in need of a rewire

[gordy71]

Hi guys, went to look at a rewire the other day and the customer is currently having a new bathroom fitted. the reason he called me was on the advice of the sparky wiring the bathroom who would not touch the wiring due to it being rubber insulated. As its so close to christmas i would not finish the rewire in time but want to help the customer out by getting some new wiring to the bathroom so it can be finished. So i gave him a price for new circuit to the loft space for other spark to finish bathroom plus upgrade of earthing, and tails which are currently only 10mm. I would henley block the tails and feed a garage style consumer unit for the new circuit so as to not be touching the old rubber cables and wooden fuse box. Does this sound ok as a temporary measure? i have got this job but may not get the rewire so i was wondering what steps i can take to cover myself if the customer doesnt end up getting the full rewire done? bad day explode :worship

 

[ProDave]

Sounds okay to me. You can't force someone to have a rewire, and your suggestion would ensure the new circuits for the new work would meet the regs, and the rest of the installation is "no less safe"

The only bit that concerns me is the 10mm tails. You don't want to be henley blocking into that really, at least not to feed the new mini CU.

So what I would do is new tails from the meter to henley block (cough, there was no seal, cough) new tails from henley to new mini CU and only the old 10mm tails from henley to old CU.

If tails from cut out to meter are 10mm as well, call DNO for a safety update which should be free, and (cough) point out to them the missing seal on the meter

Note on your EIC that the whole of the rest of the installation needs a requre in your opinion.

 

[gordy71]

Thanks dave, yes the current cable from the meter is 10mm t+e! I was going to renew tails from the meter but should i run new 25mm L + N to the old board? or leave it so i dont disturb the rubber cables like you say?

 

[Theorysparky]

no

leave the existing board alone

just worry about your bit

meter to henly block 25mm tails

and 10mm tails to your mini cu (if that size is ok)

 

[Larnacaman]

Why are people so afraid of disturbing TRS (rubber) cables??

so long as they haven't been subjected to prolonged exposure to heat or constant overloading they will be fine!! There biggest problem in installations, were the terminated ends being exposed to heat from incandescent light fittings etc, and/or persistent over-loadings, when the insulation would then become brittle....

Apart from that, they should be fine. I've actually re-used a removed TRS T&E cable in the past for a garage socket. I bet it's still there and functioning as safely as any PVC cable. ....Maybe even better, in the temps your having in the UK at the moment!! ..haha!!

I also have an extension lead (5yd/m), that must be now over 35 yrs old made from the same sort of TRS. The plug may have been changed a few times but the cable and the old 4 way square Duraplug extension socket is still going strong!!!

 

[Doc Hudson]

Why are people so afraid of disturbing TRS (rubber) cables??

I think they are probably just following the guidance from the back of building regulations approved document P, about older work practices that can be encountered. This suggests TRS should be tested at the earliest opportunity, but left undisturbed until replacement as they are beyond their normal working life.

Doc H.

 

[Manator]

This is true, any cables found should not as a rule be handled and tested for continued use to verify any possible dangers. All cables will have a life span that will expire at some time.

 

[Tooold]

I have tested and then changed cu on a rubber installation all results etc fine, test cert done for 3 years only. Old people and rewire would be too much. As customer said we been here 47 years and no one has died, feel a lot happier with new cu tho!

 

[Larnacaman]

I think they are probably just following the guidance from the back of building regulations approved document P, about older work practices that can be encountered. This suggests TRS should be tested at the earliest opportunity, but left undisturbed until replacement as they are beyond their normal working life.Doc H.

I can understand that, if talking about lighting points etc, ...But within the CU they shouldn't be any problem in the vast majority of cases. Only if particular circuits have been subjected to long term overloading.

Iv'e seen PVC cable installations in far worse condition in a CU than i have in TRS.

I don't know, but the more i hear about this latest Reg's, the more i get the impression that electricians aren't allowed to think for themselves anymore!!

I was always taught from way back when, that the Reg's and it's contents were but a guide to safe and good working practices, ... Not the be all and end all as a bible status... but a bible it now seems to have become these days!!!

I'm not sure if that's a good thing or a bad thing, to be totally honest, as i can see the pro's and con's of both sides!!! lol!!! :C ?:| :coat

 

[gordy71]

Why are people so afraid of disturbing TRS (rubber) cables??so long as they haven't been subjected to prolonged exposure to heat or constant overloading they will be fine!! There biggest problem in installations, were the terminated ends being exposed to heat from incandescent light fittings etc, and/or persistent over-loadings, when the insulation would then become brittle....

Apart from that, they should be fine. I've actually re-used a removed TRS T&E cable in the past for a garage socket. I bet it's still there and functioning as safely as any PVC cable. ....Maybe even better, in the temps your having in the UK at the moment!! ..haha!!

