Oh Dear

[BigJon]

Got called out to a fault in a portable building which had the mains installed by another "electrician"
Customer wanted to know why the sockets (RCBO protected )wouldnt work, after quick polarity test on the D.B I found Neutral bar to be live i.e reversed polarity.
It turned out a 4 core armour ( Old Colours )was supplying 2 consumer units side by side using 2 cores as 2 individual live, 1 core as neutral, common to the 2 consumer units and 1 core as the earth, again common,
So the ""electrician" doubled up to supply the portable building as below, sheath not earthed at any end either

 

[Spark123]

I don't follow how you say the old cable was connected, 2 cores as phase to where, both to the isolator? One neutral to the isolator? I can see where he has gone wrong using blue as phase in with the other blue and brown as neutral in with the black (or is that trick photography). Or is this the small SWA the supply cable? The original installer obviously didn't test anything before putting it into service either, what size is the new SWA? What size supply? Doesn't strike me as something any competent electrician would do, did you ask where he tied up his horse?

 

[BigJon]

sorry, there are 2 boards side by side both getting supplied by the 4 core armour.
2 cores supply the 1st DB (red and Black )
Black then loops through knockout in to adjacent DB ( one in pic ) on to Neutral along with the blue core for live, So the 4 core armour was supplying 2 consumer units off 2 circuits which were protected by 2 40 amp MCBs back at the Main 18 way D.B.
Looks like a 4mm armour he's used to supply the portable building aswell which aint good.

 

[Spark123]

So which is the CU in the pic? The one at the far end?

 

[BigJon]

yeah this is the one to the right of the other one.

I'm murder at describing things lol

 

[Spark123]

I see what you are getting at now, blue and black in and blue and brown out. Good old harmonization!! How long had it been like that? What were the test results like, how long SWA? Was it burried?

 

[BigJon]

apparently the portable just arrived this morning and the electrician installed the cable this afternoon then customer said he was going on to aberdeen so couldn't get him.
i'm employed by the portable building company so the mains wasn't really my/our responsablity but I glanded it in and doubled it in to a 20amp mcb and told customer to get the other electrician to put it on its own circuit, though think it went in one ear and out the other, all he was caring about was getting his portable building up and running.
Think it was buried but to be honest couldnt see much as the torch batteries had just about given up and it was pitch black lol

 

[Spark123]

So it is a temporary supply? I take it you did the necessary tests on it?

 

[BigJon]

yep. EFLI, PSC taken at our consumer unit in the portable building. and ofcourse the RCD tests

 

[ColJack]

why for the love of god did he cut the black out of the 4 core and use the brown instead? if it's black and blue then use black and blue ffs...


this is why harmonisation was a bad idea... blue phase, black neutral... some idiot gets to do the other end and goes..
"oohh, i know this... blue is neutral and black is a phase colour... "


if you must use brown and blue, at least get it the right way round..

I think all portable buildings should have a socket and plug arrangement like a caravan..

 

[Spark123]

why for the love of god did he cut the black out of the 4 core and use the brown instead? if it's black and blue then use black and blue ffs...

I'll have to disagree with you entirely on that colour scheme. Blue in an old cable is phase and black neutral. In harmonised it it the opposite.

 

[plugwash]

So the 4 core armour was supplying 2 consumer units off 2 circuits which were protected by 2 40 amp MCBs back at the Main 18 way D.B

On different phases I hope.......

 

[plugwash]

I think all portable buildings should have a socket and plug arrangement like a caravan..

Plugs and sockets make sense for touring caravans because both the site wiring and the wiring in the caravan stay fixed for a long time but the vehicles move between sites on a regular basis.

For portacabin like structures IMO they make far less sense, the wiring arrangements will probablly be different at every site. There is also the issue of RCD protection (depending on how the buildings are used you may not want everything on the same RCD but you don't really want outdoor plugs and sockets not on RCD).

 

[ColJack]

i'm problably thinking more long term than you are..

most sites i've worked on are 6 months to 2 years and the cabins are set up in an compound away from the main build. used for on site storage and offices etc...