Earthing and Protection - disconnection times, protective devices, types of fault, fusing factors and calcs, abbreviations and terms. 15 randomised questions from a LARGE question bank.
identify the protective device that has the BEST 'fusing factor'
BS3036 devices
BS88 devices
BSEN60898 devices
BS1362 devices
identify the protective device that has a maximum 'fusing factor' of 1.5 times the device rating
BS88
BS3036
BS1362
BSEN60898
identify the protective device that has a fusing element that is made of silver, and which is able to protect against very large prospective short-circuit currents
BS3036
BS88
BS1362
BS1362
a protective device is 'rated' at 25A and has a 'fusing factor' of 1.25 calculate the 'fusing current'
31.25A
20A
26.25A
23.75A
a protective device has a 'rating' of 63A and a 'fusing factor' of 1.75 calculate the 'fusing current'
110.25A
64.75A
135.5A
80A
a protective device is 'rated' at 32A and has a 'fusing factor' of 1.5 calculate the 'fusing current'
48A
20A
40A
52A
a protective device has a 'fusing current' of 9A and a 'fusing factor' of 1.5 calculate the current 'rating' of the device
10A
5A
6A
13A
a protective device has a 'fusing current' of 180A and a 'fusing factor' of 1.8 calculate the current 'rating' of the device
200A
125A
100A
80A
a protective device has a 'fusing current' of 72.5A and a 'fusing factor' of 1.45 calculate the current 'rating' of the device
100A
63A
50A
80A
a protective device has a current 'rating' of 10A and a 'fusing current' of 20A calculate the 'fusing factor' for the device
2
0.5
1.5
1.25
a protective device has a current 'rating' of 13A and a 'fusing current' of 21.45A calculate the 'fusing factor' for the device
1.65
1.75
1.5
1.25
a protective device has a current 'rating' of 25A and a 'fusing current' of 32.5A calculate the 'fusing factor' for the device
1.3
1.75
1.5
1.25
identify the protective device which offers both earth-leakage AND overload protection
mcb
rcd
cb
rcbo
identify the protective device that offers good 'discrimination' when protecting circuits with very large inductive loads connected to it
type 'B' mcb
type 'C' mcb
type 'D' mcb
type 'E' mcb
if too many appliances are connected to a 4-way extension lead, what fault may result?
short-circuit fault
earth leakage fault
transient voltage fault
overload fault
what type of fault is a RCD designed to protect against
large overload faults
earth-leakage faults
short circuits between live and neutral
a nail hammered into a wall, shorting-out live and neutral
identify the BS number for a 'mcb'
BS88
BS1361
BSEN 60898
BSEN 61009
identify the maximum disconnection time for a 32A socket circuit on a TN earthing system
0.2s
5s
0.4s
0.5s
identify the maximum disconnection time for a 16A circuit supplying fixed connected equipment on a TN earthing system
0.2s
5s
0.4s
0.5s
identify the maximum disconnection time for a 40A circuit supplying fixed connected equipment on a TN earthing system
0.2s
0.5s
5s
0.5s
identify the maximum disconnection time for a 50A circuit supplying fixed connected equipment on a TT earthing system
0.2s
0.5s
1s
0.5s
identify the maximum disconnection time for a 16A distribution circuit on a TT earthing system
0.2s
0.5s
1s
0.5s
identify the maximum disconnection time for a 63A final circuit on a TN earthing system
1s
5s
0.4s
0.5s
identify the maximum disconnection time for a BSEN61009 RCD (non time-delayed) when tested at 100% of the rated tripping current
200mS
40mS
300mS
350mS
identify the maximum disconnection time for a BSEN61009 RCD (non time-delayed) when tested at 50% of the rated tripping current
200mS
device should not open
300mS
350mS
identify the maximum disconnection time for a BS7288 RCD protected (non time-delayed) fused connection unit (pre 2018) when tested at 100% of the rated tripping current
200mS
should not trip out
40mS
350mS
identify the correct term for an 'earth rod' as found on a TT earthing system
earth connection
earth bond
earth electrode
earth connection
identify the operating principle for a BS3036 device
magnetism only
thermal/magnetic
thermal only
current balance
identify the operating principle for a BSEN60898 device
magnetism only
thermal/magnetic
thermal only
current balance
identify the operating principle for a RCD
magnetism only
thermal/magnetic
thermal only
current balance
identify the BS number for a HRC fuse
BS3036
BS88
BSEN60898
BS1362
identify the BS number for a 'cartridge' fuse (same shape as found in a 13A plug)
BS3036
BS88
BSEN60898
BS1362
identify the BS number for a RCBO
BS3036
BS88
BSEN60898
BSEN61009
identify the BS number for a 'semi-enclosed' fuse
BS3036
BS88
BSEN60898
BSEN61009
Fusing Factor = ? / device rating identify the missing variable from this formula