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imigix

Active Member
are ther any out there that can tell me about domestic mains wireing and earth loops.

also potential between earth and neutral.
 

Sonic67

Banned
What do you want to know? Potential between earth and neutral should be zero.
 

imigix

Active Member
Thanks for your responce, could you please answer the following

My home as a single phase supply between live and neutral i have 235v

The same between live and earth

But between earth and neutral i have 16v

I know that neutral should be earthed at the supply and therefore at zero

I wondered if my prob. was on the supply side or could it be earth probs. in the house.

Am i right in thinking that to check earth loop resistance from the home to sub. station i would use a earth loop tester and that the max resistance should be 1.2 ohms.

I would be very gratefull for any info. and advice.
 

Sonic67

Banned
Can be a couple of things. Where are you testing? At the meter tails?

Some installations can read a few volts due to things plugged in. For instance if you have appliances plugged in to the sockets you are reading through them and they could be the problem and not the installation.

What earthing system do you have? Earth rod? The sheath on the armoured cable? What?
 

imigix

Active Member
Can be a couple of things. Where are you testing? At the meter tails?

Some installations can read a few volts due to things plugged in. For instance if you have appliances plugged in to the sockets you are reading through them and they could be the problem and not the installation.

What earthing system do you have? Earth rod? The sheath on the armoured cable? What?
I am testing at a socket

The earth i think is on the armoured cable, the supply cable comes to the YEB fuse and a green single lead goes off to the consumer unit.
 

Johnny Thunder

Novice Member
If you are reading a potential difference between neutral and earth, then you have a problem somewhere. As Sonic is implying, if your eathing arrangement is via a rod, you may have some resistance there.
Is the test meter reliable?

I would suspect that what you are reading, is the P.D across your actual test meter.

If you want to check external earth loop impedance, you will need the correct test device.
A standard resistance tester will not do this.

This type of problem his hard to diagnose on a forum, you may be wise to get someone in to check it.
 

Sonic67

Banned
If you are testing at a socket the problem can be anywhere on the installation. You need to disconnect everything plugged in and disconnect at the board and check individual circuits.

E.g if you have a faulty kettle (neutral-earth) and it is plugged into the installation then you will read that if you are testing at the sockets or on the meter tails. You'd need to unplug it to prevent it showing up or at least switch it off at the socket. Most sockets are double pole. If you are purely testing sockets then unplug everything and test at the board (though in theory you could test anywhere). Bear in mind any fuse spurs on the circuit would also have to be switched off as well.

I've had similar things in the past and it can be down to several things. Possibly a compression fault where a cable is compressed either because it's been jammed into a socket and the neutral cable is worn away at the back of the metal box or on the screw thread securing the socket front, or a cable has been nailed or trapped under something like a florrboard or also once where it was new cable and the very end of the cable had been bashed about and was then used.
 
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Dave

Distinguished Member
Contact your local electricity distribution network, they will come out and check it at the cutout.

If it's a problem with their system they will fix it for nowt.
 

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