Brown/Brown twin and earth.

[GBDamo]

Looks very professional when used for switch drops but...

And I am braced for impact..

How do you know which is feed and return?

Installed a 12 gang grid switch and used Brown/Brown and when wiring up the switches was wondering if there is a trick to knowing which is which.

Was a bit of a faff but sorted it during dead testing today but thought, why isn't one core distinctively marked, or maybe a different colour, say blue?

 

[Pretty Mouth]

Looks very professional when used for switch drops but...

And I am braced for impact..

How do you know which is feed and return?

Installed a 12 gang grid switch and used Brown/Brown and when wiring up the switches was wondering if there is a trick to knowing which is which.

Was a bit of a faff but sorted it during dead testing today but thought, why isn't one core distinctively marked, or maybe a different colour, say blue?

If you must use brown/brown (pointless IMO), then there is indeed a trick. The writing stamped on the flat T+E sheath is in the same orientation, on the same side right down its entire length. You can figure out which conductor is which from that.

 

[GBDamo]

If you must use brown/brown (pointless IMO), then there is indeed a trick. The writing stamped on the flat T+E sheath is in the same orientation, on the same side right down its entire length. You can figure out which conductor is which from that.

Genius, and obvious.

 

[davesparks]

In part.

It matters that the feed is in the com to me, it's just pride.

Yes, you can flip the switch once it's all been powered up, or reterminate it.

I just like to have it right before energizing.

But you said half of the switches will be on at the top, and the other half on at the bottom.
That's got nothing to do with whether the feed is in the common or L1, the switch works exactly the same either way.

The switch will be upside down if it is connected incorrectly so that it is operating between the common and L2.
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Completely agree. It should be mandatory. No-one here would dream of using brown & blue for a switch drop.

Do you have twin brown in every type of cable over there?

I've only ever seen it in T&E type cable,

 

[James]

Only in twin and earth, multi core is normally phase colours, or either white or black with numbered cores.

 

[Risteard]

But you said half of the switches will be on at the top, and the other half on at the bottom.
That's got nothing to do with whether the feed is in the common or L1, the switch works exactly the same either way.

The switch will be upside down if it is connected incorrectly so that it is operating between the common and L2.
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Do you have twin brown in every type of cable over there?

I've only ever seen it in T&E type cable,

Just T&E. You can get a four core flex with brown, black, blue and green/yellow which is useful for dual element immersions though.

 

[davesparks]

Just T&E. You can get a four core flex with brown, black, blue and green/yellow which is useful for dual element immersions though.

So what do you do when using flexshield, SWA or similar and you are wiring a switch drop but you would never dream of using brown and blue for a switch drop?

 

[Risteard]

So what do you do when using flexshield, SWA or similar and you are wiring a switch drop but you would never dream of using brown and blue for a switch drop?

2 plate it. SWA isn't typically used for switch drops like that.

Across the border only 7 core cables and greater can be remarked.

 

[davesparks]

2 plate it. SWA isn't typically used for switch drops like that.

Across the border only 7 core cables and greater can be remarked.

So does that mean that any installation which uses insulated and sheathed cables other than T&E is effectively banned from using 3 plate wiring for lighting?

If you can't remark any cable less than 7 cores what do you about emergency lights, PIRs, thermostats, anything else that requires L, S/L and N?

 

[Risteard]

So does that mean that any installation which uses insulated and sheathed cables other than T&E is effectively banned from using 3 plate wiring for lighting?

If you can't remark any cable less than 7 cores what do you about emergency lights, PIRs, thermostats, anything else that requires L, S/L and N?

Typically many of those things would be wired in singles. But for some of the others, as I mentioned you can get four core cables with brown, black, blue and green/yellow cores. The black can be remarked brown with heatshrink sleeving as black is a phase colour.

Another common way with T&E is to run a PVC/PVC single brown alongside it.

For smokes there is a new cable called RD415 specifically for the purpose.

 

[davesparks]

Typically many of those things would be wired in singles. But for some of the others, as I mentioned you can get four core cables with brown, black, blue and green/yellow cores. The black can be remarked brown with heatshrink sleeving as black is a phase colour.

Another common way with T&E is to run a PVC/PVC single brown alongside it.

For smokes there is a new cable called RD415 specifically for the purpose.

I guess you just do things differently there as you've got used to this way of working, here I think we'd find it an absolute pain if that kind of rule was to be brought in.

 

[Risteard]

I guess you just do things differently there as you've got used to this way of working, here I think we'd find it an absolute pain if that kind of rule was to be brought in.

It's good in many ways, in that we don't see the unmarked blues as appear to be common in England, but it's probably fair to say that it can occasionally make things more awkward than they need be.

But it is what it is as the saying goes...

 

[ipf]

I guess you just do things differently there as you've got used to this way of working, here I think we'd find it an absolute pain if that kind of rule was to be brought in.

Got to agree there.
Obviously, there are pros and cons either way but I feel it's just a bit more pampering to those who haven't got the ability (basic) or knowledge (even more basic) to work their way out of such a tight corner as a twin cable with two cores. I know it makes it easier for future workers/users but I must admit, I don't really mind the odd 30 second enigma.

 

[pc1966]

Both the twin-brown and the brown/blue reuse for switched supplies have their up and downsides. Really it would be best of all if there was an accepted standard for marking the switched live cable that (a) shows it is live and (b) shows is it switched.

In the brown/brown case you don't immediately know which is which, in the brown/blue case (usually) the brown is permanent live and the blue switched. If you find it in a single switch as a dropper then it is clearly not going to be neutral, but in a junction box or before then it many be anything.

So my own vote would be for brown/blue with a bit of brown sleeving, but even then there is nothing in any standard standard to say the blue-sleeved-brown has to be the switched one

One comment on these forums is the French have a colour (orange? purple?) for switched live, but as they tend to use singles in flexible conduit they don't have the pain of finding 3 reels of the "wrong" sort of T&E in the van when you wanted a given combination.

For specific jobs such as smoke/fire alarms when you need heat rated cable and a signalling cable as well then the RD415 looks like the perfect solution.

 

[telectrix]

we never had these discussions when it was all red/black. anothe thing to blame on the IEE/EU/PC brigade/snowflakes/gender neutrals/aliens/EMF/government/Welsh/immigrants/feminists/ even Scousers.

 

[UNG]

Can't remember using the twin brown T&E but back in the days of twin red the cores were identified by either looking at the end of the cores one had a two layer insulation inner white with red over and the other core was solid red or alternatively one core had a raised rib line in the insulation
I assume the twin brown must be similarly identified as having to bell out every switch drop could get very time consuming compared to using standard T&E and sleeving the blue
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we never had these discussions when it was all red/black. anothe thing to blame on the IEE/EU/PC brigade/snowflakes/gender neutrals/aliens/EMF/government/Welsh/immigrants/feminists/ even Scousers.

Never had the internet and forums back then, we just got on with it