Old Electrical Wiring

[User]

 

[Globalti]

The electrician will throw up his hands in horror and tell you it needs rewiring and it does need rewiring, for sure, because mixing modern alterations with old wiring won't work. Look on it as an opportunity to get the house sorted and wired to a modern standard; you can get the electrician to make provision for all those modern conveniences like bathroom extractors, heated towel rail, underfloor heating in the utility or downstairs loo, heated mirrors, garden power socket and lights, 5 amp sockets in the lounge for table lamps that are controlled by one switch and so on.

 

[mybike]

Fuse box with rewirable fuses as well?

 

[Mile195]

That sounds like a very odd setup, and certainly sounds like it will need rewiring.

When I moved into my house all the electrical cable was lead-coated, with rubber insulation around the live and neutral. It still had an earth though despite being 80 years old.

It may be that the neutral and earth are linked instead. After all, neutral is just a massive earth rod at the substation. Massive bodge way of doing it, but the effect should be the same.

You could see if this is the case by testing for continuity between earth and neutral by (obviously) turning off the supply entirely (not just the circuit you're testing it on), set a multi-meter to measure resistance and see if you get continuity when you touch one lead to the bare end of an earth cable, and the other to a bare neutral (having obviously used an electricians screwdriver to make sure there is no voltage on either first for some reason!)
Everything in the house will need to be unplugged though as you could get continuity through an appliance somewhere. If you get continuity then the neutral is doubling as the earth. If you don't... well, it's not.

By the way I'm not an electrician. If you blow yourself up it's your lookout!

 

[Levo-Lon]

Mine was the same 30s house with some rewired parts..

it will need an upto date consumer box and the ground earh may be required ..new electric meters etc..all different to old set up now ..good sparks will put you straight..

 

[slowmotion]

If there's an earth point somewhere near the fusebox (ie near where the electricity company's cable comes into the building), measure the resistance between that point and the earth pins on sockets etc. You will need a long flying lead to do this. That should give you a very rough indication of whether or not the installation is a major liability.

 

[Mile195]

[QUOTE 4163303, member: 9609"]I had a property with that lead stuff in once, the rubber had all perished inside it, and fell to bits if you tried to do any thing, also had a huge fat bit of copper wire that was doing the job of the fuse ... LOL[/QUOTE]
Nice.... yes mine was much the same. I initially thought the place had been rewired in the 1960's. Obviously it didn't take too much investigation to realise that all they'd done in the 60's was put new sockets on to the old backplates.... hence why the one socket in each room was mounted on the skirting board! I still have the lead cable bagged up.. apparently lead's worth a fortune these days. One day I'll actually get round to taking it somewhere.

 

[slowmotion]

[QUOTE 4163321, member: 9609"]this is what is confusing me - there is no earth wires anywhere (seriously) I have used a long lead and tested the earth points at the sockets to the metalwork where the fuse board is and I am getting an excellent connection, but how do I know if the metal work in the fuse cupboard is connected to the "earth" I am a little concerned that it may have all been connected to the water pipes (rising main) but that all seems to have been altered with plastic pipes. (probably replacing old lead mains water pipe). Is the house just relying on the steel conduit within the walls as the earth ?[/QUOTE]
Can you see the incoming company cable where it goes into the 60/80/100 amp service fuse? In my ancient house, the earth conductor is connected to the steel armour of the incoming cable and this conductor branches out to an earth terminal before the service fuse.

 

[Over The Hill]

Assuming you go or a rewire, worth seeing if you can get a new wire up the metal conduit. This would be by firmly and smoothly attaching a new 3 core cable to what you have and pulling it up the conduit. If so then you could just work your way round replacing each length.
If not and it is a matter of starting again then better to just ignore what you have and put in new completely. There may be a better way of running behind skirting rather than following the old line up the wall.
Key point as it could make the job 10 times more difficult (or you don't want to accept an estimate for a long job where he does it the easy way). The full rewire will involve lots of re-decoration but pulling through new will not.

 

[slowmotion]

If you are worried about the existance of an earth, it's really very simple to bang in a copper earth rod or two in the garden and take some measurements.
https://www.tlc-direct.co.uk/Book/8.6.1.htm
Screwfix do four foot earth rods for about £3 each as well as cable clamps for about the same. I had to whack in four at a remote property in Cornwall before the installation cut the mustard. I got a fully qualified reliable sparks to sign off the job. Electrocution is something to take seriously.

 

[Hacienda71]

They used to wire buildings for lighting without earth's but using Pvc in the 60's. Current wiring have earth's. The old system works but is not current. Pvc wiring will not have perished so in theory is still perfectly functional. However you will be advised to rewire.

 

[slowmotion]

[QUOTE 4163442, member: 9609"]I have one of these copper earthing rods lying about somewhere - if i knock that into the ground, then test my earth from the three point sockets within the house,if I am getting a low resistance, would that show that the earth is good ? I would have thought that that would be a good test[/QUOTE]
It would show you if there was at least some kind of earth connection. I'm all for cutting corners, but this is not an area where bodging is a good idea. If the earth rod installation passes the tests, and if the electricity supply company allow such earthing arrangements, and if you get some Part P wallah to sprinkle holy water on it, then do it.
Banging in a 9mm copper rod and connecting some thick earthing cable is a trivial task.
BTW, please do try not to hit the incoming supply cable....

 

[jonesy]

As a start, I would suggest getting a simple socket tester (Screwfix do one for £7.99). This looks like a plug with LEDs in it. You stick it in each socket and the lights and a buzzer tell you whether there are wiring faults, in particular whether there is an earth connection. But the whole thing sounds rather dubious. At the least you will need a new distribution board with RCDs, and plumbing should be bonded to the earth connection at the board (not the same as using the plumbing as the earth connection!).

 

[mybike]

Am I not correct in thinking that modern installations have a distributed earth and the bonding to the plumbing is more a case of making the plumbing safe rather than providing an earth. I believe it's a nono to install a radio earth. It's possible with some systems to have a considerable potential between protective earth and an external ground rod.

 

[slowmotion]

Am I not correct in thinking that modern installations have a distributed earth and the bonding to the plumbing is more a case of making the plumbing safe rather than providing an earth. I believe it's a nono to install a radio earth. It's possible with some systems to have a considerable potential between protective earth and an external ground rod.

If you are miles from a substation, ground rods can be considerably better.