E and B

Electrical ‘earthing’ is required for: except,

• To minimize electrical interference

• To incline electrostatic discharge between non conductive material

• To avoid over voltage due to lightning surges

• as operate electrical protective devices

Bonding is where voltage differences between electrical conducting parts are .........

(one word)

Electricity supply regulations (ESRs) require distribution transformers’ secondary neutral (of a single-phase system) or the star-point neutral (of a three-phase system) to be bonded to a ‘substantial’ earth mat. The way this is done will be defined in the specification of the local ES authority applicable. Conventionally the neutral and the earth mat are ................. at a substantial un-insulated busbar in a main switch-room and is referred to as the star-point-neutral/earth busbar (SPN-E).

(two words)

Static electrical charge is caused by the forced separation of molecules of ............ materials

(one/two words)

Techniques to control static involve the use of chemical additives to raise ..... of liquid

• conductivity

• transfer

• conductor

• resistance

Internal Parasitic Capacitance Effect, except

• noise for instrument input

• use screen of the cable to transfer signal

• earthing cable screen on transformer

• screen shall be earthed on one point for zero reference

‘dirty earth’ is applied to the return path conductor that can carry the prospective ........... from electrical equipment

(two words)

clean earth can only apply to return-path conductors, which cannot carry ................ from electrical equipment.

(two words)

It is usual to separate power-carrying cables from instrument or signal cables to reduce the risk of noise

induction.

• Crimping

• Separation

• Segregation

• Isolation

Where the cable runs through a junction box, separate ...... terminals should be provided for cores and the screen.

(one word)