What size your CPC

[jibjob]

Hi Guys,

I have been asked to install a some lighting & sockets in a lean too come garage come workshop type of thing. I was going to do it in PVC conduit & make a proper job of it rather than surface clip T&E all over the place. I haven't done much in the way of circuit installation using this method, I'm planning to do lights in 1.5mm singles & sockets in 2.5mm. I was thinking of doing the socket radial CPC in 1.5mm, any of you guys do this or would you stick to same size CPC as L&N? Thought as it's a small install, 5 sockets max on 16a MCB it would be a cost effective use of 100m drum of 1.5mm G&Y.

 

[Baker1988]

Me personally I would stick to the same size as l and n if using singles but I'm sure it would still be OK if you use 1.5 CPC as that's what they use in twin and CPC cable

 

[trev]

Your cable selection calculations will tell you whether this is a viable method

 

[Plonker 3]

Depends what your cable calcs say it should be?

- - - Updated - - -

Damn Trev and his fast fingers

 

[spark 68]

The smallest size of a CPC if not an integral part of a cable is 2.5mm, I will look the reg up in a while.


edit: reg number 543.1.1, but there may be an exception see part (V) of that reg, there is a bit of a contradiction as below that it states that it shall be no less than 2.5mm if mechanically protected.

Typical bloody regs, lol

 

[Badged01]

and a 3rd consideration, table B7 of the OSG!

 

[telectrix]

or use galv. conduit and no need for a cpc cable.

 

[trev]

The smallest size of a CPC if not an integral part of a cable is 2.5mm, I will look the reg up in a while.

Sigh. You mean you haven't memorised them?

 

[spark 68]

lol see above Trev, I only know of that reg due to the 4mm requirement of adding seperate CPCs where not mechanically protected.

The smallest size of a CPC if not an integral part of a cable is 2.5mm, I will look the reg up in a while.


edit: reg number 543.1.1, but there may be an exception see part (V) of that reg, there is a bit of a contradiction as below that it states that it shall be no less than 2.5mm if mechanically protected.

Typical bloody regs, lol

 

[Badged01]

reg number 534.1.1, but there may be an exception see part (V) of that reg,

Which regs you quoting?

 

[spark 68]

Which regs you quoting?

oops my bad, lol, should be 543.1.1

Bloody IE 11 keeps missing characters out when I am typing, and I have to edit, I put the number edit in the wrong place, I will re-edit the earlier posts to correct

 

[Badged01]

Quoting regs will pull the chicks but even they sometimes check you're not bullsh*tting them :smile5:

 

[HandySparks]

The smallest size of a CPC if not an integral part of a cable is 2.5mm, I will look the reg up in a while.


edit: reg number 543.1.1, but there may be an exception see part (V) of that reg, there is a bit of a contradiction as below that it states that it shall be no less than 2.5mm if mechanically protected.

Typical bloody regs, lol

Surely 543.1.1 (v) allows the use of 1.5mm² cpc in PVC conduit (which is the case for the OP)?

Certainly for a lighting circuit.

 

[spark 68]

Surely 543.1.1 (v) allows the use of 1.5mm² cpc in PVC conduit (which is the case for the OP)?

Keep reading a bit further down lol

It contradicts itself

 

[HandySparks]

Keep reading a bit further down lol

It contradicts itself

Does it? If so, I can't see it.
Surely, you need to read the paragraph as a whole:

If the protective conductor:

(iii) is not an integral part of the cable, or

(iv) is not formed by conduit, ducting or trunking, or

(v) is not contained in an enclosure formed by a wiring system,

the cross-sectional area shall be not less than 2.5mm² copper equivalent if protection against mechanical damage is provided, and 4mm² copper equivalent if mechanical protection is not provided...


ie, if the cpc is in a cable, or in conduit or formed from metallic containment, the 2.5mm² minimum doesn't apply.