RCD question

[VisionSet]

On behalf of a mate:

I'm part way through re-wiring the garage.

How do I fit a central RCD circuit breaker type thing so that I don't have to plug my ciruit breaker into every drill, welder, etc?

I would like to be able to replace one fuse(old fashioned fuse wire type) in my consumer unit with an RCD type MCB - cant find anyone who does a plug in type.

If you like I'll copy your question to usenets uk.d-i-y

- OK. - I guess the answer will be fit a new consumer unit to the house that incorperates said item. (which would be ideal but is hard in that it creates far more work than I'd like it to)

[s-nilnews-nov04]

Can't do exactly what you want: an RCD needs to be in line with both the live and neutral lines, so it can do its "what goes out must come back" (im)balance detection thing. But easy to do what you generally want: put a suitable standalone RCD at a suitable location. "Suitable standalone" RCD would be like one of these:

with its own Enclosure. "Suitable location" - electrically, in line with the supply to the garage. Physically, either next to the consumer unit in the house, or (better) where the garage supply enters. To avoid the lights all going out when the RCD trips, many of us prefer to put a small subsidiary CU into the garage, which has an RCD or an RCBO (an all-in-one circuit-breaker and RCD) for sockets only, leaving the lights on in the event of a trip on the power circuits.

HTH - Stefek

[BigWallop]

Buy a consumer unit that has RCD protection in its main switch gear.

[Pete C]

Hi,

Look for a 'garage consumer unit'.

cheers, Pete.

[Lurch]

On Wed, 17 Nov 2004 21:52:05 GMT, "BigWallop" strung together this:

Nope, should be split load really, useless idea having an RCD cover absolutely everything.

[BigWallop]

Do you think so? I would have fitted an RCD CU for the convenience of having it cover the whole installation, rather than having to place individual RCD protection to each tool or socket as it was being used.

I did see the other week, an RCD mains switch rated at 50mA rather than the normally bought 30mA, which was nice. :-))

[tarquinlinbin]

I'm just about to rip out a CU that has full RCD protection becuase it nuisance trips once or twice a year,usually when I'm away,so that i come home to a nicely defrosted fridge/freezer,,nope best option is split load or if you cant do that for some reason then a main isolator with mcbs..IMHO joe

[Lurch]

On Fri, 19 Nov 2004 00:04:45 GMT, "BigWallop" strung together this:

Yep.

ITYM inconvenience

You wouldn't do that, you'd provide RCD protection to socket circuits only, and the shower if fitted, generally. If you had whole installation RCD protection a faulty immersion heater would end up in falling down the stairs in the dark and\or lost freezer full of food etc...

Well, there's that way and there's doing it properly. ;-)

[BigWallop]

But the original post starts with the lines:

" I'm part way through re-wiring the garage.

How do I fit a central RCD circuit breaker type thing so that I don't have to plug my ciruit breaker into every drill, welder, etc? "

So I assumed that RCD protection covering the whole installation would be best for this type of system. Maybe I'm wrong. :-))

[Lurch]

On Fri, 19 Nov 2004 23:01:50 GMT, "BigWallop" strung together this:

Ah, assumptions, that'll be the problem. I assumed the OP was after RCD protection for the garage circuit only. Whole installation RCDs can make matters worse in many cases.

[BigWallop]

But, in my first reply to the original post, I answered with the line:

" Buy a consumer unit that has RCD protection in its main switch gear. "

Which was meant to point to the garage having its own CU with an RCD mains switch. I didn't mean buy a whole new CU for the house and wire the garage from it. :-))

[Lurch]

On Sat, 20 Nov 2004 00:14:25 GMT, "BigWallop" strung together this:

Oh, with you now, thought you meant whip out the house CU and install it there. In that case then, good idea! As a slight variation on that theme you could do what someone else mentioned further down and fit an RCD in an enclosure in-line with the garage circuit which would cost less. Or, in the interests of future expansion, fit a split load CU and run one circuit from the RCD side for the garage with a view to rewiring the house and eventually adding all the circuits to it.

[RichardS]

I'd still go with a cheap small split load, though, and wire the lighting from the non-rcd side. Oh, and if there was a freezer in there I'd also put that on it;'s own circuit, possibly using a non-standard socket/plug so there isn't the possiblity of using other portable appliances from it.

The last thing that I would want if the RCD tripped was to be plunged into darkness inches from a spinning-down power tool/machine.

[RichardS]

Hmm, re-reading the OP's post, it is highly possible that the lights are supplied from a separate circuit, quite possibly one of the house's lighting circuits, in which case this is a non-issue (save the freezer comment).

But this is just conjecture, and ought to be taken into consideration.

[Phil Nettleton]

snip :-

unless you are relying on the rcd for personal protection which is why thay are rated at 30mA i suspect it was 500mA

[BigWallop]

No. It was rated at 50mA.