Incidents involving electricity PN796

Question 1

Rescues - When carrying out a rescue in the vicinity of overhead lines, substations and other electrical equipment belonging to the electricity supply industry what is the minimum safe approach distance

Answer 1

5m

Question 2

minimum safe distance on overhead cables - using ladders/aerial appliances

Answer 2

10m (20m in training)

Question 3

minimum safe distance - In dense smoke or flames approaching conductor

Answer 3

10m

Question 4

minimum safe distance when using hand held jets on overhead cables

Answer 4

20m

Question 5

minimum safe distance when using ground monitor on overhead cables

Answer 5

30m

Question 6

At premises where a sub station has been provided within a building the transformer chamber/sub station will be situated against an outer wall. The wall and floors separating it from the remainder of the building will have at lease how many hours standard of fire resistance?

Answer 6

4hrs

Question 7

What will supply or distribution facility display?

Answer 7

a unique identifier on a conspicuous indicator plate

Question 8

Can crews lift covers to further expose a pavement level cable system to extinguish fire

Answer 8

No - unless the authorized person has confirmed that power has been isolated and residual current has been discharged

Question 9

Once current is switched of to high or low voltage installations is it render safe

Answer 9

No - residual charge of electricity may be present in apparatus - residual charge needs to be made safe by authorized person

Question 10

Electrical hazards in a fire situation

Answer 10

Large quantities of fuelmay be stored (within power stations)
Oil filled transformers
Insulating materials
Gearbox oil

Question 11

Insulating materials at incidents involving electricty?

Answer 11

PVC - toxic smoke
PCB (Polychlorinated Biphenyls) - insulating liquid (not always labelled)
SF6 (Sulphur Hexafluride) - insulating gas

Question 12

On arrival to incidents involving electricity actions (general)?

Answer 12

locate responsible person

Question 13

On arrival at overhead cables?

Answer 13

request urgent attendance of National Grid

Question 14

On arrival at a Substation?

Answer 14

request urgent attendance of authorized person

Question 15

On arrival of Fire and Explosions in pavement level ducting

Answer 15

immediate attendance of authorized person. cordon & do not touch

Question 16

On arrival of Wind Turbines?

Answer 16

request isolation of any power supplies to the wind turbine and confirm that the blades have been “locked out”

Question 17

Ops procedure for pavement level cable systems fires?

Answer 17

Under no circumstances should crews seek to lift covers or further expose a pavement level cable system to extinguish the fire unless the authorized person has confirmed power isolated and residual current discharged

Question 18

What will National Grid pylons and energy operators premises have?

Answer 18

unique markings/ identification plates this information must be included in any message

Question 19

If there is the possibility of high voltage present can f/f enter the risk area?

Answer 19

No - if any possibility at all no entry to risk area is to be made

Question 20

If it is confirmed the residual electrical supply is of low voltage can action be taken?

Answer 20

Yes providing appropriate controls are put in place e.g electrical gloves

Question 21

Ground and aerial appliances should not be used within how many meters from a live conductor?

Answer 21

30m

Question 22

what is the distance (corridor) for firefighters and equipment when dealing with overhead power lines

Answer 22

10m either side of the overhead cable (measured along the ground)

Question 23

what is the usual cordon recommended as a starting point for wind turbine fires?

Answer 23

300m

Question 24

Can rescue be made from electrical apparatus?

Answer 24

supply must be shut down! if the voltage is known to be 3300v or less LFB electrical gloves will provide adequate protection

Question 25

when can electrical gloves be used?

Answer 25

when voltage is known to be less than 3300v

Question 26

A person is seen to be lying on top of a transformer, switch, or anywhere else above ground level can we attempt a rescue?

Answer 26

No - they must not be touched until word is received from an authorized person of electricity authority that it is safe for rescue work to be carried out

Question 27

What is high voltage?

Answer 27

greater than 1000volts ac (or 1500volts DC)

Question 28

What is low voltage?

Answer 28

less than 1000volts ac (or 1500 volts DC)

Question 29

What is UPS?

Answer 29

UPS is a Uninterruptible Power Supply (e.g battery banks)