White T&E - Advice on a rewire

[ohmagain]

On a complete refurbishment on a property to find all the cables are white twin and earth, this is a rental property so previous usage is unknown as the storage heaters was removed and heaters plugged into rings so at least a medium uneven loads over the last 10 years. I am recommending a reinstall while the access is available and if they decide to sell after renting it will be a selling point. The existing installation was tested 3 years ago and got an overall fair rating, I found a potentially lethal example of home DIY get around performed by the tenants.

As the kitchen is being moved around I have insisted on a complete back to the board circuit change on kitchen circuit and oven line.

Cables have been designated as over 30 years old and as far as I remember (and a little reading) white T&E has a designated life span of 25 years, whereas modern grey T&E has 55 years due to many improvements in the PVC insulations, and the removal of ingredients that make it tempting nibble for rodents.

I guess here I'm just looking for clarification and realise this is a personal opinion thing.

Thanks in advance and look forward to the debate

 

[Mottie]

I rewired my current house well before the year 2000 using white pvc cable. Just added to the kitchen circuit with spare cable I had left over from that time. I’m not doing it again!

 

[Murdochcat]

White twin and Earth will last far longer than you think.

The only way to establish the ongoing suitability of the installation is another EICR , but I would be surprised if it needs rewiring

 

[Adam_151]

I've never come across anything that suggests that white vs. grey pvc twin has different lifespans from one another.

Since colours were harmonised with the EU (2004), white twin is always LSF and grey PVC, before then, there was no scheme to it and PVC was available in both colours.

Up here in the midlands, white PVC cable used to be an indication of DIY work having been carried out, but I understand in the south of the country it was more normal for the wholesalers to stock white, and not just the sheds, whereas here they would only buy grey

25 Years is more like the lifespan of VIR, which was generally black outer sheath (there were some hybrid cables in the 60s with VIR cores and grey PVC outersheath though!). Which considering it had generally been phased out by about the mid 60's, means that with its 25 year lifespan, whats left in service is generally quite far past its sell by date!

 

[flameport]

g) white T&E has a designated life span of 25 years, whereas modern grey T&E has 55 years d

Most PVC insulation will last far longer than that, 80-100 years would not be unexpected. The colour of the outer covering is unrelated.
Plenty of PVC cables from the 1960s still in use and in good condition today.

Only exceptions being for mechanical damage, gross overloading resulting in continued heating far above the maximum temperature of 70C, or certain cables made around 1970 where the plasticiser leaches out of the PVC and reacts with the copper to form green slime. All of those will be immediately obvious from a visual inspection.

 

[ebee]

Agreed - my limited experience is that different local areas had differing opinions of what grey or white meant, in my area grey was viewed as proper and white as DIY but a few other areas the reverse was the perception. I always assumed it was a bit of a local folklore kind of thing and was more dependant on what the wholesalers had in at the time and in my local areas they almost always had mostly grey and perhaps a few white rolls. Sometimes even apologising for only having the unfavoured white stuff to hand at the moment.

Even though at college it was explained that either was just cable of different sheath colour but with no particular advantage or otherwise to either there were still some students who insisted that white was for DIY.

There again, my own particular view of ceiling roses was that the Volex brand of rose containing a simple 4 terminal strip connector was a blooming horrible cheap nssty bit of tat but some folk loved them. Some folk preffered the rock/ashley 104 with its big terminal red sleeve permanent L connection. I didnt like those much either apart from they they looked prettier once installed, providing you did not forget the halo!

 

[bernardgreen]

The main factor in cable life is the quality of the cable which varies from manufacturer to manufacturer.

 

[ebee]

Could i just add to that Bernard, also it loading, max loading and length of time, particularly thinking of rings in this regard. Loading one end particularly, some give no thought, just a little thought required notmassive deep thought and calculations . Some just do as a radial and bring the end back which negates any ring advantage and ages cabke more.

 

[ericmark]

White at one time was higher temp to grey the latter emulating the colour of original lead, but not all white is high temp, so unless marking on cables just need to class all the same.

