Light Socket Shows 176 Volts

[JohnW2]

The OP is confident enough to understand what is meant by continuity

He very probably is - but I still genuinely don't understand what you meant by "...with the main switch on". Maybe it's just me and/or I'm having a bad day!

Kind Regards, John

 

[EFLImpudence]

There will only be continuity between N and E with the main switch on.

 

[PosiDave]

Ok thanks everyone i'm worried to do the load test ... Through fear the reading will then show zero.. With fear the neutral is cut somewhere. I will perform this test tomorrow and if zero volts shown will try to invest in an endoscopy thing to see for the sake of 40 pound and a few ceiling holes I can narrow down the issue, ,,,, just hope is doesn't get to the stage of ordering a plasterer in .. Kind regards again for the advice ... LIFE sort one problem out and another turns up

 

[EFLImpudence]

Have you checked the voltage between L & E at your cable?

It should be the same as L & N - 240V

 

[deadshort]

There will only be continuity between N and E with the main switch on.

Back to basics

Regards,

DS

 

[JohnW2]

There will only be continuity between N and E with the main switch on.

So you're talking about the 'main switch' in the CU?

If so, that's all very well with a TN-C-S installation. However, with TN-S (or TT), there is likely to be an appreciable (albeit small) AC potential difference between N and E (due to VD in the neutral conductor back to the tranny) - and goodness knows what effect that would have on a ({very} low voltage, DC) 'continuity measurement' with the average meter. In fact, some decent meters might even refuse to undertake a 'continuity' measurement if they detect an pd (particularly an AC one) between the probes.

If the purpose of the exercise is simply to determine whether the observed low L-N voltage is due to a discontinuity in the N conductor, as you have said, one really just needs to measure the L-E voltage and see if that is equally low - or, alternatively, measure the L-N voltage on load (should be close to zero if N is broken).

Kind Regards, John

 

[PosiDave]

Right couldn't,t wait so hooked up a bulb holder wired into end wires placed multimeter across bulb load and turned switch on and now zero volts
Removed and 176 back so looks like a neutral issue and further inspection required.. Pray an endoscope works so I don't take half the hallway ceiling down locating issue.. If I've stuck a drywall screw through it somehow Be sick as a pig hopefully a connector box up there as suggested and wired pulled etc.. Thanks all for comments - gutted but enlightened

 

[JohnW2]

Right couldn't,t wait so hooked up a bulb holder wired into end wires placed multimeter across bulb load and turned switch on and now zero volts ... Removed and 176 back so looks like a neutral issue and further inspection required.

Indeed so.

Pray an endoscope works so I don't take half the hallway ceiling down locating issue.

Unfortunately, even if an endoscope enabled you to identify the problem, I doubt very much that you'd be able to cure it endoscopically!

If I've stuck a drywall screw through it somehow Be sick as a pig hopefully a connector box up there as suggested and wired pulled etc.. Thanks all for comments - gutted but enlightened

It would be unusual, although obviously not impossible, for a screw to completely (or very nearly completely) sever one conductor and not do anything else 'interesting'. Some sort of loose/'pulled' connection would seem fairly high on the guess list.

Kind Regards, John

 

[sparkwright]

Really good recent wake consumer box fitted and no issues with lighting circuit and yes reading is with light switch turned on. Checked light switch unit which also is good.

Any chance the some of the porch wiring comes from here, with a failing connection or something here?

Before you start making holes.

 

[RF Lighting]

By which method is the light wired i.e. loop at the fitting, loop at the switch, joint box method, singles etc.

//www.diynot.com/wiki/Electrics:Single-way-lighting
This page has some great drawings (3rd section down) to help you identify your wiring method.

 

[PosiDave]

Haven't dug holes yet. So for info the wire coming out in porch is a 1.5 twin and earth. All intact when I inspected cable All ok pull out about 1.5 ft when you wiggle can hear it tapping ceiling in hallway and the light switch by front door has usual two wires coming down so must be a junction box up there somewhere hoping borescope or something will spot it so only dig out what I need from cieling ... Have seen £10 ebay 7mm cameras with 6 led any one tried these...???