Swapping out RCDs and MCBs for RCBOs
- Thread starter Nakajo
- Start date
It all very much depends on the existing wiring and the type and layout of the existing consumer unit. Some of the older ones were not made with RCBOs in mind.
Take a photo of the innerds of the consumer unit (Turn the power off at the main switch & remove the cover first!) and someone can give you a view.
Take a photo of the innerds of the consumer unit (Turn the power off at the main switch & remove the cover first!) and someone can give you a view.
Really? Who's spec is that? What is actualy wrong with it, the way it is?
I would like to help and advise but Would still like to see a pic of the type and layout of the CU. There are dependencies as some of the internals of the board need to change to support all-RCBO layout.
In any event whoever is doing the job would need to rip out all of the existing leaving just the main switch, if its a split load CU (ie two RCDs with their own MCB groups) then you'd need a single busbar, and continuous terminations for earth and neutral.
If the CU is a flexible type then it's not too hard to do.
I would like to help and advise but Would still like to see a pic of the type and layout of the CU. There are dependencies as some of the internals of the board need to change to support all-RCBO layout.
In any event whoever is doing the job would need to rip out all of the existing leaving just the main switch, if its a split load CU (ie two RCDs with their own MCB groups) then you'd need a single busbar, and continuous terminations for earth and neutral.
If the CU is a flexible type then it's not too hard to do.
It's the spec. that the client issued to the contractor on which to base his tender.
As it stands, whenever a circuit trips, all the circuits trip, which is annoying and makes pinning down a problem harder to identify.
I only have a photo of the board with the cover on - I don't think it'll help much. I guess the all the work required is local, so probably not too difficult.
As it stands, whenever a circuit trips, all the circuits trip, which is annoying and makes pinning down a problem harder to identify.
I only have a photo of the board with the cover on - I don't think it'll help much. I guess the all the work required is local, so probably not too difficult.
Attachments
The Wylex unit that is pictured does meet the requirements of BS7671. It has been installed with two RCDs with a number of MCBs on each RCD. With this design, the problem (as you know) is that a fault on one sub-circuit takes out half of the installation. As above, this arrangement does meet the requirements of the regs.
If thje specification was for an all-RCBO board then there will be space in there for an all-RCBO arrangement. You'll need an RCBO for each of the "ways", also you'll need a new full-width busbar, the existing one will have been chopped up into (at least) two pieces.
If thje specification was for an all-RCBO board then there will be space in there for an all-RCBO arrangement. You'll need an RCBO for each of the "ways", also you'll need a new full-width busbar, the existing one will have been chopped up into (at least) two pieces.
An awful lot of circuits for a terrace house. I guess it has been rewired?
A recent wylex that. (having NSX)
A recent wylex that. (having NSX)
On right-hand RCD:
1. 32A Hob
2. 32A Ground ring
3. 32A Loft ring
4. 16A D/<Something> M-way socket ?
5. 16A. Pump / Immersion ?
6. 6A <Something> lights
7. 6A 1st floor lights
8. 6A Loft lights
On left-hand RCD:
1. 32A 1st floor ring
2. 32A Kitchen ring
3. 20A Boiler
4. 20A Alarm
5. 6A Utility & ground lights
6. 6A Smoke alarms
7. 6A Basement lights
And one not-matching old style. Doesn't that look lovely?
Loft RFC sounds a bit OTT to me!
20A for boiler and alarm ?
Arh so it has a basement and loft. Starts to explain things. And wired to modern standards
Loft ring and loft lights shouldn't be on the same RCD IMO.
Arh so it has a basement and loft. Starts to explain things. And wired to modern standards
Loft ring and loft lights shouldn't be on the same RCD IMO.
Protecting the cable, not the appliance. It's gonna be in 2.5mm² so no worries
. I don't have a problem with putting them on a 6/10/16/20A.There's almost always going to be an FCU in-line somewhere anyway.
And no, loft lights & sockets should be split over two RCDs
It's anyway nice for the MCB's to do the work rather than the fuse.
And 2.5mm for an alarm is OTT.
And 2.5mm for an alarm is OTT.
To elaborate on this, the two RCDs would need to be removed, and the two neural bars will need linking - a link should be available.
Does this work definitely need to be carried out?
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