Electrical Power

Incident with individual in vehicle with downed wires

- Stay 30 feet away from vehicle til power locked out Accepted ruled for safe distance it to keep people back at least 1 1/2 distance between the poles -When possible have individual stay in care even if injured. -If must leave due to injuries or fire- have victim jump clear away from vehicle without touching vehicle and ground at same time. - Have them jump as far as possible and land with both feet at same time. Tell them to shuffle away keep feet close together to prevent step potential.

Downed Wires Fire Dept

-Do not leave scene of wires down where sparking EXTREMELY DANGEROUS AND VIGILANCE REQUIRED to restrict people from area. Never apply water to area near the arching wires and personnel should remain congnizant of step potential. -DO NOT Move wires or use tools or rope to move wires.

Interstital space considerations

-Firefighters should be aware of these unique spaces and may be required to check these spaces with atmospheric monitoring equipment. Emergencies in this space may require building engineer or utility company assistance. -SCBA shall be worn when investigating emergencies within these spaces.

Interior Vaults

-Fires interior vaults are highly dangerous and potential for tremendous damage -DO not enter any vault until utility company confirms power off. *** Important to note that interior vault fires located in structures is the off-gassing of CO found in vault. Buildup could cause an explosion- potential for injury and death. During size up- be cognizant of build up of gases and monitor the air quality as progress. MAINTAIN a strong situational awareness due to the potential of smoke and lack of visibility. To be proactive can vent the building while awaiting power company as long as will not draw fire into the uninvolved area. Venting reduces probabilities of CO explosion.

Interstitial Spaces

-Intermediate space located between regular -use floors -commonly located in hospitals and lab type settings to allow space for mechanical systems in the building. By providing this it allows hospital rooms and labs to be rearranged throughout their lifecylces and therefore reduce lifecycle cost.

Non PCB labeled Transformers

Contain up to 10% PCB contents All shall use Breathing apparatus on Transformer Fires

Underground electric vaults, manholes or substations

Firefighters should never be allowed to enter! Transformers and other electrical equipment can cause dangerous explosions. -REQUEST assistance of electrical company immediately and focus their efforts on securing the area around hazard to prevent civilian injuries. POWER Company best handles these due to their area of expertise.

Toxic gases may be formed from electric fires in vaults:

Firefighters should take necessary precautions. -While waiting for power company to lock out power-find out what buildings receive power from the vault. -Find out if electrical conduits going to nearby buildings -When electrical wire burns in confined space gives off large amounts of carbon monoxide gas. -Firefighters should check nearby exposures with CO detection/monitoring equipment as gas can travel underground conduits and seep into nearby buildings. - Can be significant amounts to cause explosion in distant structure. -Check and continue to check CO levels while wait for utility. -If necessary evacuate the building , occupants and ventilate the building. SCBA shall be worn when investigating these types. -Firefighters shall stay clear of manhole covers over underground electric vaults; these have been know to blow off and fly 150 ft.

Request respective utility company to verify wires down

If wire arching advise their dispatch center of the situation. Utility company when not taxed due to severe weather issues upgrade response priority to arching wires. Upon notification the utility company dispatcher, the assigned drive provides an estimated time of arrival to scene, a piece of info the fires dept dispatch center can request and provide to crew. To assist the utility company pinpoint the exact area personnel should provide a pole number to the dispatch.

Voltage difference near power lines

If you are near downed power lines - as you walk away you reduce the voltage levels. The distance from one leg to the other as you walk away may bridge the current from a lower to higher voltage level and could flow through your body with devastating results. Keeping both feet together is fairly safe- if the voltage is the same there is no reason to travel. If you step away you r create a difference in voltage pressure. W When feasible stand still until qualified personnel lock out the electrical power. If you must move away shuffle your feet moving no more than a few inches at a time. Or use very short hops to move away

Electricity will travel through any material depending on resistance.

If you become a part of electricity's path to ground it will flow through your body. Resistance is measured in ohm and is the material to resit the flow of electrical current

Power poles

Owned either by power or telephone company. You may find both cable line and phone lines Power is reduced from the primary line to voltage for houses or businesses.

Apparatus Positioning for Electric wires

Positioned to avoid electric wire so lines do not fall on apparatus, firefighters, or hose lines The vehicles tires no longer provide insulation from electric shock due to impurities. High voltage may flash over the tire impurities or metal banding and conduct electricity- dirt also lowers resistance.

Electricity flows normally until a fault occurs (ground to phase to phase)

Short may occur when contact with ground is made - fuse should blow but may be circumstances when a fuse does not blow. This is the reason all lines are considered energized.

