OVERHEATING CABLE

[davy_owen_88]

On a slightly related topic, I noticed that the location field has been updated to include England, Wales, Ireland and Scotland. Unfortunately, when I tried changing mine to Wales after I click 'submit' it reverts back to UK.

 

[Softus]

many citizens of the UK who live in, or come from, parts of the UK which are not England, are very offended by the lazy mind which treats "UK" as equivalent to "England".

I don't treat England as being the entire UK, I just can't be bothered to keep asking people who post in "Electrics UK" if they live inside or outside England and Wales.

If it doesn't mean that I ignore the location completely - if someone asks, and/or if the OP makes it clear, then of course I take it into account.

It's not intended to be offensive, any more than those people who ask questions, knowing that Part P applies to them, but who have no intention of notifying, intend to be awkward and criminal.

There's a more important principle at stake than people's over-sensitivity, which is that the essence of Part P (being safety) applies to everyone who uses the England and Wales national grid, and England and Wales electrical components, and the England and Wales wiring regulations.

IMHO, things would be much simpler (in a better way) if the "Electrics Outside of the UK" (sic.) forum was deleted - very few topics in that forum ever achieve any kind of resolution. Then we could just have "Electrics" and there's be no risk of uptight people getting offended by lazy people.

 

[davy_owen_88]

There are still plenty of posts made to the 'Electrics Outside of the UK' forum though, and mixing them in with the UK lot would make things more confusing since most UK sparks don't know the answers to wiring regulations in Bulgaria.

I think a better solution would be to rename Electrics UK to "Electrics in England and Wales" and rename 'Electrics Outside of the UK' to "Electrics everywhere else" or something similar That way you save the ultra-sensitive peoples feelings and we can blindly spurt Part P warnings at everyone who dares to enter.

 

[Softus]

I'm all for some blind spurting.

 

[notyou]

As far as part p goes there is formal arrangement or indeed any requirement in any electrical installation test part p or not for load currents to be measured if a item is ce marked and duly rated.
The reason as to my uncertainty over the white one way wylex is that it is not ce marked and labelled.
To replace a cable that is burnt out and cut is a replacement again not part p, altering the characteristics of a cable by changing a bs3036 re wirable fuse of 30amp to 60898 mcb rated at 45 amp does 2 things firstly negates the need to de rate the ccc by 1.2 of load current and actually comply with regs with regard to load current being smaller than the protective devices. THus making everything much safer!
I've never changed the shower its always been on the wall, how can you replace a cable without connecting it to something, and then claim it has to be part p.
Or would you expect to put a couple of joint boxes in instead and wire in new bit of cable. surely it is safer to have te cable replaced instead of a jointed repair!

 

[Softus]

As far as part p goes there is formal arrangement or indeed any requirement in any electrical installation test part p or not for load currents to be measured if a item is ce marked and duly rated.

So let me get this straight.

1. You're registered to be able to test and self-certify under Part P.
2. You don't possess a clamp meter.
3. You're incapable of fault-finding your own installation without posting on an Internet forum.
4. You're incapable of answering a straight question.

I suspect that I'm not the only one who suspects there's something wrong there.

The reason as to my uncertainty over the white one way wylex is that it is not ce marked and labelled.
To replace a cable that is burnt out and cut is a replacement again not part p, altering the characteristics of a cable by changing a bs3036 re wirable fuse of 30amp to 60898 mcb rated at 45 amp does 2 things firstly negates the need to de rate the ccc by 1.2 of load current and actually comply with regs with regard to load current being smaller than the protective devices.

I don't think 1.2 is the right correction factor for rewireable fuses - where did you get that from?

THus making everything much safer!
I've never changed the shower its always been on the wall, how can you replace a cable without connecting it to something, and then claim it has to be part p.

Er, eh?

Or would you expect to put a couple of joint boxes in instead and wire in new bit of cable. surely it is safer to have te cable replaced instead of a jointed repair!

Clearly. I can hardly believe you have to ask.

