Upgrade old MCB to RCBO

[Joyrider]

Hello all
My CU is 18 years old and is doing the job fine. It's the older plastic enclosure box. RCD protects only half the MCB such as ring sockets, shower and kitchen shockets.
Its a fairly small box. 1 of the unmarked is garden brick shed and other I will need to check again. The B6 "Stor" is a single light under the stairs where the CU is installed.
The kitchen is extended building and the cooker is plugged into a kitchen ring socket, not its on MCB. I have seen cooker normally have thier own MCB so not sure what happended here. It was the same sparky that rewired the whole house when I had the house walls gutted.

RCBO were quite expensive intially but has come down in price now so is it possible to fit some RCBO to give a partial upgrade without complications.

1. Is it wise to replace the 3x 32Amp MCB with miniture type A RCBO and rest on RCD??
2. Does it need to be notified to local building regs?


Apreciate any feedback...even if they are harsh truth

 

[sparkwright]

I tried replacing a few old Lewden breakers in a board of a similar vintage.

I was trying to save money.

The new RCBOs didn't quite fit the busbar, and I was running out of room near the top.

Stressful.

Until I pulled the whole lot out, and rushed to Screwfix (Saturday) and bought a whole new metal Lewdwn consumer unit with new RCBOs.

 

[Joyrider]

I tried replacing a few old Lewden breakers in a board of a similar vintage.

I was trying to save money.

The new RCBOs didn't quite fit the busbar, and I was running out of room near the top.

Stressful.

Until I pulled the whole lot out, and rushed to Screwfix (Saturday) and bought a whole new metal Lewdwn consumer unit with new RCBOs.

Oh FFS...so I can't just swap with same brand RCBO??
May I ask did you try same brand RCBO or different

The mini RCBO with just blue cable seems like the same height as the standard MCB.

 

[sparkwright]

You can try.

Yes it was the same brand, but it didn't fit at all well.

It was Lewden, same as yours - though I think there may be another name for yours - can't quite remember now.

I suppose you could try getting older ones from E-bay...

Yes, there are mini ones available, sometimes.

 

[sparkwright]

Then again, you're not going to get old style A type ones on E-bay...

 

[Joyrider]

You can try.

Yes it was the same brand, but it didn't fit at all well.

It was Lewden, same as yours - though I think there may be another name for yours - can't quite remember now.

I suppose you could try getting older ones from E-bay...

Yes, there are mini ones available, sometimes.

I believe mine is old version knows as "Lewden Control Gear"
So looking at some pictures of my MCB and the mini RCBO on google pictures...I see what you mean about the busbar, the position busbar is different so they dont line up properly.

So if I get all RCBO then no drama with the busbar??

 

[flameport]

Oh FFS...so I can't just swap with same brand RCBO??

Theoretically you can.
In reality, new parts may not fit older consumer units even if they are the same brand.

If you want CGD RCBOs, then they can be obtained here: https://www.denmans.co.uk/den/root-...c/DEDI_1_3?page=1&filter=manufacturerName:CGD

However a more sensible option would be to replace the whole thing, as having a single RCD for all of the high load circuits is a poor choice, and it's a Type AC which would not be permitted on any additions or new circuits.

 

[sparkwright]

Theoretically you can.
In reality, new parts may not fit older consumer units even if they are the same brand.

If you want CGD RCBOs, then they can be obtained here: https://www.denmans.co.uk/den/root-category/Power-Distribution-&-Circuit-Protection/Consumer-Units-&-Devices/RCBOs/c/DEDI_1_3?page=1&filter=manufacturerName:CGD

However a more sensible option would be to replace the whole thing, as having a single RCD for all of the high load circuits is a poor choice, and it's a Type AC which would not be permitted on any additions or new circuits.

As Flameport says, ditch all that old junk.

 

[Joyrider]

Thank you both for the suggestion to ditch the junk. I am considering that a last option and bring new tails from bottom entry . At the moment the tails are cliped to the wood.. Its an eyesore yes but its under the stairs out of sight

My main issue is space. The CU is fitted under the stairs in tight space. The current CU is about 320mm wide and 220mm high and the new metal 10ways are 250mm to 260mm high .
The bottom right corner is touching the mains water piple so can't shift to right anymore. The top left corner has about 50mm gap before it touches a step... and this would involve trimming some wood to shift the CU left. I suppose that would also allow the CU to drop maybe 30mm at most.

God knows why the sparky did not fit the CU a bit more to the left but guessing at that time this was standard size for 10way CU

Other option is to fit a smaller 7 way unit full of RCBO.

 

[Joyrider]

Theoretically you can.
In reality, new parts may not fit older consumer units even if they are the same brand.

If you want CGD RCBOs, then they can be obtained here: https://www.denmans.co.uk/den/root-category/Power-Distribution-&-Circuit-Protection/Consumer-Units-&-Devices/RCBOs/c/DEDI_1_3?page=1&filter=manufacturerName:CGD

However a more sensible option would be to replace the whole thing, as having a single RCD for all of the high load circuits is a poor choice, and it's a Type AC which would not be permitted on any additions or new circuits.

Just noticed those are type AC so not really much of upgrade.. would ideally like type A.
This has has been educational so won't bother go down that route

 

[Harry Bloomfield]

My main issue is space. The CU is fitted under the stairs in tight space. The current CU is about 320mm wide and 220mm high and the new metal 10ways are 250mm to 260mm high .

I faced a similar issue, a while ago, wanting to swap a CU with no RCD protection, to one with two RCD's, plus many more MCD's, and so a much wider CU. I was also keen to avoid as many joints as I could, but also to only have them within the CU, if at all possible. All of the circuits came down, from above, except the supply tails, which entered from the back, through the wall.

The only way the CU would sensibly fit the space, was to mount it close to the ceiling, following the 45 degree slope of the ceiling. The slope like yours - bottom of stair, to the left. It looks a little odd, but it worked out to be a practical solution.

 

[Why Not Indeed]

Seems "obvious" to me that you've got space to the left and above. My guess is that board the CU is on was installed before the plasterboard with the wallpaper on. Take enough of the plasteboard off to give yourself some more room. Like you say it's under the stairs, so you don't have to do a great job of making good afterwards.

 

[thomp1983]

If you've an outside stop tap then I'd reroute the mains water pipe so you can install something fit for purpose with a sensible layout.

 

[Joyrider]

Seems "obvious" to me that you've got space to the left and above. My guess is that board the CU is on was installed before the plasterboard with the wallpaper on.

Thats correct, underside of the stairs was not a pretty sight so the builder just fitted that flywood. There is not much room before it touches a step. I can maybe cut away some wood and free up anouther 30mm to the left.

 

[Joyrider]

So after some google search I found 2 options for 10 way CU that will fit with minimum adjustment. Both these boxes can be picked up for under £45 with just the 100A switch.

BG CFUSW10-01 316mm x 230mm

Hager VML110 297mm x 245mm

I get the impression Hager is a highend brand and don't see many of their RCBO for sale on ebay. I have seen a good deal for 8x new boxed Crabtree Starbreaker on ebay. 7x of them direct match of the ratings..but a 50A missing.

So can I use all Crabtree RCBO on a different brand board or is that a stupid idea???