Bare CPC's

[mark28118]

Am i right in thinking that anything over 6mm doesn't need to sleeved, weather it be in a panel or an enclosure. Can anyone point me in the right direction as to where to find it in BS7671 if i'm correct.

Thanks in advance

 

[spark 68]

543.3.100

 

[Engineer54]

Where did you pick up that bit of duff information from??

 

[spark 68]

Where did you pick up that bit of duff information from??

BS7671, the 100 in the reg number at the end indicates this is specific to the UK

 

[Engineer54]

BS7671 allows bare CPC's over 6mm in CU/DB's/ Panels etc??

 

[spark 68]

BS7671 allows bare CPC's over 6mm in CU/DB's/ Panels etc??

Yes, we have used bare braids* (above 6mm) for bonding doors,gland plates etc. on switch gear panels.

* pre-crimped by the manufacturer

 

[Engineer54]

Panel door bonding on electrical panels etc, and Gland plate bonding to an enclosure, with bare braids is i suppose acceptable if they are of a very short length... I must admit, i was thinking more along the lines of actual bare cable conductors. lol!! Been a very long time since i've seen that being permitted!!!! lol!!!

 

[mark28118]

Someone told it me, its a load of rubbish i take it then...

 

[spark 68]

I must admit E54,
that I have never seen 'bare cables' even above 6mm used in any containment with live conductors.

Braids, Earth bars and trunking/conduit yes, but bare cables no, these have always been either G/Y sheathed or sleeved, amourings on amoured cables are already sheathed, I suppose the only other bare CPC type cables would be MICC.

 

[spark 68]

Someone told it me, its a load of rubbish i take it then...

See reg No. 543.3.100 that I posted earlier.

 

[Engineer54]

I must admit E54,
that I have never seen 'bare cables' even above 6mm used in any containment with live conductors.

Braids, Earth bars and trunking/conduit yes, but bare cables no, these have always been either G/Y sheathed or sleeved, amourings on amoured cables are already sheathed, I suppose the only other bare CPC type cables would be MICC.

Even MICC wouldn't be found ''inside'' an electrical panel!! Earth bus bars is a good example but then you wouldn't call a switchboard earth bus bar a CPC, it' will usually be the installations MET or EMT.

See reg No. 534.3.100 that I posted earlier.

I rarely if ever, bring home reference publications from the office, so it will have to wait for the morning. ...if i remember!! lol!!

 

[spark 68]

here is the reg in full.

543.3.100 A protective conductor having a cross-sectional area up to and including 6mm^ shall be protected throughout by a covering at least equivalent to that provided by the insulation of a single core non-sheathed cable of appropriate size having a voltage rating of at least 450/750V, except for the following:

i) A protective conductor forming part of a multicore cable.

i) A metal conduit, metallic cable management system or other enclosure or electrically continuous support systemfor conductors, where used as a protective conductor.

Where the sheath of a cable incorporating an uninsulated protective conductor of cross-sectional area up to and including 6mm^ is removed adjacent to joints and terminations , the protective conductor shall be protected by insulating sleeving complying with BS EN 60684 series.

I made a typo in the previous post, it should be Reg. 543.3.100, the original reg I gave was correct.

 

[thebigcheese]

Edit: Slow fingers!

543.3.100 states
"A protective conductor having a cross-sectional area up to and including 6mm^2 shall be protected throughout by a covering at least equivalent to that provided by the insulation of a single-core non-sheathed cable......"

It goes on to list a few exceptions like where conduit is used but doesn't go on to say what should happen where the cpc exceeds 6mm^2.

 

[spark 68]

It took me bloody ages to type the reg out in full, 1 finger typing lol.

 

[mark28118]

I only ask because I'm currently working in afghanistan and we are basically going over alot of american work and faulting it to our regs, in their NEC code they allow bare CPC conductors but I got told to BS7671 anything over 6mm didn't need sleeveing. But guess they were wrong. Thanks for the quick reply's