Burning cable, what should i do??

[plugwash]

its not beyond the realms of possibility that different suppliers are selling different stuff

can anyone here absoloutely confirm that they have 6mm with 2.5mm earth (ie measuring the diameter of individual wires with an accurate tool such as a vernier caliper and calculating the csa from that) and if so where you got the cable from?

 

[kavozzy]

its not beyond the realms of possibility that different suppliers are selling different stuff

can anyone here absoloutely confirm that they have 6mm with 2.5mm earth (ie measuring the diameter of individual wires with an accurate tool such as a vernier caliper and calculating the csa from that) and if so where you got the cable from?

Good point plugwash
I also used to believe that the earth conductors in T&E cable where one size down to that of the phase conductors,
But on measuring the resistance of the earthing conductor in my 50 metre roll of 6mm2 T&E cable (0.00741 ohms/metre) for 2.5mm2 cable, Total = 0.37 ohms, means that the earthing conductor is in fact 2.5mm2, And its a solid drawn conductor, Not stranded,

 

[moulton]

Hiya peeps, sorry, this is a 6mm cable, not 10mm, and the 2.5mm that I was referring to was the actual diameter of the copper wire cores inside it. It was a direct replacement for what was installed by 'Dolphin' showers.
I will upgrade to 10mm if this is advisable, and I'll say, I'm not a total incompetent DIYer, I have got qualifications, just haven't done it since college days, and now isn't my profession. Many thanks to all who have given advice.

 

[theshogun]

The iee on-site guide refers to 6.0mm as having a cpc of 2.5,this is on page 45 (conventional circuits).
In 18 years i have not come accross new 6.0mm with 4.0mmcpc .

 

[kavozzy]

The iee on-site guide refers to 6.0mm as having a cpc of 2.5,this is on page 45 (conventional circuits).
In 18 years i have not come accross new 6.0mm with 4.0mmcpc .

Perhaps FWL is using cable from another world
Just like the houses which never have BS88 service fuses

 

[L.Spark]

Perhaps FWL is using cable from another world

perhaps it's russian, Jim talk's as if he's certain, I have some here and would be willing to send you a sample Jim..

nevermind ey, life goes on, and perhaps theres some confussion as there often is on these forums

 

[ban-all-sheds]

..he phoned the IEE to ask the same question, they replied with EXACTLY the same information..cpc's in T&E are always one size down, they always have been and there are no plans to change this.....

.... the IEE says the same....I feel confident we are correct.

1) The OSG's tables of Conventional Circuits only list 6.0/2.5 cable

2) Paul Cook's Commentary reproduces the familiar table of R1 + R2 for different Phase and Protective sizes, but highlights the following combinations:

1/1
1.5/1.5
2.5/1.5
4/1.5
6/2.5
10/4
16/6

Annoyingly there is no explanation of the significance of the highlighting, but the OSG also lists the same combinations in its tables of conventional circuits. (It also lists 4/2.5)

3) I've just applied a vernier caliper gauge to the cpc of some 6mm² T/E and it has a diameter of between 1.7 & 1.8mm, i.e. a csa of between 2.27mm² and 2.54mm². It's old cable, BTW (18+ years).

 

[supersparks]

i have to agree, 6mm definatly has a 2.5mm earth (solid) at all times ive seen it.

and 10mm has a csa of 4mm.

no doubt here.

ive seen a table someware, might have been aei webby

 

[ban-all-sheds]

BAS..don't tell me what to post,

Let's see - I can't tell you what to post, but you can say to theshogun:

"Will you stop talking absolute s**** about 47A for 6mm..."

How does that work then?

you are trying to say I cannot read the effing tables

Yes.

You claim that you misread the post as saying Method 11 not Method 1. But you must also have misread the table in the regs in exactly the same way.

 

[Big_Spark]

I love this "convenient" posting by some here..

The OSG...Please see table 9A on page 158, this clearly lists THREE "flavours" of 6.0mm, one with 2.5mm as the cpc, one with 4.0mm as the cpc and one with 6.0mm as the cpc.

I would also refer you to the BICC cable ordering Guide which lists the following..

6242Y 70625: 6.0mm Phase Conductors: Bare Copper 2.5mm protective conductor
6242Y 70640: 6.0mm Phase Conductors: Bare Copper 4.0mm protective conductor
6242Y 70660: 6.0mm Phase Conductors: Bare Copper 6.0mm protective conductor

Note: 70625 has a solid copper protective conductor, 70640 and 70660 have a stranded 7 core protective conductor. 70660 is available to special order only in lenghts of 500m or greater.

This may help to explain some of the confusion as there would appear to be several flavours of 6mm T&E out there, they also list a similar table for 10mm and 16mm, strangley enough BICC also list 25mm T&E which I have never seen used.