I also have an extension lead (5yd/m), that must be now over 35 yrs old made from the same sort of TRS. The plug may have been changed a few times but the cable and the old 4 way square Duraplug extension socket is still going strong!!!

Thanks for the input guys, i have come across TRS (what does this stand for?!) that has been in good condition and others that have crumbled in my hands. seeing as this house should have been rewired twice over i would rather not take the risk.

 

[Larnacaman]

TRS ...''Tough Rubber Sheathed'' ......

As i posted earlier, Yes you may very well find the insulation crumbling when you open up a lighting ceiling rose, or a socket outlet that has been abused by loading it up with adaptors and the like.( quite common, due to the lack of outlets on old installations) but you will rarely find that situation in a CU. Only if a particular circuit has been subjected to ongoing overloaded conditions....

 

[ProDave]

I'm just doing a rewire of what is probably the oldest installation I have yet found. All rubber cable, and the "original" installation just had a little tiny MEM fusebox with three 5A fuses. One for all the lights, and the other two each feeding a single 13A socket. No doubt they were originally 5A sockets.

That original wiring looks in good condition, though I haven't looked in the ceiling roses yet.

The installation was later upgraded by adding another similar MEM fusebox to feed a cooker a 13A double socket and water heater in the kitchen. That was all in PVC cable, the old imperial multi stranded version.

In spite of the age it all still tests okay, and for logistical reasons, I've fitted the new CU and temporarily connected the old circuits to the new CU just to give light and power while I proceed with the rewire. No issues at all with RCD tripping etc.

So as others say, old rubber cable can still be perfectly okay. Though in this case it's all getting ripped out and rewired.

A related question. Will the scrap merchants take rubber insulated wire? I know they will take PVC insulated copper wire, but what about rubber insulated?

 

[Sidewinder]

Larnacaman,

IMHO the change in the way the regs are viewed is to do more with standards of training.

When I started my apprenticeship, Industrial admittedly, and we had our own training school, however as I understood from my fellow college apprentices that were full time 1st yr in college they did much the same.

We had 4 trades, Fitter, Welder, Toolmaker, Electrician.

In the first year we all spent at least 6 weeks in each others area and could not move on until we had reached a certain standard.

That meant the sparks had to be able to oxy-acetylene weld & cut, arc weld, and MIG weld, make their own toolbox in sheet metal work and file a square in a square which fitted any of the 4 ways with less than 0.0015" gap at any point!

The welders had to be able to wide panels and connect things etc. & do basic electrical tests.

As per the fitters & toolmakers etc.

There was hydraulics, pneumatics, turning, milling, surface grinding, as well as the bench work in all trades and a certain amount of electronics for all too!

Obviously the sparks did more electronics.

We spent 4 days per week in the training school & 1 day per week in the local tech during term time, then 5 days out of term in the training school, for a full 52 weeks.

Then depending on the trade you specialised, however, even in your 2nd year there was certain cross over training.

The elect qual at the time was the 2360 IIRC.

 

[ProDave]

Sidewinder, who did you do your apprenticeship with? that sounds very much like mine, except we did 1 week out of 4 at college rather than 1 day a week.

 

[Sidewinder]

Pressed Steel Fisher mate, later to be known as Austin Rover Group!

I think it was pretty much the standard EITB apprenticeship form mid/late 70's early/mid 80's.

 

[ProDave]

Pressed Steel Fisher mate, later to be known as Austin Rover Group!I think it was pretty much the standard EITB apprenticeship form mid/late 70's early/mid 80's.

Well well, another Oxfordian. Mine was AERE Harwell, though I lived in Headington at the time.

 

[Sidewinder]

NO mate sorry not an Oxfordian, I'm WELSH born, bred & apprenticed!!!

There was more than one PSF & ARG plant remember!

 

[Larnacaman]

Very similar SideWinder, I did my training under sponsorship of FoMoCo.. Same sort of situation too, they had there own training school. Then onto a 4 year Sandwich Degree course.....

Though doing a bit cross training, nothing like as you described. What we did have to cover was all aspects of electrical training, Design office, Repair and Testing department, Maintenance area, Management etc etc...

When i look back, i must have spent more time training than a dammed doctor!! ...lol!!!

 

[Sidewinder]

Larnacaman,

I certainly have!

I have also spent a LOT of time working at FoMoCo sites across the UK!

 

[Larnacaman]

Where i was originally based Dagenham, Alas most is no longer there. I think one of the few factories left there is the Engine plant, and maybe the Forge. But the body plant and the Assembly plant are no-more, among many others!!! Most of the work went to Germany and Belgium...