Electricity Flashcards

1
Q

Electrical gloves rating

A

If the voltage is known to be less than 3300V, electrical gloves may be used to isolate
damaged apparatus.

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2
Q

At premises where a sub-station has been provided within a building, the transformer
chamber/sub-station will be

A

situated against an outer wall. The walls and floors separating it from
the remainder of the building will have at least a four hour standard of fire resistance.

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3
Q

Switching off the current to a high or low voltage installation, such as a cable, transformer or
switch-gear does not necessarily render it safe, as a

A

residual charge of electricity may be

present in the apparatus.

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4
Q

The commander of the first appliance in attendance is to locate the ‘responsible person’ where
available, and gather all relevant information to formulate a firefighting/rescue plan.

(d) Fire and explosions in pavement level ducting. Request the immediate attendance of
the authorised person.

A

(a) At power stations liaise with site personnel and comply with site specific or operational
contingency plans.
(b) Overhead cables and pylons contact National Grid and request urgent attendance of
authorised person.
(c) At a substation or part of the distribution network (for example London Power Networks
PLC/EDF Energy/Scottish Power) request urgent attendance of authorised person.

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5
Q

The attendance time for the authorised person may take up

A

to 2 hours

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6
Q

In some instances, after all reasonable efforts have been made the authorised person may not be
able to confirm all electrical supplies are isolated, without entering the compartment and testing
the apparatus. In this situation the IC must assess the risk against the benefits of any possible
action.

A

(a) If there is any possibility that high voltage supplies may be present no entry into the risk area
should be made.
(b) If it is confirmed the residual electrical supply is of low voltage then action can be taken,
provided appropriate controls are put in place.

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7
Q

Rescue

A

Rescue
Prior to attempting rescue or retrieval of persons from contact with electrical apparatus, the
supply must be shut down.
If the voltage is known to be 3300V or less, LFB electrical gloves will
provide adequate protection.
Should a person be seen lying on top of a transformer, switch, or, anywhere else above ground
level, they must NOT be touched until word is received from an ‘authorised person’ of
the Electricity Authority that it is safe for rescue work to be carried out.
High voltage apparatus is seldom located less than 2.5 m above ground. Protective screens are
used where such apparatus cannot be placed 2.5 m above ground. In both cases the advice from
the authorised person should be sought prior to carrying out rescue/retrieval of persons.
6.31 Any rescue from a tower or pole should be made by personnel with the necessary specialist skills
and equipment, once it is confirmed that the supply has been isolated by the authorised person.

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8
Q

SF6 what is it and describe

A

Sulphur Hexafluoride (SF6): This gas is used as an insulating and interrupting medium in many
types of electrical apparatus .It is heavier than air and will not disperse easily and can act as an
asphyxiate in confined or low lying areas. BA and full fire kit should be worn when encountering
SF6, and in the event of it being involved in a fire or other reaction, the advice of a hazardous
materials and environmental protection officer (HMEPO) or scientific adviser should be sought
since hazardous breakdown products may be present in the form of a gas or powder. This
powder may contaminate the immediate area.

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9
Q

what are PCBs and describe

A

Polychlorinated Biphenyls (PCBs): PCBs, which are used in some transformers and other
electrical equipment as an insulating liquid, are highly toxic and have harmful environmental
effects if released, as they are not biodegradable. Some, but not all, transformers are labelled to
indicate if they contain PCB

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10
Q

PVC insulation:

A

PVC insulation: When involved in fire will produce large volumes of toxic and irritant smoke
which will contain hydrogen-chloride gas

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