6mm Cable Insulated Size

Hi all

Just a quick note/question regarding the external dimensions of 6mm T&E. Our kitchen is a single storey extension onto the original property, so the original cooker feed had been jointed under a bedroom floor. As I was splitting the kitchen onto a separate ring and running new power, lighting and earth cables, I decided to stick a fresh length of 6mm through for the sake of good form (and also to remove a section slightly damaged by recent plumbing works). As I am not "allowed" to do work "in" the kitchen per se, I have run the new cable as far as the kitchen loft and jointed to the old drop to the existing isolator for now. I have left enough spare in the loft so that it can be pulled down to a new isolator when we finally fix a layout for the room.

So, the question......

The external dimensions over the insulation for the new cable were significantly different (smaller) to the older cable. So much so that we ended up checking the cable strands to reassure ourselves that the new cable was actually 6mm! This cable is new colours , but was an "off-cut" and therefore didn't come on a labelled drum. The labelling on the cable itself (from memory) said something like BASEC

6004 4 2005. The number 4 in the middle was the concern - 4mm cable?

Anyway, having confirmed the conductor size at 6mm sq, why are the over-insulation dimensions so much smaller?

Thinner insulation to cut manufacuring costs? Thinner insulation to allow better heat disipation? Thinner insulation because the modern materials used are superior?

Anyone got any other ideas?

I would expect that the length of cable removed was about 20 years old.

TIA

Phil

Reply to
TheScullster
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There seems to have been a re-think about the thickness of insulation required (which would be mainly for mechanical protection) - the same has happened to car cable.

Reply to
Dave Plowman (News)

Pass. The conductors of 6 mm^2 have 7 strands of 1.04 mm dia. (7/1.04). For 4 mm^2 the stranding is 7/0.85.

Permitted tolerance - BS 6004:2000 Table 8 gives the following limits:

CSA Min. overall Max. overall --- ------------- ------------ 4 5.6 x 10.5 mm 7.2 x 13.0 mm 6 6.4 x 12.5 mm 8.0 x 15.0 mm

The 1995 version of the standard has the same sizes. I haven't got any earlier info, unless you want imperial cable sizes to BS 2004!

Reply to
Andy Wade

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