Can you identify this mystery cable inside the laundry wall?

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kiwijunglist

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#247867 27-Feb-2019 19:34

We are renovating our laundry.

I've removed a patch of gib up high so I can install some additional bracing behind the gib to hang my clothes dryer up high in the laundry.

I removed the panel and found this mystery wire.

It's a bare multistranded twisted core copper wire. It travels along side a set of 240V cables that supply another part of the house and then it dives down through the wall towards the old laundry sink (1965).

I assume it's an earth cable. Does it attach to the pipes supplying the laundry tub? I'm moving the laundry tub towards the right hand side, it's not in the way of adding the bracing for the dryer, so I can leave it where it is, but if it is an earth wire for the plumbing does it need to stay in contact with the pipes and also make contact with the new pipes for the new set of taps?

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sparkz25

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#2188419 27-Feb-2019 19:45

How old is the house? It looks like it could be the old main earth or a bonding wire? Is there an earth pin outside the laundry?

chevrolux

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#2188434 27-Feb-2019 20:21

Yea looks like one of the earth bonds they would tie to the copper water pipe.

I'm sure a plumber would know what to do with it - if anything.

SomeoneSomewhere

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#2188435 27-Feb-2019 20:22

It's likely that it bonds the sink, not the tap plumbing. If you open the cupboard you can probably find the connection.

Newer rules do not require the sink itself to be bonded, but if you have conductive water piping, especially if it goes all the way into the ground, that should be bonded somewhere.

kiwijunglist

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#2188467 27-Feb-2019 21:13

the house is 1965.

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kiwijunglist

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#2188468 27-Feb-2019 21:13

What is the difference between bonded and earthed?

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SomeoneSomewhere

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#2188471 27-Feb-2019 21:18

Earthed is about operating a specific protection device, supplying the circuit associated with it. So the chassis of your washing machine is earthed, so that if a live wire comes loose and hits it, it blows a fuse or MCB. The earth only has to be sized to trip that circuit, not carry any other currents

Bonding is more about ensuring that there can't be a voltage difference between two points, which could be your neighbour having a stuffed earthing system and current going to your place via piping, or current leaking from somewhere else. Because it's not necessarily going to trip any protection and we don't know what circuit is providing the hypothetical current, the conductors have to be somewhat larger just in case.

larknz

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#2188480 27-Feb-2019 21:43

A house that age probably has galv steel or copper water pipes. The wire is probably a bond between the main switchboard and the pipework. Just be careful if you plan to disconnect it. There a small chance, especially if there is a fault with the main, that there will be a voltage difference between the wire snd the pipework. People have been killed doing this, although it is pretty rare.
Get someone who knows what they are doing if you need to disconnect it.

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sparkz25

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#2188483 27-Feb-2019 21:51

larknz: A house that age probably has galv steel or copper water pipes. The wire is probably a bond between the main switchboard and the pipework. Just be careful if you plan to disconnect it. There a small chance, especially if there is a fault with the main, that there will be a voltage difference between the wire snd the pipework. People have been killed doing this, although it is pretty rare.
Get someone who knows what they are doing if you need to disconnect it.

DO NOT DISCONNECT IT!!!!!

get a sparky to check it first as it could be the main earth for the house.

Back in the day if its was a galv pipe coming in to the property it would sometimes be used as the main earth instead of dropping a pin, so when the galv pipe finally gave out the property had no earth because the plumbers/council had replaced the galv pipe with pvc.

larknz

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#2188484 27-Feb-2019 21:57

sparkz25:
larknz: A house that age probably has galv steel or copper water pipes. The wire is probably a bond between the main switchboard and the pipework. Just be careful if you plan to disconnect it. There a small chance, especially if there is a fault with the main, that there will be a voltage difference between the wire snd the pipework. People have been killed doing this, although it is pretty rare.
Get someone who knows what they are doing if you need to disconnect it.

DO NOT DISCONNECT IT!!!!!

get a sparky to check it first as it could be the main earth for the house.

Back in the day if its was a galv pipe coming in to the property it would sometimes be used as the main earth instead of dropping a pin, so when the galv pipe finally gave out the property had no earth because the plumbers/council had replaced the galv pipe with pvc.

That is what I was implying when I said get someone who knows what they are doing. Maybe I should have been a bit more explicit, although I did mention that death was possible.

kiwijunglist

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#2188488 27-Feb-2019 22:04

I don't need to disconnect it. I think I'll just leave it be.

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