The loading on ring finals if we follow the advice given can be reduced to safe limits by "(iii) connecting cookers, ovens and hobs with a rated power exceeding 2 kW on their own dedicated radial circuit" to be frank ovens can be over 3 kW so would use a radial for the oven, but highest user was the washer/drier or drier, with the use of heat pumps for the drying function this problem is reducing, but it is really down to how close the kitchen/utility room is to the consumer unit, if central on the ring worse case is a RBCO trips, only is near the origin is there really a problem.

I did find new 2.5 mm² cable showing signs of damage due to over heating in my dads old house, but the older 7/0.029 imperial cable feeding it showed no signs of damage were spurs had been taken from spurs. I tried correcting but was chasing my tail, and decided it did need a rewire.

This judgement as to if some DIY work has compromised the original install is hard. Be it non BS 1363 items into sockets i.e. lumps of plastic to hold the safety shutters open, or spurs of spurs is hard, I tend to trust 500 volt insulation tester maybe more than I should, but there is a balance go OTT on what needs doing and you loose the work, go to gentle and there may be faults show up later, all one can use is experience.

 

[Harry Bloomfield]

Up here in the midlands, white PVC cable used to be an indication of DIY work having been carried out, but I understand in the south of the country it was more normal for the wholesalers to stock white, and not just the sheds, whereas here they would only buy grey

Around the Yorkshire area, it was the electricity board who used white, that combined with the neatness, always identified their work.

 

[hllns]

If it was tested 3 years ago and was "fair" it's fine isn't it? Any more detail on the report at all?

 

[JohnW2]

The loading on ring finals if we follow the advice given can be reduced to safe limits by "(iii) connecting cookers, ovens and hobs with a rated power exceeding 2 kW on their own dedicated radial circuit" to be frank ovens can be over 3 kW so would use a radial for the oven, but highest user was the washer/drier or drier, with the use of heat pumps for the drying function this problem is reducing, but it is really down to how close the kitchen/utility room is to the consumer unit, if central on the ring worse case is a RBCO trips, only is near the origin is there really a problem.

... and, even then, i would suggest very unlikely to be a significant 'problem'....

If, as is very commonly the case, the ring in wired in Method C 2.5mm² T+E, then even 2 x 3kW loads (or 3 x 2kW loads) very near to one end of the ring would not overload any part of the cable.

 

[ebee]

Well yes i do not disagree with that,in essence, however even loading throughout the ring should be attempted in order to avoid overloading or large amounts of load bias even if not overloaded would be expected to enhance life of cables to nearly forever. Simple thoughts of a quick in yer head nature are usually all that are required or even back of a fag packet if you like. There is no need to make great reams of calculations to acheive this aim. Two simple rules cover its (providing that total ring overload has been dealt with) 1/ even spread around the ring and/or 2/ most loads around the middle one third of total ring length and then you should have a ring that lasts a long time and no particular portion aging much more rapidly than the remainder.

I would remind both ring supporters and ring loathers alike, both have pros both have cons, rings are not as fashionable as in previous years but are still being installed today. If they were to be banned from today there have already been millions of them installed and will still be in service for "millions of years to come" so we should be able to test/inspect them and add to/alter them for years to come whether we like them or not.

I am biased towards them due to my age and upbringing others are biased away from them them for similar reasons , doesn't mean I am right and they are wrong, it just means that we have differing viewpoints in the scheme of things.

I am quite used to installing loads of consumer units with rewireable fuses and no RCDs in sight, i never felt uncomfortable with them at the time where nowadays I would be a little bit so.
MCBs and RCDs or RCBOs, plus SPDs nowadays are the order of today in my opinion in general .

Would i drive a car without using a seat belt today? No not nowadays, they are usually a good idea, have I in the past? Yes more than a few times!

 

[securespark]

In the NW, it used to be grey was "pro" and the sheds sold white

But then 0HLS came in, with a white sheath....

 

[ebee]

In the NW, it used to be grey was "pro" and the sheds sold white

But then 0HLS came in, with a white sheath....

Yes indeed that was often the perception in the NW in my experience too but I was told that in some parts , notably the south, the opposite was true. I must say that i did meet some in the trade who considered that white was for the pro.