Blown Circuit

[GC]

I have an intermittent fault which causes the RCD to operate. The fault occurs every 2 - 3 weeks , never when we are at home and usually around the same time of day ( shown by the clock stopping)
Please could anyone advise possible causes & solutions ?

Thanks -GC

 

[securespark]

If same time of day and you are out, is there a timeclock switching something on? IE Boiler? Usually water using appliance is to blame.

 

[Millennium_Boy]

It COULD be your immersion heater, if it's on a timeswitch etc, they have a reputation for causing high protective conductor currents at times (due to presence of moisture etc).

 

[GC]

Thanks - I had a new combi boiler fitted about 6 months ago - maybe that is the problem.

I will ask an electricin to have a look.

 

[securespark]

Has the problem been apparent for 6 months?

 

[GC]

No - probably 3 / 4 months

 

[securespark]

Intermittent faults really hard to find - much easier when fault is always present, then you know what you're dealing with.

 

[ban-all-sheds]

Odd that it is so intermittent - every 2-3 weeks. Unless it's a combination of things, I can't think of anything that runs on that sort of cycle.

Except possibly auto-defrost on a fridge?

 

[plugwash]

i would suggest putting the fridge on the non-rcd side of the CU and seeing if that stops it

for a temporary connection just get an extention lead remove the plug and wire it into a 16A breaker in the non rcd side of the CU

if this stops the tripping then you should get your fridge looked into

 

[phil_ballard]

... presumably, a fridge is most likely to do this when it switches back on after auto defrost? when power is reapplied, and all the ice is now liquid? or do fridges do something active to defrost themselves these days?

 

[dingbat]

Talking of fridges, the disaster left by kitchen fitters that I corrected this week included a socket completely hidden behind a larder unit that was screwed to two other cabinets and a worktop and tiled up to. I ended up cutting a hole in the cupboard back to get at this socket, which is where the fridge was plugged in. As the poor homeowner commented, "How could I have turned it off to defrost?" How, indeed?

Do you think that kitchen fitters will even attempt to comply with Part P. I somehow doubt very much that they will even get to hear of it, as the Building Regulations clearly don't apply to them.

 

[securespark]

for a temporary connection just get an extention lead remove the plug and wire it into a 16A breaker in the non rcd side of the CU

PLEASE ensure that the flex is rated to 16A, and you have an effective earth connection.

if this stops the tripping then you should get your fridge looked into

"Oooh you've got a fridge full of beer.....!"


Dingbat-

I see this all the time.

I used to subcontract for a shed (kitchen electrics), and my standards were very high, as they are with all my jobs.

But I have seen some dreaful stuff, installed by big names under the banner "Professional Installation - No Worries". Indeed I used to troubleshoot other peoples jobs for the same shed....Oh dear!

Everthing wired as spurs, nothing on ring. No socket level with any other.
No grommets, a real pet hate of mine. N/E reversal, and N/L reversal.

Anything you care to mention, really. Sockets on lighting........

And they are ripoff merchants, too. One of my customers had a shed kitchen installed and the price was all-inclusive. However, he e-mailed me one day to tell me that the shed had insisted that because he had two rings in his kitchen, this was highly unsafe (not even on sep. phases), and they would have to quote for installing one new one......Yeah, right!

 

[securespark]

DELETED AS DUPLICATE

 

[plugwash]

PLEASE ensure that the flex is rated to 16A, and you have an effective earth connection.

if its just a single extention lead then it will have 13A (or whatever the plug fuse is) overcurrent protection at the destination anyway

and with protection from a 16A even with 1.25mm (13 amp) flex short cuircuit shouldn't be a problem

i agree that the earth should be well connected but this applies just as much when wiring a plug as when wiring direct to the CU

 

[dingbat]

Dingbat-

I see this all the time...

Trouble is it's not just the cowboys it's the customers as well. I'm going out shortly to try and convince a potential client that running a (8.5kW)shower off a five-amp BS3036 fuse is simply not going to work. Having seen another of his houses (oh no, Asian landlord alert) I just know, from what he's said, that there will be absolutely no bonding anywhere and probably an undersized main earth conductor. Chances are there will be many additional sockets, added willy-nilly and he will have put in multiple-lamp luminaires everywhere, downlighters and all kinds of sh*t. As for RCD's...

He's a real tightwad and I don't expect he'll accept my quote for doing it right. I'm taking a copy of the regs with me this time, along with some information about the forthcoming changes to building regs and a reminder of his obligations to his tenants.

You know, I almost hope he turns me down then one of his tenants fries in the shower... (Sorry, but, you know what it's like sometimes!)