cu change ok?

[cakey]

Hi ive got a job to install some garden lighting. Big 5 bed house that used to be a farm years ago and has a 3p+n supply. Though there is only one phase being used which feeds a sp+n meter then splits at henley block and supplies two fairly old cu's for the house and also a 60amp switch fuse that feeds a 3rd 4 way cu in an outhouse. No rcd protection anywhere so was going to put a 1way rcd unit fed from henley block for garden lights. But customer is now thinking about updating the cu's instead which is great though im wondering if it would be ok to do so with the way it is all coming off just one phase? I remember being told about having to balance the load on 3p evenly. Sorry if its a daft question but never really had to deal with 3p+n before. Thanks

 

[plugsandsparks]

A coupl of things spring to mind. Looks like the meter man will have to come out if you want to fire up anymore phases, assuming they are lit.
If the max demand is being met now and you are just adding some lighting then why bother.

 

[Engineer54]

How many circuits does this old 5 bed farm house have?? I think first off, it would be a good idea to do a load assessment on this supply.

Nice bit of metallic trunking there, shame that whoever wired it, saw fit to pass what looks like single tails through individual metal couplings...lol!! That should be at the top of your list of works to rectify...lol!!

 

[cakey]

There are about 20 circuits in total looking at the pics i took and it seems the majority of them are lighting. Will check the load out when i go back there. Customer said hed like it all to be made "tidy" but im sure when i quote for cu change hel go for the cheaper option.

 

[Guest55]

Looks about right for a farm lol ,
30 years of adding on stuff with no clear plan or assessment of the installation as a whole.
Anyways , what size is service fuse ?
If 100 amp , then with diversity you can run fairly big loadings from one phase so i wouldnt worry too much about 3 C.U. 's off 1 fuse.

 

[Guest55]

Also i think he'd benefit from a EICR before whacking in new boards ,
i guarantee there'll be plenty of nasties lurking about , just depends on what customer wants to pay for.

 

[cakey]

its 100amp service fuse. i would test all cirucits before changing boards, would be very suprised if everything was ok. As u say lots of stuffs been added on over the years so much so that il struggle to fit a small rcd board in. Was thinking maybe an option would be to perhaps change just one of the cu's and add new lights to that...

 

[cakey]

How many circuits does this old 5 bed farm house have?? I think first off, it would be a good idea to do a load assessment on this supply.

Nice bit of metallic trunking there, shame that whoever wired it, saw fit to pass what looks like single tails through individual metal couplings...lol!! That should be at the top of your list of works to rectify...lol!!

Not going to change cu now but out of interest is the fact that both neutral and line tails are passing through the same metal couplings a problem regarding electromagtic effects? Is it because there are a 4 pairs each going through individual couplings? If so how is this different to seperate t+e cables passing through seperate knockout holes in backbox? Thanks

 

[Engineer54]

Not going to change cu now but out of interest is the fact that both neutral and line tails are passing through the same metal couplings a problem regarding electromagtic effects? Is it because there are a 4 pairs each going through individual couplings? If so how is this different to seperate t+e cables passing through seperate knockout holes in backbox? Thanks

From the photo's, it looked like ''Single Tails'' passing through those couplings!! If both line and neutral are passing through each of the couplings, then that's fine!!! lol!! I have to blame aging eyesight!! lol!!

 

[Knobhead]

Your eyesight isn’t failing E54. That is something that needs sorting cakey to stop any problems with eddy currents. The tails can go through steel so long as a slot is cut between them. The slot stops currents circulating. A brass or plastic bush will protect from the edges of the trunking

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