Looking for some advice here not done a new install of tray before. What sort of cable should I be running on tray coming from a 3 ph board out to 16A commando sockets *5 and 5* 13A double sockets and lighting in a garage install. with a couple of machines like compressor etc.

Well, I guess I can give you an Old Skool answer - if you want tray, then typically that would stem from selecting SWA, MICC or "Hi Tuf" - ie using tray is a function of what cable you use, not the other way around.

If you want single insulated, then obviously conduit and trunking is the way to go - you could use it for T&E if you must - PVC or metal for the containment

Would I use T&E in a TP&N workshop environment? - no, it's house bashing cable

Regards

OMS

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Failure is always an option

pretty much my thoughts as well, I guess I needed reasurance I wasnt being to picky

I had this issue a few years ago - when doing an office to Pub conversion. The designers / clients consultants, for some reason chose twin and earth on tray as the installation method.

I, as the main electrical contractor, was not a happy chappie with this method, but could not find anywhere that particularly excluded this method. I had, prior to this job, never used twin and earth in a commercial environment, but it seems that it is a common installation method these days.

http://www.theiet.org/Forums/f...24557&highlight_key=y

I don't like it, but there's nothing to prevent it, bearing in mind the reduced earth size and ring circuits that tend to be extra long/big. If you can design around thoise issues, well T&E is OK I guess.

Old school answer: I agree with OHMS.

Hi OMS, if it's house bashing cable, any ideas why in the 6243 variety it's most commonly avaible in 3 phase colours?

The cores have to be indentified by something dont they?
They could make it with 2 browns and a blue for smoke alarms, but that cable wouldnt work for 2 way switching, so why bother, keep with brown black grey.

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry

For conversion method 2 way switching -

Regards

OMS

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Failure is always an option

I'm fairly confident with 2 way switching, but whats the conversion method?

I think 3 core+e came out before interlinked smokes, for 2 way switching theres always the cable positioning, ie, 1 to the side of the cpc which can be identified as the common?

Yeah, i was being a bit deliberate. I think OMS means conversion as in put a bit of sleeving on it.
I think relying on 1 to the left, 2 to the right of the cpc would be inviting disaster looking at the standard of some house installs.

The cores have to be identified somehow (have you ever used numbered flex or SWA= PAIN IN THE toolbox.

Could be worse. There are a few thousand houses a few miles up the road from me that use red white and blue colours in the 3 core and earth- a particular quirk of the builder and client at the time.

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry

Interesting how we read things differently - I took it to mean adding a 2nd switch to an existing 1-way setup.

- Andy.

Wasn't R-W-B the national standard before R-Y-B? Perhaps Norm remembers...?
- Andy.

Yes it was - in line with the coding that the DNO`s used.

What is says on the tin

take a basic 1 way lighting circuit, you have a switch feed and switch wire at the switch.

remove the switch, connect switch feed and switch wire to 1 and 2 on a two way switch, run a 3 core from there to a second 2 way switch conect to the second switch as well as conecting the common on both switches - hey presto, two way switching "converted" from one way switching.

Simples -

OMS

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Failure is always an option

Returns below parapet!

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Regards

Martyn.

Only a mediocre person is always at their best



www.electrical contractors uk.com

PVC or XLPE insulated circular multicore with drops in conduit is pretty standard, I specify this often for light industrial buildings. Garages, pump stations ect. Must be properly glanded.

SWA for heavy industrial, mines, nuclear plants etc

My fault for the diversion, sorry martyn, I thought OMS and the OP had sorted this out in the first 3 posts!

To the OP, as per what OMS said, probably trunking with conduit drops might be worth considering as more suitable for the purpose than tray.

To OMS, thanks for the lesson in switching, though it doesn't really explain why 3 phase colours cable is used, when the regs preference is to use conductors that are identifiable throughout their length (or does this not apply so much to sheathed cables?)- I guess it must just be one of those things that are done because the majority do it that way and have done for a long time, add in the wholesaler factor that they probably sell less multi-brown and so don't tend to stock it etc etc.

I simply don't know why it comes in 3 core with phase colours - I just threw the two way conversion method in as a defense for my claim that it's house bashing cable rather than something you'd want in a workshop environment -

Flat twin (and 3 core) insulated and sheathed (with bare CPC) is a particularly British thing - no one else really has a cable quite like it

Regards

OMS

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Failure is always an option

Bonsoir mes tous petits choux-fleurs,

Is it not simplement because we ave 'ow you say 'armonised with the French etc. and this is 'ow they colour cables in Europe?

Zs

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'The desk is a dangerous place from which to view the world.'
John Le Carre

On tray? I'm assuming SWA into besa then conduit drop out of besa? Doesn't this get a bit messy when several cables on the tray? Or have I missed something?!