Neutral-Earth Voltage 120V

[ebee]

The Old "Drummond" testers had some advantage if used with care.

Additionally the old homemade Plugtop three resistors and two neons might have some merit but not the most foolproof of things.

 

[SUNRAY]

Equally I'll not describe a number of my techniques but I too have loop Z kit.

As OP has 120V on fitting earths, that will show on a LED screwdriver with ease just by touching any exposed metal/screw attatched to it and that may be easier than getting to the fitting, possibly unscrewing it and attatching wires.

I'm not trying to negate any other testing technique.

However I'd still check for V before Ω... see https://www.diynot.com/diy/threads/drain-on-electric-power-supply.482573/#post-3907705 post #7 or https://www.diynot.com/diy/threads/a-real-moan-tonight.552183/ for such an examples why

 

[ericmark]

show on a LED screwdriver

Excellent idea, so simple, can't think why I did not think about it.

 

[RK_London]

The Earth isn’t connected back to the CU is my best interpretation of what’s being reported

That is correct - did a continuity test of earth from light fitting to fuse box and there is a break.

 

[RK_London]

You have a multimeter, right?

Turn off the main switch.

Get an extension lead, plug it in to a socket near this light fitting.

Set meter to continuity (low resistance).

Poke one probe into the extension lead’s earth hole.

Toch other probe on light’s earth.

There should be continuity, but presumably there won’t be.

Repeat at other light fittings and light switches. Work out the pattern.

Thanks - that's exactly what I am doing

 

[JohnW2]

As OP has 120V on fitting earths, that will show on a LED screwdriver with ease just by touching any exposed metal/screw attatched to it and that may be easier than getting to the fitting, possibly unscrewing it and attatching wires.

True, but as a 'warning' that may not be true of a neon screwdriver (which I suspect is what most of us have), since 120V is pretty close to the striking voltage of a neon.

 

[RK_London]

This is the problem, I have a loop impedance tester, so I just use that.

On the odd time I don't have one, I have to look around me, and decide what reference point is valid, no good using a radiator tap with plastic pipes for example. And found with mother's house it simply had no earth to whole house. How I don't know, as a lad I made an error line to earth and ruptured a 13 amp fuse, so it did have an earth, but hunting around the house, all bonded together, but no earth, only thing I could find was an earth stake from the old party line telephone.

Long story short assumed earth had been from water pipes, and new plastic water main resulted in no earth, house wired 1954. So got the DNO to give me a TN-C-S supply.

So without a loop impedance tester, or earth tester View attachment 405481View attachment 405483how does one start? Until found no earth in mother's house never even considered it would not be at the consumer unit. Old fuse box had already been changed to a consumer unit, but I could find no sign of either a DNO fuse, or an earth rod.

I can think of methods, like using an old tungsten bulb, but there would be some danger, and I am not willing to detail how I would do it for anyone to read, it could be a pre-1966 installation when earth was not always taken to the lights. But until @RK_London confirms that other outlets do not show a floating earth, then all tests with a multi-meter are invalid.

Next step is to check floating earths on other outlets.

House is almost 100yrs old...although I have lived here 30yrs and first time I have tested the earth. The light fitting is in a ceiling below loft and I realised I removed the water tank and pipes in loft a few years ago - maybe the earth was removed with the pipes. Will work through each outlet to figure out.

 

[Murdochcat]

That is correct - did a continuity test of earth from light fitting to fuse box and there is a break.

Thanks for the feedback.

Please note there are still people doing electrics who don’t think continuity of ALL cpcs on lightning circuits is necessary

 

[ericmark]

I have worked on a Robin tunnel boring machine which had delta 3 phase 220 volt, with no earth reference, and it is not something I want to repeat, good money, but really it was danger money, never done any other job as dangerous.

 

[ebee]

True, but as a 'warning' that may not be true of a neon screwdriver (which I suspect is what most of us have), since 120V is pretty close to the striking voltage of a neon.

DO NOT have a Neon Screwdriver (but if you dothen never admit it! )

 

[SUNRAY]

DO NOT have a Neon Screwdriver (but if you dothen never admit it! )

WHY NOT when they are such a useful piece of kit?

 

[JohnW2]

WHY NOT when they are such a useful piece of kit?

As I recently wrote, LED ones are probably better/safer, since they ought to be able to detect voltages which are too low for a neon screwdriver to detect, but nevertheless quite 'high' (and, in some contexts, potentially dangerous).

Having said that, I think all the ones I have are neon ones

 

[ebee]

Well Really! They have been Outlawed !!! Have you not seen that Picture of a Policeman with an Amnesty Bin for Neon Screwdrivers? S it must be true .

They were very popular in the 60s even with Electricians.
Drawbacks - Could not always be seen in strongish sunlight , could give you a false reading and could give you a belt if the resistor failed or if inside the handle got wet (A pal of mine did that after he shookit dryer then put it in his toolbox for a few days, OUCH, the twit LOL.
If used extremely carefully and sensibly yes they might have some merits plus --- take the neon and resistor out and could be useful size on some screws.

The tradition of DIYers and some sparkies getting a plugtop and drilling a couple of holes in the cover (The Plugtop Top!!!) for the two neons and mount three resistors inside as an early version of the socket quick check variety , mine was a Crabtree Plugtop (Hoh Damn, I`ve just admitted it!!).
Could be useful but I would not recommend them either.

The things we used to do

 

[JohnW2]

Well Really! They have been Outlawed !!! Have you not seen that Picture of a Policeman with an Amnesty Bin for Neon Screwdrivers? S it must be true .

If you say so

They were very popular in the 60s even with Electricians. .... Drawbacks - Could not always be seen in strongish sunlight , could give you a false reading and could give you a belt if the resistor failed or if inside the handle got wet

All theoretically true but, despite your pal's experience, I think only the first two of those drawbacks are even remotely common (and someone who uses a wet one is just as daft as the person who uses a wet 'VDE' screwdriver ).

If used extremely carefully and sensibly yes they might have some merits plus --- take the neon and resistor out and could be useful size on some screws.

They definitely have some uses, but should only be used by those who 'know what they are doing' and who are therefore aware of the drawbacks and limitations. I quite often use mine (with neon and resistor still in) as a screwdriver. They have the advantage that they tend to disintegrate before one over-tighten small screws!

The things we used to do

You might be amazed (but probably not surprised!) by some of the things which I (and undoubtedly a good few others) "still do"

Kind Regards, John

 

[ebee]

ou might be amazed (but probably not surprised!) by some of the things which I (and undoubtedly a good few others) "still do"

I think that I probably would not.

Atually could have written that line to you .

But some some people.......... ho some people ! ! ! ! ! ........................ Oh Dear