Remember Electrical Incident

THINK BEFORE YOU ACT Don't become a victim while coming to the aid of someone that has come in contact with Electric current.

IMPORTANT TO remember in an electrical incident

THINK BEFORE YOU ACT. Don't become a victim while coming to the aid of someone in contact with electrical current. STAY FOCUSED and Asses the risks.

Power from substation

Transmission lines may have up to 750,000 volts Power is split up by bus fuses and reduced to the distribution system that typically carries less than 20,000 volts to 10,00 volts. Power is distributed in multiple directions. Substations have circuit breakers and switches that can isolate power as needed. The power leaves the substation on primary lines they are not insulated and one circuit consists of 3 wires, which is considered one phase. The power is reduced again from transformed on top of poles or in ground transformed. Transformers regulate the voltage in the lines to prevent over voltage and under voltage.

Amount of current flowing

dependent on available voltage and resistance of the conductive path.

Amount of current

determines severity of electrical shock

Mercantile and Multi-residential Structure Fire

-May have numerous large switching devices - only qualified personnel should operate these. Incidents involving electric emergencies inside a structure cannot be controlled from inside and may be controlled from the outside at the main disconnect. -Electric meter is only a measuring device not a switch - may short out at the base and cause burns, eye damage, or explodes. Only a certified representative from the power company should do this procedure.

Structure Fire

-Normally electric panel safest place to lock our power. -Most panels have main switch at top of panel and individual areas may be secured by circuit breakers. -Age of home- panel may be updated with individual breaker for each circuit. Older- may have screw in fuses in which the switch next to fuse control the power only to the fuse. The switch while it looks like a breaker it is not and only isolates power once it is manually operated. The screw fuse is rated to carry a specific load if exceeded a metal bar will melt inside the fuse and stop current Fire dept should isolate the power to the corresponding fuse by switching to off before screwing out the fuse.

Downed Wires

-Secure a safe permits around entire hazard area (may include metal fencing, pooling water, rail track, guard rail-that may be in contact with downed wires) -Bystanders kept clear -Don't assume wires not energized (cable, telephone)

Two basic properties of electricity

-Voltage -Current

Pole Fires

-Water should not be used to control pole top fires unless de-energized by power company. Dry Chemical and CO2 extinguishers may be used to extinguish some fire Exposure protection is paramount. Allow pole fire to burn until power company can remove the current. NEVER ALLOW fire dept personnel to climb poles. Firefighters should avoid walking under transformers as they may contact PCBs or burning oil. Burning transformers can and do explode PPE must be worn Overhead power lines may not be coated. When coated do not consider this an insulator. DO NOT attempt to touch any power line.

Ground Transformer Fire Important

-When advised by power company that power is down- ASK how they determined it. Recently, engine company came to a scene of fire in ground transformer, made safety zone. Power company said they turned off the power and could put out fire. When the engine company questioned he advised that the power was off because traffic lights down the blow were out and circuit blown. The engine company advised power had been out for several hours. Worker went to confirm and found out it was still energized. COMPLACENCY AND IGNORANCE CAN KILL YOU!!

Symptoms of electrical contact emergency if survive

-can appear months or even years later, including loss of limb, blindness, arthritis, kidney or liver problems, and partial loss of brain or other organ functions.

Interstitial space useful

-when mechanical system of the building is highly sophisticated and changing the space on the primary floors is a distinct possibility. Sizes of these spaces range in height to allow easy access and repair or alteration. -Changes or maintenance need to be performed in the interstitial space, primary space is still functional. -Needs few vertical penetrations and therefore more open space on primary floor -Entire floor plan can be more open because there are fewer fixed vertical penetrations through the floor and wall.

House current

120/240 volts (single phase)

Commercial Current and some large houses

240/120 Delta, 208/120 Y 3 phase or 480/277 three-phase

Ground Transformers

Approach with caution. -Doors and/or shutters should never be opened before power turned off and confirmation from utility company at scene. -EXPLOSION CAN OCCUR due to accumulation of flammable gases. -After power remove extinguish remaining fire with dry chemical or CO2 extinguishers

Absolute line of approach to power lines.

Area of approach should not be encroached upon. Chart minimum and distance more is better. In wet conditions these minimums shall be expanded: Line Voltage up to 50,000 absolute limit of approach 10 ft Line voltage 50,000-115,000 absolute limit of approach is 12 feet Line voltage 115,000 to 230,000 absolute limit of approach 16ft. Line voltage 230,000 to 500,000 absolute limit of approach is 25 feet.

Electrical Fire

Best handled by shutting down the power source DO NOT use water or spray energized electrical equipment. Hose limes may be used to extinguish combustibles surrounding the equipment. Do not spray solid or straight streams on overhead power lines and substations. Remember electricity travels faster than the water leaving the nozzle. Electric current will travel back to the nozzle and operator.

