RCBO consumer unit

iep

Joined
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United Kingdom
Hi,
Looking to have my old wire fuse CU with a new full RCBO one. Currently have 11 circuits in the house so guess a 12 or 14 way box would do the job. I considered a split load box but the way the various circuits in our house are organised, there is no 'ideal' way to split the load between the two RCDs. So, decided to bite the bullet and go for a full RCBO box.

Problem is that, while there are loads of split load boxes to choose between, there don't seem to be so many single load boxes for full RCBO domestic installations.

I've seen a couple of MK Sentry ones and a couple of Wylex ones but don't really know if either are any good. What are people's thoughts on the MK sentry boxes. They seem to be a bit too cheap to be any good?

FYI, I won't be doing the install myself. I have a guy lined up to do the work (as soon as he comes back from his 1 month holiday in Australia. Clearly I am in the wrong line of work).

Cheers,

iep
 
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Before you or the guy, on holiday in Austrailia, can determine what is the right size replacement CU, he will need to run a full PIR on your installation to establish that your wiring meets the test criteria.
So I would wait for him to come back home before doing anything.
 
I had the wiring checked out by a different electrician about a year ago.

The guy then said that all was in order and that it was up to me whether I wanted to replace the old wired fuse unit but that the wiring would be compatible with a new RCD CU if I wanted to do that. As a result we decided to delay the work while we sorted out more urgent stuff on the house.

Unfortunately, that guy has since retired (hence I'm using someone else) but I'm guessing his original assessment still stands.

Any advice on recommended CUs gratefully received.

iep
 
Just found a cu made by TD-Line that comes complete with a full set of RCBOs. Anyone used TD Line stuff before? Any issues with it?

Cheers,

iep
 
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I had the wiring checked out by a different electrician about a year ago.

The guy then said that all was in order and that it was up to me whether I wanted to replace the old wired fuse unit but that the wiring would be compatible with a new RCD CU if I wanted to do that. As a result we decided to delay the work while we sorted out more urgent stuff on the house.
That's good - as long as you still have the Periodic Inspection Report and test results he gave you then the new electrician shouldn't have too much of a problem with that - though in my case I would always insist on conducting another PIR because I would be taking responsibility for the installation.


Any advice on recommended CUs gratefully received.

iep
The problem with what you propose as opposed to what the electrician might propose is that most of the new standard boards are designed to take mcb's with split load RCD's and not a rack of RCBO's.
I am in the process of fitting a new install with a 10 way board with 8 RCBO's now and even with new cable runs into the CU Its already getting quite full in there. When trying to install a new RCBO filled board with old pre cut wiring it is much more difficult.
 
As regards the old precut wiring, the existing wiring runs down from the ceiling in the garage to the existing CU which is about 1 foot off the floor. The previous electrician said he would move the CU further up the wall so that he had plenty of slack in the existing wiring to work with.

Appreciate your concerns about space in the box though, that's why I'm asking if any brands are better than others for this type of install.

FYI, the new electrician knows the retired one so (I'm hoping) he is happy to go on his PIR.

As mentioned in previous post, found a TD-Line box that seems spacious enough complete with RCBOs. Just don't know if they are any good.

I'd be happy to fork out for an MK one but, TBH, I had a look at one in B&Q and it seemed just as cheap and nasty as the budget ones.

ip
 
Let your electrician choose the CU - he will be the one installing it, and providing a warranty for it, so you have to let him choose the one that he's comfortable with.

While he's away you can be thinking about what circuits you have, and what you'd like to have (maybe not now, but in the future), and have a CU large enough for future growth.

