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Good afternoon all. Am seeking some input.
I have been asked to carry out some work to a detached garage.
Garage power is presently supplied by 2.5mm T&E from a 16A MCB on the house (bungalow) consumer unit. Cable route is via loft, exiting behind eaves and suspended about 2 metres across to garage. There is one twin socket inside and an FCU for the lighting.
House CU is fairly modern, 7 circuits all protected by MCBs, but it has an RCD main switch, 100A, 30mA. TNCS supply.
The work consists of repositioning the twin socket, replacing batten holder with a flourescent fitting and adding an exterior twin socket for the pond pump, mower, strimmer, etc.
My issues are as follows:-
1) Present RCD main switch.
2) Present height of overhead cable is approx. 2.5 metres from ground level and I think it should ideally be 3 or 3.5 metres?
The regulations are not retrospective I know, (so maybe I can ignore issue 2), but the addition of the outdoor socket throws up the question of RCD main switch suitability as any problems with the garden equipment or pond pump malfunction would knock out supply to whole house. This brings me to issues 3, 4 & 5:-
3) Should I consider adapting/replacing the house CU, or choose another acceptable way of skinning this cat?
4) Just install an RCD board in garage? (Am not convinced this would prevent main CU trip though).
5) Install outdoor socket with integral RCD? (Anyone have experience of actual trip times for these and the confidence that discrimination would be achieved?).
Have tried to keep this post as brief as possible. Probably failed. Look forward to your comments.
I have been asked to carry out some work to a detached garage.
Garage power is presently supplied by 2.5mm T&E from a 16A MCB on the house (bungalow) consumer unit. Cable route is via loft, exiting behind eaves and suspended about 2 metres across to garage. There is one twin socket inside and an FCU for the lighting.
House CU is fairly modern, 7 circuits all protected by MCBs, but it has an RCD main switch, 100A, 30mA. TNCS supply.
The work consists of repositioning the twin socket, replacing batten holder with a flourescent fitting and adding an exterior twin socket for the pond pump, mower, strimmer, etc.
My issues are as follows:-
1) Present RCD main switch.
2) Present height of overhead cable is approx. 2.5 metres from ground level and I think it should ideally be 3 or 3.5 metres?
The regulations are not retrospective I know, (so maybe I can ignore issue 2), but the addition of the outdoor socket throws up the question of RCD main switch suitability as any problems with the garden equipment or pond pump malfunction would knock out supply to whole house. This brings me to issues 3, 4 & 5:-
3) Should I consider adapting/replacing the house CU, or choose another acceptable way of skinning this cat?
4) Just install an RCD board in garage? (Am not convinced this would prevent main CU trip though).
5) Install outdoor socket with integral RCD? (Anyone have experience of actual trip times for these and the confidence that discrimination would be achieved?).
Have tried to keep this post as brief as possible. Probably failed. Look forward to your comments.
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