Effects on the body:

Body conducts electricity due to moisture. Electrical contact is based ion shock intensity, path and length of contact Electrical injuries check for entry and exit wounds Even if electrical burn seems small on exterior- internal damage will cause infections and body's internal organs may be damage. -Electrical burns are SERIOUS burns and these victims need to be treated at the burn center. -Any victim in contact with wires must be considered energized and firefighters must use caution around them to make every effort not to touch them. -Firefighters DO NOT have equipment to prevent them from electric hazard.

as little as 50 millilamps

CAN BE FATAL- (50/1000 of amp) - amount to light 7.5 watt Christmas tree bulb.

Transformer

Carries power for up to 10 hourse.

Power plant generators 3 phase alternative current

Lines carry AC power to the transmission substation and may have 750,000 volts. As power travels along the line it loses voltage due to the distance it has to travel. From power plant the power is delivered to power substation. Similar to fire ground hydraulics the longer the line the fewer volts at the end.

Current

Measure in amps and is the amount of electricity flowing through a wire. or conductor. Electricity travels at the speed of light or 186,000 miles per second. -continuous movement of free electrons through the conductors of a circuit. -amount of current determines the severity of the electrical shock.

Utility pole numbers

NOVA normally has 2 lines Top line is map grip for which the pole is located and can span a large distance Second line is specific pole number within that grid. Personnel should make every effort to provide both numbers upon reporting pole numbers to assis the utility company determine the location quickly

Resistance

The degree of friction or opposition to motion that electrons move through conductors.

Before raising or extending a ladder

The overhead must be checked for powerlines. With enough voltage ladder doesn't need to contact wire to become energized.

Navigating in poor visibility

When appropriate keep arms up and palms in - allowing muscles to contact inward and away if they come in contact with electric wires. If the palm of a person's hand contact current, the fingers will bend inward clenching into a fist. This causes the fist to clench the wire firmly. A person will not be able to let go until power is removed.

Wires Down

Wires will often appear to be de-energized however, you must always approach the wires as though they are fully energized until a power company representative confirms otherwise.

Electricity current travel

all available conductive paths, not just the least resistance.

Conductor

allows the flow of electricity-low resistance that completes the path or circuit. Low resistance materials are good conductors- gold, copper, aluminum, steel, water, and human tissue. High resistance materials are poor conductors- glass, porcelain, pure rubber and plastic- Commonly known as insulators.

Electric power starts

at power plant from generators

Voltage

force motivating electrons to flow in a circuit. The pressure or force driving a current through wire or other conductor. Specific measure of potential energy that is always relative between two points. When we discuss a certain amount of voltage in a circuit it is the measurement of potential energy that exists to move electrons from on point in that circuit to another.

Step potential in electricity

has the potential for making you part of the circuit. Electricity is always trying to find the path of least resistance to complete the circuit. The ground or earth may be the path the electricity attempts to take. When it reaches the ground it spreads out like a ripple in a pond. The point of contact the electrical pressure is at full force as is spread out in all directions that can be an extremely hazardous condition.

Power that runs these generators at powerplant can come from

hydroelectric dam, diesel engine, gas turbine, or in most cases a steam turbine.

Safest insulator for electricity

is DISTANCE This distance is depended on the voltage and humidity.

Computerized system manages electrical grid

it will detect defaults and try to resume power. This action will cause a harmless wire to surge 20,000 volts without being aware.

Average electrical contact emergency

occurs every day in the home or workplace in the US.

Amount of current in a circuit depends

on the amount of voltage available to motivate the electrons and also the resistance in the circuit to oppose electron flow and the amount of resistance in the circuit to oppose electron flow. Just like voltage, resistance is quantity relative between 2 points. Due to this the quantities of voltage and resistance are often stated as being between or across two points in a circuit.

Most hazardous conditions involving power lines

ones that do not come in contact with the ground.

Secondary lines

power lines from pole to a house or business Normally consist of 3 lines 2 insulated- carry power 1 uninsulated - nuetral (some cases may be insulated)

UG conductors

power lines under ground in newer areas. May be buried in the ground or enclosed in conduit. Primary lines are supposed to be buried 30" to 36" below grade Secondary lines are to be 24" below grade DO NOT TRUST these minimum depth requirements may be shallowed dur to final grading of property. Although not always correct- Ms. Utility should be called to mark any excavation site.

Steam turbine

powered by coal, oil, natural gas or nuclear reactor.

Voltage difference between two points is called

step potential, step voltage or ground gradient. This difference cold create and electrical path through your body.