Consumer Unit Full - Fitting an RCD or RCBO

[pbar]

I've had an extension built which includes several new sockets. These sockets have been put on a new MCB in the consumer unit, it's the grey MCB in the pictures. As you can see it's not on the RCD side of the CU. I know there's certain criteria as to whether sockets should be on the RCD side (whether the sockets might be used for outside appliances, etc.) but for safety I'd rather have every socket in the house protected by an RCD, as they were before the extension was built. So, as the CU is full, I guess I have 3 choices. Install a new CU, fit a separate standalone RCD above the CU, or exchange the new grey MCB for an RCBO, this is my preferred option I think, just wondering if this is standard practice, and if it contravenes any regulations. That's if they are available for this CU which is a Memera 2000, which is my second question, is anyone aware of where I can get hold of an RCBO for this CU. Thanks!

 

[jj4091]

Why can't you fit a new bus-bar & move the mcb over?

 

[JohnD]

Hahahahahahahahahaha!

Of course!

MEM RCBOs are readily available.

The RCBO gives an additional advantage that a fault on one circuit will not cause power to be lost on other circuits, as will happen when you have a split-load with several circuits protected by a single RCD.

As you want a B32 with 30mA they might not be available locally ex stock, but they can be assembled by fitting a clip-on RCD Pod onto a a B32 MCB. (this is a correct way of doing it, they are manufactured as snap-together parts so you can make practically any rating you happen to want).

You can do this with any current model of Memera 2000 or Memshield 2 MCB, except for the budget "Memera 2000 AD" ones whose part no begins with AD.

The ones you can fit them to look like your grey Eaton MCB with the little red/green window. The same company makes them with different brand names; Memshield 2; Memera 2000, Eaton, Bill Talisman.

So you can fit a Pod onto your new MCB. It might be more convenient to buy another one, though,so you can assemble it on the kitchen table and have it ready before starting work.

The part no of the RCBO is ALB321H30
the part no of the Pod is AH30

You can get them at any Electrical wholesaler (except the ones that only sell low-quality,low price stuff) but not usually at DIY sheds. Any place that supplies Industrial Electricians will have them as they are very popular there. However an Industrial supplier will mostly keep "C" type MCBs which are slower reacting, you want a "B" type. He will either have it in stock, or order for next day.

 

[JohnD]

p.s. if you put your email address in your profile, someone might offer you one.

 

[pbar]

p.s. if you put your email address in your profile, someone might offer you one.

Hi, thanks for your very informative and helpful reply, most places seem to sell the two items together, already assembled.
I've just updated my profile to show my e-mail address. Let me know if it doesn't show!

 

[LondonRay]

Just so you you know,. your e-mail does show.

Hope you get what you want

 

[pbar]

Thanks guys.
And thanks for the offer John, appreciate it but was able to get a new one off Ebay.
Just hope I can get the old one out easy enough, from what I remember these things are awfully tight.

 

[pbar]

Fitted the RCBO in place of the MCB, thanks for advice, all went well, not much room in there though, but squeezed it in.
Just one thing, I've noticed on the consumer unit, it says 100 amp max. I have in there 3 x 32 amp for the circuits and 3 x 6 amp for lights. Is the limit exceeded now then, or is it deemed as ok as obviously everything won't be on and running to the max at the same time, and is this still legal and safe?

 

[davy_owen_88]

I've noticed on the consumer unit, it says 100 amp max. I have in there 3 x 32 amp for the circuits and 3 x 6 amp for lights. Is the limit exceeded now then, or is it deemed as ok as obviously everything won't be on and running to the max at the same time, and is this still legal and safe?

Exactly. The actual word for it is diversity. No problems there unless the diversified load is well over the limit.

On a side note, I don't know why you didn't just go with jj4091's advice. I'm sure it would have been quicker and cheaper. Oh well

 

[pbar]

Hi, thanks for your reply, sets my mind at rest.
I didn't go through the busbar route as I haven't had any experience previously in that area and I had an electrician look at it once who said he wasn't sure if that can be done in a Mem 2000 unit, so I went for the RCBO option as it seems straightforward and....well, I like em. They're sexy!
Just one thing - what would happen if (unlikely, I know) everything was on at the same time and the 100 amp was excceded.
Thanx.

 

[davy_owen_88]

so I went for the RCBO option as it seems straightforward and....well, I like em. They're sexy!

I think you and JohnD would make a lovely couple

Anyway, if you were to exceed the 100A rating for a significant amount of time then the main fuse will blow. In the time taken for that to occur the main switch may well overheat and melt. Fortunately, when the main switch does melt it should blow the fuse pretty quickly If the overload is short then it is unlikely to do any damage atall.

 

[pbar]

I think you and JohnD would make a lovely couple

lol

Thanx for your advice

 

[bobdabuilda]

Why can't you fit a new bus-bar & move the mcb over?

Can anyone tell me where I can buy a new MEM A100HE 100A 30mA RCD to fit in a MEM 2000 CU please? Googled it and got sweet FA apart from a few 'used' ones on ebay! Was worried whether they'd be safe to be honest hence the new route.

Also would retrofitting RCDpods onto the lighting mcbs make the whole setup compliant with the latest regs? Would they fit without having to cut bigger holes in the cu?

 

[JohnD]

p.s. if you put your email address in your profile, someone might offer you one.

 

[bobdabuilda]

p.s. if you put your email address in your profile, someone might offer you one.

thanks John. Do you know if the MEM eaton mr30 rcd pods will retrofit onto the mem mcbs from a mem 2000 cu?