Mains switch keep switching off

[Harris786]

Hi All,

I went to see a job where mains switch kept switching off. The landlord wanted the old consume unit changing to a a new consume unit anyway. So I changed the consume unit but the mains switch still keeps switching off randomly.I would appreciate some advice please.

 

[Manator]

Is this a TT installation? Main switches do not randomly turn off unless you have major problems. Check to see if the main switch is a RCD.

 

[Harris786]

Yes it is TT system and main switch is not RCD. C/U is twin RCD and separate Double poll Main switch.

 

[ElectekAir]

The main switch is an isolator and cannot turn off by itself

 

[FozzyTime]

Are u sure it is a main switch you have installed? I heard a intresting percentage that 5% of all switch gear / breakers are sold faulty. Dont know the facts behind this but it may be true in your case.

 

[septiclecky]

The main switch is an isolator and cannot turn off by itself

Must have a ghost which goes round switching it off :slap :slap:slap:slap:slap:slap

 

[pewter]

We had a job with a mystery tripping breaker.

We split circuits, tested everything, changed a few cable runs, changed ballasts, fittings.

Myself and co worker made a few visits. Other crew on the firm made a few visits.

Eventually the other crew took it off that breaker and put the load elsewhere.

It still tripped the breaker with no load / circuits attached.

Our verdict was someone was messing around with it.

Got the lock fixed on the landlords intake area door and it never happened again.

 

[kme]

Well - you can rule out faulty kit...

If it used to do it,

then you changed it

and it still does it.

then I`d say there is some fault or other.

What were your test results from the board change. Which unit have you fitted? Do you have piccies? (we like piccies, we do!)

 

[Brian 157]

Never heard of this with a main switch, have known it with MCBs in TP boards where heat from adjacent MCBs caused thermal tripping and also RCBOs effected by walkie talkies & cordless phones. This was a problem with Memshield RCBOs in particular which MEM managed to counter.

 

[Harris786]

My mistake just rang back to landlord n he confirms that triping off from RCD, not from main switch. What it could be? Thanx for every ones help.

 

[kme]

My mistake just rang back to landlord n he confirms that triping off from RCD, not from main switch. What it could be? Thanx for every ones help. 

What were your test results from the board change.

Test results will show the problem - would have expected it to show up on dead tests when you did board change, TBH

 

[steptoe]

Borrowed neutral.?

 

[Steve3948]

Or crossed neutral, and you've reconnected it exactly as you found it, so problem still there.

This would mean however that that someone did something before you got involved or it would have been doing it from day 1.

 

[Harris786]

Landlord told me his builder worked for him as electrician. Can't do all dead tests cos CPC is from all lighting points, run insulation resistence test all circuits failed. Still RCD Is still switching off rendomly.

 

[Steve3948]

You must disconnect all the Neutrals from the neutral bar or you will get nowhere.

 

[Andy™]

run insulation resistence test all circuits failed. Still RCD Is still switching off rendomly.

maybe the RCD tripping is due to it failing IR testing.... just a suggestion...

 

[steptoe]

Landlord told me his builder worked for him as electrician. Can't do all dead tests cos CPC is from all lighting points,1 run insulation resistence test all circuits failed.2 Still RCD Is still switching off rendomly.

1 I have no idea what that means

2 thats why your RCD is tripping

 

[kme]

So, if I were to paraphrase, it`d go something like this:

" I have no idea what I`m doing, or how to test this properly. I didn`t do any testing when I did the board change, haven`t issued any certification or notified LABC. I thought that putting a new board in would stop this problem, and make me look good - but it hasn`t, and now the customer thinks I`m a div."

If that is what REALLY went on, then the short, simple answer is: you have to go and test it properly, to find the fault. Of course all the lighting has a CPC - did you think it wouldn`t, or summat?

If everything "failed an insulation test", WHY did you re-energise defective equipment?

Gawd `elp us!!!!

 

[MKS]

Did you break down the circuits after all circuits failed, to find out which said circuit is causing such problems?? I would have to agree with my learned gentlemen and ask why you have energized if IR has failed :-(

---------- Post Auto-Merged at 20:18 ---------- Previous post was made at 20:15 ----------

Can't do dead test cos of CPC? Are you saying you wrapped insulation tape around the tails whilst live and changed over the board?? Bwahahaha, I knew someone that did that, oh dear oh dear!!!

 

[Harris786]

After disconnecting neutral what shall I do?