EARTH Problems

[Contax]

If I test LIVE connection with a test screw driver it lights dim, if I touch a metal pipe with other hand at same time it lights bright.
If I do same test on NEUTRAL it lights dim, touch a pipe light goes off.
EARTH acts same as NEUTRAL.
It's a bungalow I have recently purchased, none of the EARTH's have green sleeve over but I am going to fit sleeves to all these as I find with the junction box type of lighting circuit it is more messy than looping ceiling roses. All suggestions greatly appreciated as I want it safe before I call someone in to lay undergroung cable to garage.

 

[mapj1]

sounds like
When you are connected to the earthed pipe, the current through you increases and the light is brighter.

Either you or the neutral are slightly live, but the pipe, neutral and earth are at the same potential.

There are 2 possible reasons.

1) It is very possible you are picking up some induced field, and the wiring is fine, but

2) there is a small, but non-zero chance, that neutral, earth and pipe are all bonded together, but not really at 'true earth potential' If you can get a true earth voltage from outside (hammer a bit of pipe into the garden as a temporary 'spike') and can borrow a multi meter, you can measure the voltage between house wiring earth and terra-firma proper. More than 10volts RMS and I'd suggest the house earthing is either defective, or a very large earth fault current is flowing. Either of those two requires more than pedestrian knowledge to correct safely.
Don't wish to scare you but its worth getting it sounded out which it is, or standing with feet in a puddle using the outside tap may be very painful.

regards M.

 

[felix]

Is your driver a proper neon type or one of those things with a battery and LED that can also be used for testing fuses? A neon needs about 70volts to strike and I would be worried if I found this many volts on my earth wiring. Those LED things are liable to light up at the least provocation and, in my opinion, are fit only for fuse testing.

 

[Contax]

I used a standard neon type electrical screwdriver without battery, just put on terminal and earths through touching pen clip on handle.

Could it need bonding straps between copper pipes of hot water, cold water, gas pipe and central heating pipes then earth cable from bonding strap to consumer unit earth (old Mylex type with plug in trips) as water feed pipe to stop cock is plastic.

 

[felix]

I was really hoping that you weren't using a proper neon but ---

Since your pipes are plastic they will be bonded to your earth wires and these in turn may be floating free due to faulty wiring at your consumer unit. What puzzles me most is the neutral wire. This is normally tied to a good solid earth at the electricity substation. Your connection back to the substation must be intact or you would have no power.

Perhaps you are standing in a monumental electromagnetic field. Do you have pylons above your house or are you next door to a radio or TV mast?

Perhaps the wiring coming into your house really is at fault. Check with a meter between your earth or neutral wires and true earth, ie a spike in the ground, and if it shows enough to light a neon send for the electricity board. It's their problem.

 

[Damocles]

You have just demonstrated that your N and E are at the same potential. This is good.

Neons are quite good at demonstrating that there is some voltage somewhere. They are unfortunately very sensitive to induced voltages.

You have also demonstrated that you were at a different voltage to both N and L when you did the test. If you were reasonably insulated from true earth, then I would guess you were picking up an induced voltage from the live wiring by being near it. I think it is quite unlikely that there is a significant voltage on N if your electrics are working normally.

From the safety point of view it actually does not matter if N and the internal 'earth' wiring are not at true earth. Any metal supplies entering the house shuld be bonded together for eactly this reason. So that all earths inside the house are the same. And yours is also the same voltage as on the N. Which is all good.

So what was that about bonding? Should be earths connecting the supply pipes where they change to metal inside the house.