First time I've come across this fault

[Harryb]

Had a call, the lady had no power in her property.

Turn main switch off remove cover and test at incoming side of switch 230V.
Turn main switch on and at the other side of the main switch 50V. Faulty main switch I thought.
Turn off all RCD's and MCB's and have 230V where I found 50V previously. Turn RCD on and each MCB individually and when under load there is only 50V. L-E I have 230V at all times.

I could only think that there is a loose neutral and being underload losing the voltage?

 

[Marvo]

Sounds like a missing supply neutral and your first test on the incoming side was made using a digital tester with an astronomically high input impedance. If you redo the first test with an analogue tester you probably won't see anything close to 230v.

 

[CSP2012]

I agree.... Missing neutral. Could just be inside the db itself. I've had that before. Make sure everything is tight and in the terminals

 

[Harryb]

Spooky phantom voltage!! Damn digital!!!

Yeah everything was tight my side, OF COURSE

 

[GLENNSPARK]

well....we all know about Ze....what about Zpn then?
that would tell you if its supply side...wouldn`t it....

 

[ian.settle1]

well....we all know about Ze....what about Zpn then?
that would tell you if its supply side...wouldn`t it....

What is this when it is at home?

Some sort of Slavic word?

 

[snowhead]

Did you fix this or is the Power still OFF.?

under load there is only 50V. L-E I have 230V at all times.

I could only think that there is a loose neutral and being underload losing the voltage?

Can't possibly be the Neutral, you're not testing with it.

With all MCB / RCD turned on if you have 230 L-N and 230 L-E on the incoming to the main switch AND 50v L -E on outgoing side, it can only be the mainswitch failed on L.

 

[JeanGenie]

Yes I'd say it was a supply fault. Seen a similar fault on a 3 phase supply. Tested all good with main switch off, as soon as it was switched on and under load one of the phases dropped out. They were digging up the road after that.

 

[Harryb]

Not sure what has gone on I haven't been called back, it's a contract we have with social housing. Make safe and leave unless it can be fixed in an hour or so. Phoned the social housing and said it was a supply issue haven't heard back, they have arrangements for this she's probably in a void property newly refurbished, loving life

As far as tests go. (Kewtech 65) Main switch off Z(impedance) L-PE fine L-N fine. Main switch on (under load) no power and can't test

 

[Harryb]

Did you fix this or is the Power still OFF.?

under load there is only 50V. L-E I have 230V at all times.

I could only think that there is a loose neutral and being underload losing the voltage?

Can't possibly be the Neutral, you're not testing with it.

With all MCB / RCD turned on if you have 230 L-N and 230 L-E on the incoming to the main switch AND 50v L -E on outgoing side, it can only be the mainswitch failed on L.

50V. (Full stop & new sentence) L-E I have 230v at all times.

Read the bleeding post 3 times before replying those are the rules!!

 

[snowhead]

50V. (Full stop & new sentence)

50V. Full stop indicates shorten for VOLT

Sort the problem out yourself.

 

[Harryb]

Oooooooooo bad nights sleep?

 

[snowhead]

Oooooooooo bad nights sleep?

No, Just can't understand why I tried helping someone on what is really a BASIC electrical problem.

 

[GLENNSPARK]

What is this when it is at home?

Some sort of Slavic word?

Z phase-neutral...