TRS wiring in house

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David321

488 posts

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#284248 9-Apr-2021 16:04

Hi all, my house was built in 1953 and has the old TRS wiring (the rubber stuff). I understand this is common in houses this age and they say getting houses re-wired to modern cable is a good idea for safety although this is well out of my budget.

In the past I have had an electrician add down lights to the kitchen and he tapped into the TRS wire which feeds the main kitchen light.

Now I have asked another sparky to move a light in my bedroom (which would require the cable to be extended) but he is saying they can not legally add to TRS wiring and that circuit would have to have new cable installed making the job a lot bigger and more costly than I was hoping.

My question is, is it actually illegal for a sparky to add to TRS wiring? Or is my sparkey after more money?

_David_

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#2690038 9-Apr-2021 16:16

I doubt there's many tradies looking to create work at the moment.

noroad

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#2690039 9-Apr-2021 16:17

TRS is a serious fire risk at this point, I remember replacing cracked and dangerous TRS 35 years ago. To be perfectly honest here I would highly recommend you do whatever you can to have a complete re-wire done, knowing what I do about it I would not sleep well at night in a house still actively using TRS.

wratterus

1687 posts

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#2690042 9-Apr-2021 16:24

Pretty sure it is illegal to add to a circuit that is using it but not 100% on that. It's certainly not sensible to. It needs to be replaced back to the fuse board for that circuit. Basically the house needs a re-wire. If you find some of that wire and give it a shake, it will probably disintegrate in your hands. It's scary.

Fred99

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#2690044 9-Apr-2021 16:29

Apart from the fire/electrocution risk with old TRS, I don't think it's allowed to add an extension & new fitting to a lighting circuit without an earth (since 1990-something). Old lighting circuits probably won't have an earth. If they're going to have to run an earth wire, may as well run new cable from the switchboard. They probably have to add an RCD to protect the circuit as well.

lxsw20

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#2690059 9-Apr-2021 16:32

TRS is awful, and I don't blame the sparky for not wanting to touch it. You do need a rewire if you have TRS. When I brought my place 5 years ago they asked for proof of a rewire as they wouldn't insure (or it would have been a much higher rate) if it had TRS.

Bung

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#2690072 9-Apr-2021 16:54

Insurance company policy is a law unto itself. They don't have to rely on electrical regs.

gregmcc

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#2690134 9-Apr-2021 17:48

off hand I can't think of a particular regulation that requires TRS to be replaced, what it comes down to is "IS it Electrically unsafe?" generally it is a judgment call by your electrician, you only have to look at it the wrong way and the insulation falls off, your electrician is telling you that he will not tap in to an existing TRS circuit as he will not be able to leave it in a electrically safe condition, by law an electrician must leave his work electrically safe. Basically he is covering his butt and I would not blame him.

If the TRS is in poor condition you should explore the possibility of getting it replaced sooner than later, you have been made aware of the poor condition of your wiring, not doing anything about it will come back to bite you later. This is the kind of wiring that leads to house fires.

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SomeoneSomewhere

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#2690160 9-Apr-2021 18:26

I agree with the above that it is probably legal to extend a TRS circuit in principle, but the regs require extensions to be up to current rules (straight replacement does not). A new lighting point therefore needs an earth, even if it is a double insulated light.

New cable needs to be protected by modern circuit protection, not a rewirable fuse. Plug-in breakers, DIN rail breakers, Quicklag breakers, and proper HRC/cartridge fuses are all acceptable.\

Extensions to lighting circuits are not required to be RCD protected; this is an exception. Extensions to power circuits are.

Most sparkies won't want to terminate TRS; too much liability. When heat damaged, it literally crumbles in your hands. In my experience, the power circuits (particularly kitchen, range, hot water) are very bad whereas the lighting is usually OK and in some cases I'd be fine leaving it in for another few decades. It depends on the lighting loads.

A few examples:

Bung

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#2690299 10-Apr-2021 08:39

I pulled some old unused TRS out from under the house recently to clear the way for some ethernet. I hadn't seen TRS with a white outer layer on the sheath before and initially thought it was old TPS. Apart from the ends it looked to be in good condition. However on older houses that tended to be only 100m² or so by the time you've got into the attic or under the house to replace the crusty ends there'd only be a short length of the old cable left so no point.

cyril7

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#2690331 10-Apr-2021 09:21

Thing to note, along with brittle disintegrating rubber insulation the wire is often steel, not copper, so if you get a short due to the high resistance instead of blowing the fuse it just sits there heating till it ignites something.

Cyril

Bung

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#2690340 10-Apr-2021 09:43

Steel?? Are you sure it wasn't tinned copper? My 1st house was built during WW2 and that still had copper.

sparkz25

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#2690347 10-Apr-2021 09:49

As a sparky, I would say the exact same thing, its a rip and replace job, as soon you start messing with the TRS its literally like opening up a can of worms sometimes.

Just when you think you found a nice bit that you can work with, it all goes downhill from there as the next 1m is starting to deteriorate and when it goes it just crumbles in your hand!

as @gregmcc has said "If the TRS is in poor condition you should explore the possibility of getting it replaced sooner than later, you have been made aware of the poor condition of your wiring, not doing anything about it will come back to bite you later. This is the kind of wiring that leads to house fires."