The items on the list below won't all apply to you, but they are worth thinking about:

  • Upstairs sockets
  • Downstairs sockets
  • Kitchen sockets
  • Circuit for appliances
  • Cooker circuit
  • Non-RCD circuit for F/F
  • Non-RCD circuit for CH boiler
  • Dedicated circuit for hifi
  • Dedicated circuit for IT equipment
  • Upstairs lights
  • Downstairs lights
  • Lighting circuits with switches in the usual places but with 2A/5A round pin sockets at low level.
  • Immersion heater
  • Loft lights
  • Shower
  • Bathroom circuit
  • Alarms
  • Supply for outside lights
  • Supply for garden electrics
  • Supply for shed/garage
You don't have to have RCBOs throughout, you could have a CU with at least 3 sections, 2 on RCDs and one not into which you can install a mix of RCBOs and MCBs.

If you live somewhere where supplies are dodgy in the winter, have the lights, the boiler supply, and a socket in each room wired to a separate CU, or a separate section in a large one, that can be supplied by an emergency generator - lights, heating, TV and a kettle/microwave make life a lot more bearable, so it might be an idea to have a CU capable of allowing that, after a bit of rewiring.


but the way the various circuits in our house are organised, there is no 'ideal' way to split the load between the two RCDs.
Can't really imagine that.

11 circuits are 11 circuits - 5 on one RCD, 6 on the other, or whatever.

What would you "ideally" do which you can't, and why can't you?
 
Ban-All-Sheds. Nice post, thanks. Like the idea of a circuit into which you can wire a generator. I might mention that to the electrician.

Probably fair comment on the brand of CU. I'm sure my new electrician has a preferred brand he'll want to use. Just can't get hold of him right now and thought I'd shop around for a bargain while he was away.

You're quite also right, I'm sure there would be a way to use a simple split load box but I'm a bit belt and braces and prefer the idea of separate protection on each circuit. I don't see any downside on a full RCBO box (aside from the cost) but perhaps I'm missing something?

iep
 
Tell you what, why don't a phrase this differently. Is there a brand of CU that is considered 'rolls royce' and so any electrician would be happy to fit?

I used to think that MK was top dog but, as I said, the units I looked at in B&Q didn't seem particularly nicely made. Maybe the rcbos themselves are where I'd see the difference?

Cheers,

iep
 
There are several different brands of CU. Some are budget ones, some are more expensive.

I have three makes that I use. I carry spares so its only a walk to the van if I need an extra bit.

As stated before, Many CUs just don't have enough space (or its a PITA) for an all-RCBO configuration. Personally I would use Hager or MEM. I never did hear of TD Line and would refuse to install anything like that.
I would want a make that has been around for a long time. Then you'll be able to get an additional breaker in 10 years time, if you need one.

Any decent electrician will get kit at trade prices, even with a modest markup the price will still be cheaper than you can get stuff at the sheds.

Don't do it. If you buy off your own bat it will probably be wrong. The sparky will then blame you if anything goes wrong.
 
Tell you what, why don't a phrase this differently. Is there a brand of CU that is considered 'rolls royce' and so any electrician would be happy to fit?

Merlin Gerin (make sure you are sitting down when you find out how much all those MG rcbos are going to cost - also B types seem somewhat rare)

So while it is the 'rolls royce' not really ideal putting in a simple domestic

I like Hager, but thats not to say the guy who is fitting it will
 
Thanks guys, looks like my best plan is to speak to my spark first.

Cheers,

iep
 
I'm sure there would be a way to use a simple split load box but I'm a bit belt and braces and prefer the idea of separate protection on each circuit.
Fair enough, but that wasn't what you said about the problem with splitting them over 2 RCDs.


I don't see any downside on a full RCBO box (aside from the cost)
Size.

Some are tall, and need a lot of vertical space, some are more than 1 module wide and need a lot of horizontal space.
 
Thanks ban. I guess another question then might be who makes the 'tallest' CUs? Noted from another thread that Wylex metal clad are quite tall?:

//www.diynot.com/forums/viewtopic.php?t=180570&start=0

Pretty sure ours is a TNCS installation so could probably go with one of these plus a 100A switch and however many RCBOs are required (or possibly 2 11 way ones to give even more space and some room for further expansion in the future).

http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Ns_1/index.html

I'll be checking with my electrician as advised but am just keen to understand the decisions he'll be making.

Cheers,

iep
 

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