Fault find or rewire?

[HappyHippyDad]

Just spent 4 hours tracing out a lighting circuit to try and find a fault.

I came across a switch that was switching the neutral. This threw me as I was getting 230V on the S/L (to earth) at the light when I switched the light off!!! I then realised the Neutral was being switched, which I haven't come across before.

Also have 0.02Mohms N-E (same circuit as above) which I've partially tracked down to mixture of 1 or 2 junction boxes hidden under floorboards, between 3 sets of lights.

All switches and lights were poorly wired (jumble of cables forced in, insulation breaking down, back boxes loose, filled with plaster and other mess).

I could tidy up the switches, spend 1/2 day taking up carpet and floorboards and perhaps find a single junction that solves all the problems. Or, I could spend 1/2 day taking up carpet and floorboards and get absolutely nowhere and then rewire anyway!

I'm erring towards a rewire of the 3 lights at switches in question. 2 x living room and 1 x landing.

What would you guys do?. Continue fault finding or partial re-wire of lighting circuit?

 

[Electro-tech]

I would rewire as you are already not happy with what you have found so far.

 

[James]

I would pull the circuit apart, all switches, fittings and junctions
IR test the cables
reuse the cables if ok
replace switches and junctions with new

 

[ipf]

I lean towards rewire, dependant on ease of isolation from the rest of the circuit.
Out of interest, what are the cable colours (old or new)?

 

[Dustydazzler]

As above , the actual cables might be re-usable , pull everything else apart and re-do

 

[HappyHippyDad]

I lean towards rewire, dependant on ease of isolation from the rest of the circuit.
Out of interest, what are the cable colours (old or new)?

old red and black - metric.

 

[Dustydazzler]

old red and black - metric.

Take the old red and black out as that stuff is worth a small fortune on Eday and rewire in cheap and nasty brown blue

 

[Vortigern]

Rewire it everytime. Just had a job, no cpc on one half of a flat. Could have gone in the double lofts looking for the fault. Could have taken ages as there were two lofts, insulation and carpet and boarding of a sort move it all and maybe just maybe find the fault. So I just bridged two lighting points with t&e used just the earth and hey presto problem solved in half an hour.

 

[timhoward]

When that happens I just tell the customer that I always seek to act in their best interests and it's better for both them and I to undertake a job of known length to remove many problems than to spend even more indeterminate time trying to find the damaged cable.
(You may be able to IR the switch wires and re-use them)

Funnily enough this video I've just watched seems strangely relevant....the usual language disclaimer applies, but it's a great example of logic going completely out the window when testing and searching for a needle in a haystack.

 

[UNG]

This is one of those jobs where a good cable tracer is worth it's weight had one a little while ago where the customer had put the floorboards down during a rewire the circuit in question started to trip the RCD occassionally the cable tracer identified the offending nail it was only a short length of cable so I just rewired it

I could tidy up the switches, spend 1/2 day taking up carpet and floorboards and perhaps find a single junction that solves all the problems. Or, I could spend 1/2 day taking up carpet and floorboards and get absolutely nowhere and then rewire anyway!

I'm erring towards a rewire of the 3 lights at switches in question. 2 x living room and 1 x landing.

Not quite understanding why you need to lift floorboards to locate the fault but to rewire you don't, if you lift the floorboards to locate the fault and subsequently need to rewire or partially rewire then you already have some of the work done for rewiring

 

[ferg]

Nobody gets it right all the time.
I would like to think that most of us get it right more than we get it wrong though.
IMHO if it's that close a call then it's likely there will be other little hidden treasures you haven't seen yet and rewiring will be the best option.
It's pretty clear you have the best interests of your client in mind so make a decision and then change your mind if needed