garage Cu

jnybakers · Sep 11, 2012

hi guys
I am recently qualified and in the process of registering with elecsa.

as part of my assessment, i am installing a garage CU, 30m away from the main CU.

i intend on feeding it from a 32a mcb from the RCD side of the main CU
i will be running it with SWA and with a radial on 16a and lighting on 6a mcbs respectively to fees a couple of lights and 3 sockets.

my questions are:
1. is it ok to feed it from the 32a MCB
2. should i use 4mm or 6mm SWA
3. the customer has refused to pay for a trench digging as i advised it should be buried at leas 18". will it be ok to be run along a fence for some of the distance?
4. is it ok to feed the 16a and 6a mcbs for the radial and lighting respectively.
also he would like an out door socket near the main CU, I suggest a spur of f a ring final, but he wants it off the one going to the garage. can i feed the socket directly from the swa but with a fused spur?

any help will be appreciated just want to make sure i am doing the right thing for the assessment.

telectrix · Sep 11, 2012

hi guys
I am recently qualified and in the process of registering with elecsa.

as part of my assessment, i am installing a garage CU, 30m away from the main CU.

i intend on feeding it from a 32a mcb from the RCD side of the main CU
i will be running it with SWA and with a radial on 16a and lighting on 6a mcbs respectively to fees a couple of lights and 3 sockets.

my questions are:
1. is it ok to feed it from the 32a MCB. yes , but preferably non-RCD. put RCD in garage is preferable
2. should i use 4mm or 6mm SWA. use 6mm, in case of future increase in load.
3. the customer has refused to pay for a trench digging as i advised it should be buried at leas 18". will it be ok to be run along a fence for some of the distance? i would batten the fence with some timber across the posts and fix the SWA to that
4. is it ok to feed the 16a and 6a mcbs for the radial and lighting respectively.yes
also he would like an out door socket near the main CU, I suggest a spur of f a ring final, but he wants it off the one going to the garage. can i feed the socket directly from the swa but with a fused spur? not good practice. feed from the CU as a spur.

any help will be appreciated just want to make sure i am doing the right thing for the assessment

you have not said how you intend to earth the garage, and what is the present earthing arrangement.?.

Read more: http://www.electriciansforums.net/i...tallations/63264-garage-cu.html#ixzz268v9nTPq

jnybakers · Sep 11, 2012

telectrix said:
hi guys
I am recently qualified and in the process of registering with elecsa.

as part of my assessment, i am installing a garage CU, 30m away from the main CU.

i intend on feeding it from a 32a mcb from the RCD side of the main CU
i will be running it with SWA and with a radial on 16a and lighting on 6a mcbs respectively to fees a couple of lights and 3 sockets.

my questions are:
1. is it ok to feed it from the 32a MCB. yes , but preferably non-RCD. put RCD in garage is preferable
2. should i use 4mm or 6mm SWA. use 6mm, in case of future increase in load.
3. the customer has refused to pay for a trench digging as i advised it should be buried at leas 18". will it be ok to be run along a fence for some of the distance? i would batten the fence with some timber across the posts and fix the SWA to that
4. is it ok to feed the 16a and 6a mcbs for the radial and lighting respectively.yes
also he would like an out door socket near the main CU, I suggest a spur of f a ring final, but he wants it off the one going to the garage. can i feed the socket directly from the swa but with a fused spur? not good practice. feed from the CU as a spur.

any help will be appreciated just want to make sure i am doing the right thing for the assessment

you have not said how you intend to earth the garage, and what is the present earthing arrangement.?.

thanks alot for the speedy response telectrix,
the present earth arrangement is TNC-S
do you reckon a 3 core swa would be ok as long as the Ze value is within the acceptable range or should i go with making the garage TT by using an earth rod?

and on the main CU, both sides are covered by RCDs so i will split it 3 ways, 2 with RCDs and the 3rd without.

once again thanks a lot for the quick reply.