 

[notyou]

1 yes
2 clamp meter never had the need to use one but I'm going to get one, and again there is no need to do any current load tests for a part P. Fault finding is different
3 I'm totally puzzled by this situation not seen anything like it before Iknow the cables OK so why should it overheat and seeking a bit of friendly advice is no bad thing is that not what a forum is about. DUH!
4 what is your straight question?
5 cable correction factor IEE on site guide page 115 (Cr) got me numbers mixed up its 0.725 apologies a lot in my head at the moment

Be polite to people you never know when you might see somthing you cant get your head round

 

[Softus]

OK; maybe I've assumed that someone who's registered wrt to Part P would be capable of, and tooled up for, yer basic single phase electrical fault-finding, but it seems that I'm wrong, so I'll back off.

However, one tip: you don't know that any one cable or component is "OK" unless the entire installation is working and safe. If you start believing that the problem is definitely not the cable (as you appear to), and not the termination (as you've claimed), then you've closed your mind to some of the possibilities already.

 

[ColJack]

correction factor for rewireable fuses is 0.725

if you've changed the fuse from 30 to a breaker for 45, then you have increased ccc of the cable required, not reduced it..

( all other correction factors have been ignored for the following.. )

the It of the cable when a 30A rewireable was used was 41.3A

It >= In/Cr = 30/0.725 = 41.3A

for 45A breaker then no Cr so It = In = 45A

but he is right in as much as you can replace the cable for a single circuit that is damaged even if it is in a special location.. PROVIDING that the CCC is the same and it follows the same route..

but as we've said, you changed the required CCC of the cable..


SIDE NOTE: do you "non-England" types recognise The Queen to be your Sovereign?

 

[Softus]

Sorry, I missed this one earlier:

4 what is your straight question?

Also, have you confirmed that this MCB is supplying only the shower?

Are you absolutely sure that the shower rating is 9.5kW?

is it in any way possible that the shower has been fitted with a 10.5kW can? Did you buy the shower? Was it in the house already? Has anyone ever 'mended' it?

 

[securespark]

But then I have always found this rule a tad ridiculiculiculous in that you could have a 9.5kW shower on 4mm² taking a really bad route. So as a DIY-er who may not know any better they could end up replacing a heat damaged cable with the same CSA & route????

 

[ColJack]

good point but isn't this covered by the tests that should be carried out?

shouldn't a PIR or an initial EIC spot this..

designed incorrectly?

I still think that a PIR should be mandatory before selling a house..

even if not legaly binding for the vendor to bring it up to scratch, then at least the buyer is made aware of any work that needs doing and can negotiate accordingly.

 

[securespark]

I'm all for some blind spurting.

Nurse! Bromide over here, quickly!

 

[empip]

Here lies a strange situation :-

The odd three paras from Part P of the Building regs quoted.

DESCRIPTIONS OF WORK WHERE NO BUILDING NOTICE
OR DEPOSIT OF FULL PLANS REQUIRED
1. Work consisting of;

... (b) replacing a damaged cable for a single circuit only;
No mention of 'like for like' or following same installation path, or rating of cable or anything else really.

(c) re-fixing or replacing enclosures of existing installation components, where the circuit protective measures are unaffected;
Specifically enclosures, this has the only mention of protection, apart from the next para (d), Look closely at the words... mechanical protection and changed thermal insulation ..... So if adding mechanical protection with no increased thermal insulation effects then no problem...

(d) providing mechanical protection to an existing fixed installation, where the circuit protective measures and current carrying capacity of conductors are unaffected by the increased thermal insulation.


There is less in the actual law than first meets the eye, or the imagination ! Certainly protection devices such as the fuse are not mentioned...

BTW There is one specific mention of 'the regs' ..... look for zones ! Para.4 Special locations...

 

[Softus]

Here lies a strange situation :-

That's somewhat debatable, since this discussion is routine on the "Electrics UK" forum.

However, the first noteworthy thing is that you seem to be reading an out of date copy of the BRs.
Have you seen SI 2006:0652?