What is the symbol for 'current carrying capacity' of your selected cable ?

Ib

In

Iz

It

What is the symbol for 'PROTECTIVE DEVICE RATING' in AMPS ?

Ib

In

Iz

It

What is the symbol for current after the application of 'factors' ?

Ib

In

Iz

It

Which one of the following is not a recognised 'factor' used when sizing conductors ?

Ci

Ca

Cg

Cb

What is the correction factor (rating factor) for a semi-enclosed fuse to BS 3036 ?

1.75

0.725

0.5

0.575

When calculating the size of a live conductor, if there are no 'factors' to consider - what minimum current rating MUST the cable be capable of supporting ?

Protective device rating

design current of the equipment being supplied

32 amps

Iz

What is the function of this formula ' ? = mV/A/m ?

volts drop calculation

Total earth loop impedance calculation

(R1+R2) calculation

Ze calculation

What is the maximum disconnection time for a 230v AC circuit supplying fixed equipment not exceeding 32A, on a TT system ?

0.1s

0.2s

0.4s

5s

What is the maximum volts drop on a non-lighting circuit ?

2%

5%

3%

4%

What is the maximum volts drop on a lighting circuit ?

2%

3%

5%

4%

What is the disconnection time for a 230v AC circuit supplying sockets not exceeding 32A, on a TN system ?

5 seconds

0.5 seconds

0.4 seconds

2 seconds

What is the disconnection time for a 230v AC circuit supplying fixed equipment exceeding 32A, on a TN system ?

0.4 seconds

0.5 seconds

5 seconds

2 seconds

If a 'B' type RCBO to BSEN61009-1 - rated at 32A and 30mA, is installed in a TN system to protect a ring circuit in a detached garage, what is the maximum earth loop impedance allowed, to comply with BS7671:2018, with regard to 0.4sec disconnection time ?

1.37 ohms

1.5 ohms

1.09 ohms

1.44 ohms

How is the correct conduit size selected for installing different quantities of cables ?

Minimum 50% space as a general rule

Calculate area of conductors and deduct from conduit size

Select from tables in On-Site Guide by means of cable factors

Use a conduit selection formula

How close should the bonding connection of services pipework be to the corresponding water/gas meter in a domestic dwelling ?

100mm

850mm

600mm

350mm

What is the minimum size to be used for a extraneous bonding conductor (non PME) ?

10.0 sqmm

6.0 sqmm

2.5 sqmm

4 sqmm

What is the minimum size to be used for an exposed and unprotected supplementary bonding conductor connecting two extraneous conductive parts together??

10.0 sqmm

6.0 sqmm

2.5 sqmm

4 sqmm

What is the minimum size to be used for a protected supplementary bonding conductor connecting two extraneous conductive parts together?

10.0 sqmm

6.0 sqmm

2.5 sqmm

4 sqmm

What is the minimum c.s.a of the double-insulated 'tails' from your electricity meter to your consumers unit ?