5028 - Electical Hazards Flashcards
1
Q
Who does This document apply to?
A
All uniformed personnel. (It does not apply to members of the TFD Electrical Division in their performance of routine electrical maintenance.)
2
Q
For most electrical hazard incidents, TFD personnel should do what?
A
initially direct efforts at protecting people and property in the surrounding area, maintaining a safe distance from the hazard until representatives from Tacoma Public Utilities arrive.
3
Q
Who shall maintain this document?
A
The TFD Safety Officer
4
Q
Who shall:
- Identify potential electrical hazards as part of scene size-up
- Ensure that precautions are taken to prevent electrical injuries to personnel
- Ensure the public is kept away from areas of electrical hazard at emergency scenes
- Request the appropriate power utility to respond whenever emergency operations must be performed near electrical lines or distribution equipment
- Await authorization from TPU representatives before allowing TFD personnel to enter a electrical substation or vault
- Follow TFD policies and procedures pertaining to confined spaces when supervising operations involving electrical vaults
A
Incident Commanders
5
Q
Who shall:
- Wear full protective clothing at emergency scenes involving electrical hazards
- Be aware of the limitations of turnout gear as protection from electrical hazards. (Refer to 6.1) 3. Remain alert for electrical hazards when conducting operations on the interior or exterior of a structure
- Determine the location of overhead and underground electrical conductors when working on or near the exterior of a structure
- Be observant for potential electrical hazards any time when raising, using, or lowering ground ladders
- When participating in roof operations, be cognizant of the location of wires above, below, and at the roofline
- When hoisting or lowering, patients, personnel, equipment, tools, or fire hose, or when removing debris from roofs or upper floors, take care to avoid electrical wires
- When switching off breakers at an electrical panel, do so in accordance with 6.2
- When dismounting an apparatus that is in contact or about to be in contact with an energized conductor, do so in accordance with 6.7
- Know that electrical vaults are confined spaces
A
All Personnel
6
Q
Personnel shall NOT:
A
- Cut electrical wires, open transformers, or pull power meters
- Operate switches or controls on electrical poles, or in manholes, underground electrical vaults, transformers, or substations
- Enter flooded basements or rooms in order to access electrical service panels
7
Q
Only who , shall cut electrical wire drip loops, open transformers, or pull power meters?
A
personnel from Tacoma Public Utilities, or other power companies
8
Q
At all times, aerial equipment shall be kept:
A
- At least ten feet from energized electrical lines rated up to 50 kv 2. At least ten feet—plus 0.4 inches for each 1 kv—from energized electrical lines rated above 50 kv
9
Q
For low voltage lines (750 volts or less), aerial equipment shall be keep _______________.
A
far enough away from the lines to prevent firefighters from contacting the energized conductor.
10
Q
Personal protection from electrical hazards
A
- Don full protective clothing—including eye protection—for emergency incidents involving electrical hazards.
- Understand that full protective clothing provides little protection from electrical shock.
a. The rubber in boots offers only limited resistance to current.
b. Leather gloves are ineffective as insulators; they are not substitutes for lineman’s gloves. - Know, however, that full protective clothing does provide protection from other injuries at electrical emergencies, such as flash burns and trauma from flying objects.
- When working in areas of decreased visibility, keep at least one hand out in front of you, the palm toward your body.
a. If the back of your hand receives a shock, the resulting muscular contractions should pull your hand away from the electrical source.
b. Otherwise, with palm outward, the shock may cause you to tightly grip the source, resulting in serious injury.
11
Q
Disconnecting electrical service to a structure:
A
- Do not attempt to cut any wires, including the drip loop.
- Do not attempt to pull the electrical meter.
- Do not enter a flooded basement to shut off the power.
- Disconnect the power at the service panel only if the firefighter, the panel, and the floor are dry.
- Realize that many structures have back-up generators or other emergency power sources that will automatically engage and re-energize some or all circuits whenever the main power source is interrupted.
- Have Tacoma Public Utility personnel disconnect the electrical service if TFD personnel cannot safely shut off the power at the service panel.
12
Q
Responding to Downed Wires or Damaged Utility Pole
A
- Establish the Danger Zone.
a. Use the “one-span” rule—
b. Consider increasing the size of the Danger Zone if the ground is wet,
c. Enlarge the Danger Zone accordingly if a wire is in contact with a guardrail or metal fence.
d. Use an adequate number of firefighters, law enforcement, or personnel from the power utility to prevent entry into the Danger Zone.
e. Consider using fire tape or rope to mark boundaries. - Assume that all electrical wires are energized.
- Do not assume that telephone, cable TV, or guy wires are harmless.
- Realize the ground itself may become energized by a fallen wire.
- If rescue or patient extrication is necessary, wait for Tacoma Public Utilities to shut off the power before anyone enters the Danger Zone.
13
Q
Utility Pole or Tower Fires
- Brush or Grass Fires near the base .
- Fires near the top of poles a.
A
- a. Extinguish with conventional means.
b. Notify TPU, as even large metal towers can be structurally weakened if exposed to fire - a. Position the apparatus clear of the wires.
b. Keep all persons away from the pole and all wires the pole supports.
c. If it appears that no further damage will result, leave the fire alone and await TPU.
d. Otherwise, if the fire appears to be weakening the pole, support arms, or electrical wires, consider directing a fog stream over the top of the pole, allowing water droplets to rain down on the fire.
14
Q
Choosing extinguishing agents for electrical fires or fires near electrical hazards
A
- Avoid using water streams.
a. Water streams pose safety hazards when used near energized electrical wires or equipment.
b. Water streams can also damage electrical equipment or cause arcing between wires.
c. Because conductivity depends on many variables—the size of the stream, the type of nozzle, the purity of water, the voltage involved—it is impossible to determine safe distances for all possible situations.
d. It is recommended that before using water, TFD personnel wait for the electrical equipment to be de-energized and for authorization from TPU.
e. For fires in electrical substations or vaults, it is required that TFD wait for the electrical equipment to be de-energized and for authorization from TPU. - If water is necessary, maintain a minimum distance of ten feet and use fog streams, not solid streams.
- Consider using portable fire extinguishers with a Class C rating as an alternative to water.
a. Class C extinguishing agents are not conductive.
b. The metal cylinder, however, is conductive and the discharge horn may become conductive when wet or dirty. - If a vault can be sealed adequately and there is sufficient extinguishing agent available, consider carbon dioxide flooding.
15
Q
Emergencies in electrical substations and vaults:
A
- Protect people and property in the surrounding area.
- Maintain traffic control and await the arrival of power company personnel.
- Do not enter or attempt to fight a fire until representatives from the power company arrive to give authorization and provide technical assistance.
- Do not operate electrical switches or controls.
a. Many switches are not designed to be operated when current is flowing.
b. Improper operation can result in dangerous arcing, damage to equipment, or cause the switch to explode. - Be aware of the safety risks to firefighters:
a. Fire and explosion hazards from transformer oil
b. Equipment that cannot be de-energized
c. Energized soil and/or pools of water
d. Arcing and exploding insulators
e. Toxic gases from burning insulation and oil
f. Explosions when manhole covers are disturbed or removed - Realize that all TFD policies and procedures regarding confined spaces apply to underground electrical vaults.