I have only ever used 6mm with a stranded core, and always spec'ed this when ordering cable, so this could well be the reason why you Guys wee it with 2.5mm cpc and I and other have not. I tend to only use BICC or Pirelli cables..Irish driver etc is crap.

I would think the sheds buy the cheapest cable they can, which will be the 2.5mm cpc flavour. Selling multiple types of the same size would likely only cause confucion for B&Q et al.

I will accept that they do make 6.0mm with a 2.5mm cpc, I was not aware of this as I have said, but equally I accept that I was also partially wrong as well.

It would be interesting to see a circuit with this installed as calculated the cpc size required for the circuit to see whther it complies with the Regs, I can imagine that in some cases this is likely the case.

 

[ban-all-sheds]

I love this "convenient" posting by some here..

The OSG...Please see table 9A on page 158, this clearly lists THREE "flavours" of 6.0mm, one with 2.5mm as the cpc, one with 4.0mm as the cpc and one with 6.0mm as the cpc.

It's not "convenient posting" - that was the "familiar" table to which I referred, and if you care to take a look at it as Table 4I on p 85 of Paul Cook's Commentary you'll see that it highlights one phase/protective combination for each phase size from 1 to 16mm². I'd always assumed that the reason the table had other combinations was to cater for circuits wired in singles, or for cables where the cores were all the same size (e.g. SWA), and that the highlighted combinations were standard T/E cables.

I tend to only use BICC or Pirelli cables

I've not been able to track down a BICC (now a Pirelli brand) catalogue/guide, but with Pirelli branded cables, both the standard and LS0H ranges are only available in the "usual" sizes.

I would think the sheds buy the cheapest cable they can, which will be the 2.5mm cpc flavour. Selling multiple types of the same size would likely only cause confucion for B&Q et al.

Nah - it wouldn't confuse either the sheds or their customers - they wouldn't notice . Anyway - B&Q sell Pirelli - hardly the cheapest on the market.

I will accept that they do make 6.0mm with a 2.5mm cpc, I was not aware of this as I have said, but equally I accept that I was also partially wrong as well.

It looks like all the evidence points to 6/2.5 as being the one made, sold, and installed almost exclusively by everybody, at all points on the quality spectrum.

 

[Big_Spark]

My comments about the situation with the posters shower were valid and I stand by them.......

Ban, I will not get into a ****ing contest with you, the fact is they do make T&E with BOTH sizes of cpc, I accept that I was wrong in saying, or rather insinuating, they didn't, as I said in my previous post, but equally I was not totally wrong.

Some of this stems from the fact that most of the work I have done and still do tends to be heavy commercial or Industrial where the use of the larger cpc would invariably be required in order for the circuit to comply with disconnection times. This is as much force of habit as anything else, I stioll use 6mm for cross bonding even though 4mm is acceptable. The shorter circuits used in domestics will not need this lee way, I did some quick calcs this morning and the average shower circuit will still comply with 7671 with a 2.5mm cpc so long as the circuit does not exceed a certain length.

I will admit that I will take note of this conversation as there is a price difference between the two flavous of about £8 on the 50m reels and £14 for the 100m reels..not substantial sums, but better in mine that the wholesalers...

 

[ban-all-sheds]

Ban, I will not get into a p******g contest with you, the fact is they do make T&E with BOTH sizes of cpc, I accept that I was wrong in saying, or rather insinuating, they didn't, as I said in my previous post, but equally I was not totally wrong.

Not after any sort of contest - I guess we've arrived at the same point from opposite ends - I (and a bunch of others) were unaware of 6/4, and you were unaware of 6/2.5.

 

[mapj1]

Be glad we are one of the few countries in the world, and certainly the only one in the original Europe that allows reduced, non insulated earth cores in its final circuit cables. (by reduced I mean not the same Xsection as the live conductor) As well as allowing far higher transient voltages during a fault, than the V/2 from an equal potential division, this perculiarity of our wiring also allows us a remarkable ferocity of debate, which I'm sure is of very little use to the original poster.

He would be better advised to check the contacts at the ends of his cable where it enters the switch and shower casing, for evidence of tarnishing and overheating as its almost certainly a frying connection, and to use the bath or wash elsewhere until the fault has been properly resolved.

 

[dabaldie]

are we not going off topic?

anyway..i know 10mm cable is a pain to fit and bend and do anything with... but why do people not just (as i have) install 10mm cable for anything that is likely to require a lot of power and is a single spur....

fit 10mm for ANY shower install... then you can easily upgrade at a later date with a better shower..

and fit 10mm cable for your cooker (we had to... bloody hotpoint quad halogen , could probably got away with 6mm just.. but wanted to play safe)

Surely this is the best philosophy...? ok might cost a £1 more.. woopey doo.