Red 4 core and earth.

[safedepth]

Evening all, A short break from Children in Need during the news.

A friend at work has asked the following.

Can I (he) use some 4 core core and earth 2.5mm cable I've (he's) "acquired" to supply an outbuilding. It would be fed from a spare way in the cu and terminated in a jb of some description. 2 of the 4 cores would be fed from the mcb and 2 from the neutral busbar. The 4 cores would then be split, 2 feeding a power radial of maybe 2 sso's and the remaining 2 cores feeding a lighting cct. The earth would be split and would supply both cct's. My initial answer was no but i must admit when he asked why I could think of no specific reg. The earth being shared was the sticking point for me but why?

Anyone got any ideas?

As an aside, what might this cable he's got be for. He's in the RN like me but say's the cable was not from there, he's reluctant to tell me where.

It's pvc sheathed, 4 insulated cores, he can't remember what colours but not black, brown, grey and a bare core (cpc)?

Sorry it's long winded late on a drinking night. Here have one on me whilst you ponder it. Guinness

 

[vandalay]

Would,nt the specific reg be the one about one circuit affecting another?Could he not just have a socket radial with fused spur going up to light.

 

[Apache]

Can't see it would matter if the cable was sheathed appropriate colours at both ends? Just like SWA. no?

 

[Evans Electric]

Its 5 core then ? Sounds like a 5 core PVC insul. cable without the SWA . We use it for light duty 3phNE on digital print engines etc. If you are burying it it needs to be SWA. You can't stick them all in a breaker and split them at the other end. Think best thing is to parallel them up 2 cores live/ 2 cores N / core 5 as E . Fit a spur next to socket at the other end ,3amp fuse for lights. Assume an RCD is being used .

That cable could be used if its not subject to mechanical damage , I suppose.

 

[safedepth]

Sorry all, should have said, he has actually already done the job. As he and I were both sceptical he decided to use 2 runs of T&E. It turned out to be only a 15 m run. The tight git!

Mr Evans, Sir, he was intending the paralleling method you speak of.

I had suggested what the socket radial with fused spur as well.

Regarding one cct affecting the other, this was where we each had our doubts.

Many thanks though. Guinness

 

[Evans Electric]

Bit different to wiring in submarines Safey, are you still in the Andrew.

 

[safedepth]

5 months and counting. Enjoyed almost all of it but 22 years is enough for me.

 

[Evans Electric]

Will you be joining the wacky and wonderful world of electrical contracting then , as you are on this Forum ?

Or finding a proper job !!!

22 years in a boat that sinks on purpose Eh!! Sod that! Applaud SmileyApplaud Smiley

 

[Mark2spark]

Each circuit should have it's own cpc. So one earth for two circuits is a no.

 

[binky]

I've always had a theory that the nearer a house is to the dockyard, the worse the electrics - didn't think it extended to the South Hams aswell :^O :^O:^O:^O. I'll be working in Salcombe again soon safedepth - if you want a quick visual on your friends handiwork PM me on here.

You didn't say what MCB he fitted it too.

 

[safedepth]

Binky, I know what you mean about dockyard distance and quality of work. In fact some work in it is a bit dodgy. I'm away from work this week, coincidentally to do my 2391 course. I'll see him on my return and find out if he wants it looking at. As Mr Evans suspects I am intending to join the ranks, officially early next year. How are things out there? I'm obviously hoping on picking up some of the business in your area as well, sorry. Hopefully there's enough to go around.

Mark, The separate cpc's was my first thought but couldn't think of a specific reg that said so and/or why.

Thankfully I haven't had to spend all 22 years underwater but I guess if you added it all up it would be a few years. Scary thought really. It used to make me laugh when people sympathised with these reality tv "stars" who go without contact for a few weeks, whilst sat outside in a garden jacuzzi.Applaud Smiley

 

[binky]

Work is thin at the moment but its Xmas, and that isn't unusual. As I've always said work is available to the honest and competent. If you don't mind working for peanuts I can teach you a few tricks.

 

[Mark2spark]

I'm not much of a reg head safedepth, but I think Chapter 54, if you can be bothered to wade through it, will give you the reg that 'bans' single cpc's to two circuits.

Although I do seem to remember doing a big seperate one in my learning years ?:|

So I've confused myself now! :_|

I think 543.1.2 says that calcs have to be done to show the csa is up to the pfc, so effectively 2 x 2.5mm circuits will need a 4.0mm single doing some quick sums in my head headbangPray

That'll do for me tho'!

:coat