Am I being a snob, or is this actually dangerous

[Inteificio]

On a distribution board last week in a farm house, I saw 2 core 4mm SWA with the sheath terminated by having a couple of strands in a terminal block.

A photo would save a thousand words, but I found out on that day that my camera phone is not waterproof =-(

The other sparky on site said it is fine if the Zs is in, which I accepted at the time.

Then I got thinking, the Zs will make sure the fuse trips, but how can you guarantee conductor safety while the fuse is tripping?
We had a similar issue in our factory where a spark proved that a distribution circuit would blow in 4s, within the limit. However I pointed out the wires would be melting the insulation after 1s.

I can do the calcs to prove how hot that conductor will get, but that is not sparky level maths and I know the guy who installed it won't be able to do that.

So my question is:

When is it ever safe to terminate only a couple of strands of the armouring on SWA when it is being used as the CPC.

This is quite important as I am going to be politely confronting the guy, and I don't want to risk causing offence if I am wrong. I will be the first to admit domestic is not my speciality.

 

[Sparky_Ben]

Seems you generalised all sparkies there, in my opinion a good spark won't make excuses the work will be done right without problems to the regulations

 

[Inteificio]

I guess I did, no offence intended.

If one of my directors spots a mistake, you bet ya I have a good explanation ready!

If another sparky spots one, I thank them, learn from the experience and make sure I never do it again.

 

[Sparky_Ben]

That's ok then, true another set of eyes may spot something you might have missed

 

[Engineer54]

I really cant believe all this!! That SWA cable needs glanding, there is no ifs or buts about it!! There aren't any excuses this electrician can come up with to substantiate not glanding a SWA cable entering an enclose, especially a DB/CU... End off!!

 

[Engineer54]

To me that is a grey area. BS7671 is non-statutory, as long as I can demonstrate something is safe, then I am fine with it.

A lot of the stuff I deal with is very high temp, BS7671 doesn't cover what I do, so I always rationalise along the lines of, In the event of a fire can I stand up in front of a court room and explain without any doubt what I did was safe and why.

I didn't do the maths, just explained my method in case there was any interest. The reason I didn't do the math is that he can't; therefore he could not use that as defence. I wanted to know what he would say to the judge if there was a fire at my parents house.

Are you being serious here?? Grey area?? non-statutory, so it makes it all right to make up your own judgement on a clear non-compliant termination of a cable?? So you could turn round and say, that you can forget the BRB and make your own judgement on whether anything is safe or not!!! Who gives a dam about the math's here, or what an old dud of a judge would say!!!! ...You know that this termination is non-compliant and therefore not acceptable, what the hell else do you need to know, before you snag it!!

 

[Inteificio]

Which part of BS-7671 being not statutory, and therefore not being law, and therefore not having to be complied with literally to comply with the law do you disagree with?

You do not have to adhere to bs7671 to the letter to be legal, or to be safe.

However I would never terminate a cable like the above, I would consider it unsafe, hence me being on here asking more experienced people their opinion.

Regarding what the judge would say. If you have breached the BS7671 regs and there was an electrical fire, he is the guy who you would have to convince.

Personally if I was signing off that termination it would be a Cat 1 fail as a fire risk, but that is just me. I prefer my cat 1 fails as they cover my arse.

 

[wildgoose]

Why we don't use the same logic as your mate which only considers the resistance value and not CSA of the earth conductor??

If we did, then it means we could normally wire all the earths in 2mm cable. It would meet the ohmic value and save us heaps of money!!

It would also be totally inapropriate for dealing with any faults currents. Could this be just why main earths in houses are at 16mm???????????

 

[Guest123]

Rgardless of BS 7671 being statutory or not, if the issue remains after the final sign off, the installation will not comply as it will not be installed to BS 7671 as claimed.

510.3 refers to manufacturers instructions.

 

[telectrix]

and if those 2 strands were to snap due to mechanical stress, ask him what would then carry a fault current. beggars belief that anyone with basic electrical knowledge would even consider such an arrangement. it's like a plumber trying to plug a 22mm pipe with a 15mm stop-end. ( come to think of it, is this so-called electrician a retrained plumber?)

 

[Marvo]

I would also say that regardless of any reassurances by the installer it needs glanding on both ends. I would take a photo and send him a snag order, end of story. On something as blatant as this I wouldn't even quote the regs or be prepared to get into a discussion about it.

 

[netblindpaul]

BS7671 may not be statutory, but good old Part P is, and even if the work is not notifiable under pt P it still must comply, which requires it to comply with 7671, there in you have 4 reasons for non compliance already.
1. mechanical support or the lack of to relieve the stresses and strains on the connection
2. manuf instructions which will require the cable be correctly glanded
3. fault current calcs
4. the requirement in 7671 for suitable materials and workmanship

Oh and the same requirement in 4 above in building regs.

Get it sorted mate you know you want to!

 

[Guest112]

i dont understand the issue of glanding is he not capable?

 

[morph]

if the swa is the cpc then both ends need terminating in a suitable manner which is usually by means of a gland, another method may be appropiate

i assume the consumer unit is plastic and this is why he has not glanded it,
if he has used cleats then the cable is suported and so you cant use the mechanical support arguement
it is clearly a sloppy job,

 

[morph]

BS7671 may not be statutory, but good old Part P is, and even if the work is not notifiable under pt P it still must comply, which requires it to comply with 7671, there in you have 4 reasons for non compliance already.
1. mechanical support or the lack of to relieve the stresses and strains on the connection
2. manuf instructions which will require the cable be correctly glanded
3. fault current calcs
4. the requirement in 7671 for suitable materials and workmanship

Oh and the same requirement in 4 above in building regs.

Get it sorted mate you know you want to!

thats right regulation 7 i believe
as i said sloppy..

 

[netblindpaul]

You could probably also find something in the Construction Design & Management Regulations to have him on as well, they are statute law!