the hazard area and protecting adjacent structures are important areas of concern while waiting for the structure to be made electrically safe.

Situation: Downed Power Lines on or Near a Car

• If a power line breaks and falls near a car, electricity can get to ground through the car's tires. The tires on the car are not good insulators since many tires are wrapped in steel belts, which can conduct electricity. As well, rubber in the tires contains carbon and can conduct electricity. Electricity can cause the air inside the tires to heat up and the air expansion can cause tires to explode.
  

• If the wire is down on another vehicle it us up to you to let the occupants know what to do.

• When a live power line touches a car, both the car and the ground around it are dangerous. The following tables outline the different combinations of factors that must be considered in this situation.

Condition	Present	Action
If the car is still operational in the vicinity of a fallen power line		Instruct the person to slowly and carefully back the car away from the power pole.
If it is certain that the vehicle is not hooked to a wire and no part of the pole or associated equipment is resting on the vehicle
If one of the vehicle occupants is physically able

Changes in any of these three factors will necessitate different actions.

Condition		Action
If the car is no longer operational and there are no other impending dangers for the victims		Instruct the occupants that they MUST stay in the car until help arrives. They must not touch the car and ground at the same time! Do not go near or touch the car! Do not attempt to move any fallen wires yourself. Wait for the personnel of the local power supplier to make the situation electrically safe. It is the job of the emergency responder to undertake crowd control procedures to ensure that no other persons get in the vicinity of this emergency and to ensure that no other bystanders come into contact with energized objects.
If the vehicle is hooked to a wire and there are no other impending dangers for the victims		Instruct the occupants that they MUST stay in the car until help arrives. Do not attempt to move any fallen wires yourself. Wait for the local power supplier personnel to make the situation electrically safe. It is the job of the emergency responder to undertake crowd control procedures to ensure that no other persons get in the vicinity of this emergency and to ensure that no other bystanders come into contact with energized objects.
If there are impending dangers and it is impossible to wait for the situation to be made electrically safe (i.e., fire or explosion)		If a downed power line is on a vehicle, the passengers of the car are safest if they stay in the car. But if there are other dangers and they must leave the car, the first thing to do is to have the person on the inside open the door wide and give themselves lots of room. Instruct them not to touch the ground! Next, instruct the person to jump with both feet together with their hands well away from the car. The purpose of this procedure is to avoid touching both the energized vehicle and the ground at the same time. Make sure that the person does not touch the car as they jump and that they do not reach to touch the car to regain their balance. Once the person lands, they must hop with both feet together or shuffle with their feet together until they are at least 7-8 metres away from the car. Do not go near the car or allow anyone else to go near the car for any reason. If the car is on fire and the occupants cannot escape safely, firefighters can fight the fire using the proper knowledge and equipment. Foam that is rated for class "C" fires. Water may also be applied using a "fog" nozzle. The fog nozzle sends out droplets of water, rather than a straight stream that could conduct electricity back to the firefighter. Click here to see the previously presented information on the fog nozzle.

When the Emergency Response Situation Involves a Flood

As was mentioned previously, when electrical hazards are present you also have to start thinking about other everyday objects and substances in different ways. Water is an excellent conductor of electricity. Regardless of the location of the flood, take action to have power shut off to any equipment or appliances in the affected areas. In a residential basement this might mean a furnace, a motor or other electrical appliances. The best course of action is to shut off the electricity for the entire structure. If the area and the fuse box or circuit breaker are wet, stand on a dry board and shut off the main power using a dry wooden stick. materials such as water can pose additional hazards in the presence of electricity. Remember: Pulling the power meter is not a recommended way of isolating the power!

The Emergency Response Vehicle

The emergency response vehicle is what gets you to an emergency. However, where electricity is concerned there are important electrical safety considerations. It is a well-publicized myth that the tires of a vehicle are insulators. This is not the case as electricity can cause extreme internal and external damage to the rubber. Thus tires of a vehicle that have been exposed to electricity may look fine, but in fact they might fail in a few minutes, after several hours or after several days. For your safety, it is always advisable to allow tires to cool for several hours before examining them. Have tires inspected by a qualified tire facility.

This section has examined how to deal with a number of different emergency situations involving electricity. This knowledge will be important to you in making informed decisions with regards to emergency situations involving electricity.

A Foundation of Electrical Knowledge The Electrical System Fire and Electricity The Continuum of Emergency Situations       Involving Electricity

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