RCD nuisance tripping.

Jeepers_Creepers

Ectophile said:

Another thing that can trip an RCD, though in theory it shouldn't, is a short current surge.  Fridges and freezers are culprits for that.  On their own, they are unlikely to cause a trip, but when combined with a background level of leakage, they might.

A possibility. But they have always happened between that mysterious 7.30 to 8am slot as far as I recall. (Actually, I think there may have been a mid-day incident too, before Christmas.)

fenwick458

Jeepers_Creepers said:

First I need to track down RCBOs for a MEM 2000... :-(    

you need Eaton RCBO's, they cost a fortune new, you'd be better off with a new consumer unit and pay an electrician to fit rather than buy brand 17 brand new Eaton RCBO's. second hand tested ones on Ebay for around £20 each but still quite rare

Jeepers_Creepers

Thanks - good advice.

FreeBear

fenwick458 said: you need Eaton RCBO's, they cost a fortune new

Eeeks.... £30 each from Screwfix...

I'd be tempted to get an Eaton RCD (from Screwfix), and if that doesn't cure the problem, take it back for a refund.

Rumour has it that Hagar MCB/RCBO/RCD will fit the MEM consumer unit - If you have a spare floating around, take it with you to an electrical wholesaler and compare the two.

Jeepers_Creepers

Thanks. Yes, I understand Hagar will fit - they certainly look the same.

Seems I can just about get them for around £15 a pop - occasionally new but usually second hand for that price.

Hence me not being bovvered about internal lighting circuits, doorbells, smokies - I'll focus on sockets, outdoors, kitchen in the first instance at least.

Anyhoo, fingers crossed - so far today it ha...

Ectophile

Jeepers_Creepers said:

fenwick458 said:

Jeepers_Creepers said:

I think I'll proceed with replacing the main RCD with a non-RCD type switch, and then swap half the MCBs for RCBOs to start with - all the socket circuits and some of the other rmost likely - or risky - other circuits, like outside lights. This would be a better setup anyway, so wouldn't be a waste.

that sounds like half of the circuits will end up with no RCD protection?
17 circuits is a lot, if that were my house I wouldn't bother with 17 RCBO's. I'd have all the sockets and lighting circuits on RCBO's, and the rest of the circuits spread across 2 RCD's.
but It does depend on what type of consumer unit you have, and the price and availability of parts for it

Yes, 17 circuits is nuts, but it's what I inherited - it's in a 20-space MEM 2000. I did add to the excessiveness myself since then by having a sole 20A MCB for the 4 sockets in the room I'm in now, converted from the attached garage, and possibly even a single one for just the lighting in here - 2 wall lights... Then there's a separate MCB for the doorbell (don't ask... Ok, it was because it used to supply an ancient 'Bell' porcelain & Bakelite trannie, so I kept it when I fitted a modern replacement), separate S and L circuits for the upstairs when it was converted, ditto for the new extension - you get the idea :-)    

I'm thinking there's some circuits that will just not require the added protection of an RCD - the lights in this room, the doorbell, for example - so will instead focus on the important ones first and hopefully ultimately do pretty much all of them.

First I need to track down RCBOs for a MEM 2000... :-(    

That wouldn't comply with modern standards.  That's going back to the 1990's.  These days, all circuits in a house should be on RCDs.

Jeepers_Creepers

Ah, good point, Exto - yes, it would be a step backwards... :-(  

Back to t'drawing board.

Risteard

FreeBear said:

fenwick458 said: you need Eaton RCBO's, they cost a fortune new

Eeeks.... £30 each from Screwfix...

I'd be tempted to get an Eaton RCD (from Screwfix), and if that doesn't cure the problem, take it back for a refund.

Rumour has it that Hagar MCB/RCBO/RCD will fit the MEM consumer unit - If you have a spare floating around, take it with you to an electrical wholesaler and compare the two.

You must not fit another manufacturer's parts into the assembly. This is a type tested assembly and can only be fitted with other parts if expressly permitted by the manufacturers or both sets of components. Otherwise you become, in law, the manufacturer of the assembly and must do the type testing yourself.

Risteard

Ectophile said:

These days, all circuits in a house should be on RCDs.

Not strictly true.

Jeepers_Creepers

Cheers Ris.

When I had a look at some weird tripping at my sis-in-law's house - 2007 vintage - that had a small (8-way or something) split CU - only half was RCD protected. (Turned out to have been caused by a metal kitchen utensil she'd inserted into her toaster rather than the utensil rack positioned immediately behind it...)

So, back to option one - replace the RCD with a switch, and fit RCBOs to the circuits most in need. :-)