Incidents involving electricity

Question 1

Electricity company premises include?

Answer 1

• Power stations powered by a range of methods
  including fossil fuels such as coal, oil , gas and wood
  chip.
• Sub stations indoor or outdoor.
• Fenced enclosures containing transformers.
• Distribution cables/equipment, including cables
  mounted on poles, towers and pylons. Pavement
  level electrical ducting.

Question 2

Sub stations that are situated within a building will offer how many hours fire resistance?

Answer 2

At least a 4 hour standard of fire resistance.

Question 3

Sub stations within a building will be situated where?

Answer 3

Against an outer wall with the floors and walls separating it from the remainder of the building.

Question 4

If smoke is issuing from pavement inspection covers what should you not do?

Answer 4

Remove the inspection cover as explosions have injured crews in the past.

Question 5

When high voltage equipment comes into contact with heat or smoke what may occur?

Answer 5

Arcing can occur as this increases the conductivity of air to earth or adjacent structures.

Question 6

Does switching off current to a high or low voltage installation render it safe?

Answer 6

No as a residual charge of electricity may be present in the apparatus.

Question 7

As well as large quantities of fuel what other hazardous substances may be found at power generating stations?

Answer 7

• Methanol
• Propane
• Hydrogen
• Methane
• Chlorine
• Oxygen

Question 8

Some transformers and switch gear are protected by fixed installations which when operated fill there compartments with what?

Answer 8

Carbon dioxide or vaporising liquid.

Question 9

What should crews NOT do until an authorised person arrives?

Answer 9

Pass warning signs or gain access to areas which have warning signs.

Question 10

What extinguishing media could you use which doesn’t damage electrical equipment?

Answer 10

Carbon dioxide or vaporising liquids.

Question 11

If it is necessary to use ladders or aerial appliances in close proximity to overhead cables who should you take guidance from? and what is the minimum distance you should be from them?

Answer 11

The Authorised person and any equipment should be 10 metres from them.

Question 12

Ground and Aerial monitors should not be used within what distance?

Answer 12

30m of the live conductor.

Question 13

Water or foam should not be used directly onto live apparatus unless?

Answer 13

It is confirmed that only low voltage electrical supplies are involved and no other extinguishing media is available.

Question 14

How far should firefighters position themselves from overhead power lines?

Answer 14

10m in smoke or flames approaching conductor.

Question 15

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 15

5m

Question 16

When using hand held jets what is the minimum safe approach distance?

Answer 16

20m

Question 17

LFB electrical gloves can be used at what voltage or less?

Answer 17

3300v

Question 18

If a person is seen lying on top of a transformer, switch or anywhere else above ground level could you try a snatch rescue?

Answer 18

No they must NOT be touched until word is received from an authorised person from the electrical authority that it is safe to do so.

Question 19

Equipment described as high voltage is above what voltage?

Answer 19

Greater than 1000 volts ac or 1500 volts DC anything under this is low voltage.

Question 20

What does UPS stand for?

Answer 20

Uninterruptable power supply.

Question 21

What is a battery bank?

Answer 21

A Battery bank is a means of providing auxiliary power in the event of a failure to the mains supply. This provides the uninterruptable power supply.