Power Issue

[Dairyspark]

Went to a house last night and the bathroom lights weren't working, after some investigating I found that the lives at the previous switch were mixed up (one supply in common and supply to bathroom in with switched supply) sorted that but I'm still by getting power at the bathroom switch, when I put my test lamps into the live and earth they buzz to suggest a voltage but it's not giving me a reading, any ideas people?

Cheers

Bobby

 

[Andy™]

what tester are you using? my fluke will make a buzzing sound if high-ish continuity between probes, and sounds identical to the sound it makes if 1 probe is on a live

 

[Dairyspark]

I'm using a fluke T100 and I'll give more details, it's an ex council house (Scotland) upstairs lighting is done in black enamel conduit, bathroom light is the last in a radial, all other lights working, no power at light, switch or conduit box in loft where someone has tapped off for a smoke detector, also being tapped off the actual light is 2 wall mounted lights, no power at these either obv, I suggested to customer since it's only one room, I could re run new singles to the bathroom lights to elimate old wiring and possible people's mistakes previously, but I don't want to rewire the light and it still doesn't work lol

 

[New Venture!]

Any chance someone has been fiddling before they called you?

 

[kerching]

Bad earth at switch, possibly?

Just guessing

 

[ProDave]

Check the conduit runs.

Last time I had a fault like this, someone had stood on a length of conduit in the loft, which must have been under strain anyway, and it had snapped clean in half where a thread entered a box severing the cables inside and cutting off the feed to one light.

 

[Dairyspark]

Any chance someone has been fiddling before they called you?

A very high chance since the bedroom switch wire was in with the bathroom supply and thanks Prodave I'll check the conduit run on Monday afaik it goes from a box above bedroom straight then 90 then straight to bathroom box, Any chance it could be loss of neutral?

 

[ProDave]

Testing would easily confirm if it's loss of neutral rather than L, basic stuff really.

 

[steptoe]

have you got a neon?

 

[Dairyspark]

I'm just trying to think of a few possibilities I don't do a lot of fault finding and no I don't own a neon, thought those things were frowned upon lol

I'll also point out im still an Apprentice so be gentle haha

 

[kerching]

Neons are frowned upon by thoses who do not know what to do with them...in my personal and bigoted opinion!

 

[Dairyspark]

Care to give a quick user guide? Lol

 

[ProDave]

You need to do some dead testing.

Firstly, you are familiar with basic electrical circuits like a switch and a light, and understand how they work?

First thing to establish are you getting power to the light switch? Easiest way to do that is a r1+r2 test at the light switch.  If that's okay, with the switch turned on, do an r1+r2 at the light fitting.

If all that's okay you can do the same measurement but with N and you get Rn+r2.

If you don't understand circuits yet, and don't know about testing, then this would be a perfect opportunity for one of your mentors to come and fault find it with you explaining as they go what they are doing.

 

[Dairyspark]

I do understand the basics of circuits and I'll take the tester with me when I go back on Monday and I have highlighted the uselessness of my mentor in previous posts so I'm all alone on this one which why I have asked you fine fellows

 

[kerching]

Make sure on the R 1 and 2 tests that you have a good connection....AND that the leads are zeroed first if you want to get meaningful results

In the past i have found Screwit connectors in the conduit boxes which have been fitted by a Gorilla on steroids. Twisted so tight that the conductor had snapped just outside the connector!

Just saying

 

[OnOff]

I do understand the basics of circuits and I'll take the tester with me when I go back on Monday and I have highlighted the uselessness of my mentor in previous posts so I'm all alone on this one which why I have asked you fine fellows

One of the best, straight to the point books on the practical aspect of testing and inspection is to my mind the one by Brian Scadden. Clear diagrams and again only my opinion but well written. Well worth getting.

 

[Dairyspark]

Went back tonight and after further investigation without the home owner looking over my shoulder haha back up in the loft I found the bathroom supply came from the spare bedroom switch and not the master bedroom like i firt thought, opened up the spare room switch to find supply in L1, bathroom supply in C and room light switch wire in L2, sorted that, back up into the loft and finally getting power at the conduit box, power at the switch but not t light, so using the mft I long leaded the wire and it was tooshed, temp wire across from switch, hey presto light works lol, ran new switch wire and all was well!

Thanks for advice guys always much appreciated

 

[kerching]

I find it strange that homeowners rarely admit to having a fiddle...."not me, never touched it!"

Yet all the wires mystically disconnect themselves and then reconnect in different terminals!

Rule number one......always prove dead

Rule number two ....NEVER believe what the customer tells you!...listen to it, remeber it then act accordingly

Just advising

 

[ProDave]

In what way was the wire "tooshed"?

Did you pull the old wire out? Was it snapped or what?

 

[Dairyspark]

Metered it out and there was no continuity and as I started to pull it out it snapped very easily, so rest of the wire was removed and a new one installed