Tripping RCD: Installing RCBOs...?

[JohnD]

I suppose there must be something comparable to the Competent Persons scheme. Not everyone who calls himself an electrician will do. That was my point.

 

[martinxxxxxx]

I suppose there must be something comparable to the Competent Persons scheme.

Yes they do have building warrants but they would not come into play with this sort of work - te scope of them is much less than part p (sic)

Funny thing is you only need a building warrant if you are in a flat or your house is over 3 storeys, neither of which seem to apply here, and you only ever require them for new work or rewiring have a look on www.sbsa.gov.uk.

For fault finding there is not going to be a compliance issue at all.

But as with the rest of UK all electrical work should be covered by a Installation or Minor works Certificate (no laughing at the back please)

Not everyone who calls himself an electrician will do. That was my point.

It is important to try and get someone who has experience and qualifications, I'd be asking for at least the city and guides 2391, although that alone would not guarantee that they could do a good job faultfinding. It would be worth paying someone competent £50 for an hour than finding someone for £25 an hour that took all day to get a result or worse told you s/he could not find the fault.

 

[shortshrift]

JohnD - RCD adaptor... thanks, I'm sure that would make a useful fault-finding tool, and much cheaper than the earth-leakage clamp meters I was looking at.

martinxxxxxx - Have turned off the boiler for the time being (this is - as you point out - Argyll, though; will reconsider when the August snow and storms come). Not had any trips since. A spell of heavy rain now and still no trips would be moderately convincing. But for the moment not losing the computer in the middle of typing and the washing machine in the middle of a wash is helping my sanity. If things continue to point in this direction, I'll get the boiler checked and the CH pump replaced, which I anticipate at about £70 parts + £50 labour. Still thinking of putting in RCBOs as per original post to avoid losing fridge/freezer/heating if a security light gets damp or rodents gnaw a cable when I'm away, but it's no longer a priority if I can get to the bottom of the current trips.

 

[shortshrift]

I sometimes turn up old threads in a Google search - a question is asked, there's a bit of discussion, but the OP never comes back with the final resolution.

In that spirit: Called in the electricians, who tested the circuits with a multimeter [Hmm. Could have done that myself. I had asked the dispatcher if they had a megger before they came out; guess he didn't understand the question, but said "yes" anyway.], found nothing and replaced the RCD. The tripping continued.

Went on for about 2 months in total, once tripping 10 times in a day, once going 20 days without tripping (20 days, mind, with the fault still unresolved, making fault-finding by exclusion well nigh impossible).

Then, happily, the fault became permanent and exclusion became trivial. (Although this happened while I was away on holiday; my neighbour glumly reported that they couldn't reset the RCD, so out went the contents of the fridge.) The problem lay with a PC monitor, and on further examination there was a live-earth fault in the IEC lead. Which had signs of apparent corrosion and even with a DC multimeter showed a live-earth resistance of 14K-ish.

Interestingly/sadly, this fault would have shown when the electricians tested the circuit insulation resistance if we hadn't first gone round turning off the IT equipment at the socket so it wasn't disrupted by throwing the breakers!

Hadn't realized how much intermittently losing my PC, washing machine, fridge, heating, etc. with no idea of how much it was going to cost to resolve had been wearing me down until I fixed it last night and went to bed a happy man. Woke up 8 hours later to my cordless phone beeping about lost basestation and no display on the clock-radio. Totally crestfallen until I saw the whole neighbourhood had lost power (back now!). What are the odds?

 

[ban-all-sheds]

Interestingly/sadly, this fault would have shown when the electricians tested the circuit insulation resistance if we hadn't first gone round turning off the IT equipment at the socket so it wasn't disrupted by throwing the breakers!

In terms of IR testing, the reason for turning off/unplugging things is because they can either give false results (e.g. filtering capacitors in power supplies), or because the things might get damaged by being hit with 500V.

You have a point though that it wouldn't do any harm where appliances have a removeable cord to remove it at the appliance end, not the socket.

 

[securespark]

I have a Proteus consumer unit with 8 x 632B1 32A Type B MCBs and a 63/2/30T RCD.

Is that all you have??