Separate lives and neutrals through conduit

[amatureleccy]

I have just wired up my new workshop. The lighting circuit is standard grey 1.5 T&E. It is run through PVC box trunking conduit. I was telling a freind how difficult was getting the cable throught he conduit around the corners. He said that because it was going through conduit, I could have used separate reb and blue (live and neutrals) and would have found that much easier to run the cabling.

Is this true, can I just run the separate insulated wires through the conduit or does it have to be the double sheather grey cable with the red and blue (and earth) insulated wire on the inside.

Thanks

 

[Harry Bloomfield]

Yes, conduit is designed for singles, but they should both always follow exactly the same route in the conduit, so no eddy currents are created.

I assume you meant brown and blue above?

 

[BS3036]

Singles must also *stay* in conduit for their full length. They can't emerge just because it's convenient

 

[Harry Bloomfield]

Singles must also *stay* in conduit for their full length. They can't emerge just because it's convenient

Just to make that clear, if the conduit starts or comes to an end, before the switch back box, light fitting or etc. then you would need to have used T&E, rather than singles. All conduit ends would need to be properly attached and bushed.

 

[flameport]

can I just run the separate insulated wires through the conduit

Singles for conduit are sold for that purpose and are stranded.
It's NOT the single wires stripped out of a piece of T&E cable.

 

[amatureleccy]

OK thanks all. Good points made and understood.

The single wires have to terminate correct in their boxes.

 

[JohnD]

Singles for conduit are sold for that purpose and are stranded.
It's NOT the single wires stripped out of a piece of T&E cable.

what would be the ill-effects if you did?

 

[xm77]

Well it would be rather more difficult as singles stripped out from T&E are solid core while singles made for use in conduit are multicore so are more flexible to allow them to be pulled into conduit and round bends.

 

[Harry Bloomfield]

what would be the ill-effects if you did?

One of John's - Most likely nothing at all, except the cable will be exposed to potential mechanical damage and will lack the mechanical protection of the usually grey outer layer of T&E. It is simply not designed for use in any part of an installation, where it would not be entirely protected along it's full length by the likes of conduit, or trunking etc..

 

[BS3036]

what would be the ill-effects if you did?

For one thing the earth would not be insulated.

 

[SUNRAY]

Singles for conduit are sold for that purpose and are stranded.
It's NOT the single wires stripped out of a piece of T&E cable.

Can we not purchase solid singles anymore?

 

[JohnW2]

One of John's ...

.... is that a reference to me?

.... Most likely nothing at all, except the cable will be exposed to potential mechanical damage and will lack the mechanical protection of the usually grey outer layer of T&E.

The same would be essentially true of purpose-made 'proper singles', give or take the fact that mechanical damage during pull-in might be slightly more likely with (less-flexible and less 'shiny') solid core (single insulated) conductors.

It is simply not designed for use in any part of an installation, where it would not be entirely protected along it's full length by the likes of conduit, or trunking etc..

If I understand correctly, I think we are talking about a situation in which it would be "entirely protected along it's full length by the likes of conduit, or trunking etc." - the only discussion being as to whether (solid, insulated) conductors removed from T+E would be as acceptable as would be purpose-made (flexible) singles.

Merry Christmas to everyone reading this. In case some wonder why I am posting messages in the middle of Christmas Day, it's because we are essentially having a 'quiet day', having been forced to re-define Christmas Day as being next Tuesday, thanks to (Covid-related) isolation on the part of one of my daughters!!

I hope that most of you are managing to have a very enjoyable (maybe almost 'normal') Christmas Day, and one that has been less disrupted than mine!!

Kind Regards, John

 

[john4703]

Merry Christmas to everyone reading this. In case some wonder why I am posting messages in the middle of Christmas Day, it's because we are essentially having a 'quiet day', having been forced to re-define Christmas Day as being next Tuesday, thanks to (Covid-related) isolation on the part of one of my daughters!!

I hope that most of you are managing to have a very enjoyable (maybe almost 'normal') Christmas Day, and one that has been less disrupted than mine!!
Kind Regards, John

No matter what electrical differences people might have I wish you and your family all the best and hope that when your Christmas Day comes it is a really good day. Take care of your daughter and be happy.

 

[Harry Bloomfield]

.... is that a reference to me?

Yes, in that you seem to support the ignoring or the wiring Regs, based upon a purely personal view of risk assessment

 

[AndyPRK]

And the earth should be thicker in conduit. Or maybe that is just habit