Folks,
I had an issue with an RCD tripping because of damp in an outside socket. Of course this took out half of my power.
I believe its straight forward to swap the MCBs for RCBOs but can I do this myself?
Are there any gotchas?
Dave
If you are asking, then you may not be able to do it correctly. It isnt a 'straight swap'. Is there a spare non-rcd way in your consumer unit? Can you get RCBOs for your CU?
Some thoughts ... What make of CU/MCBs? Have you got plenty of space above the current MCBs? Do you have 1 or 2 RCDs? (if 2 you may need a longer N bar). Currently the neutrals will go to the neutral bar(s), are the wires long enough to reach the RCBO positions?
Everything is British General but they have a new range of RCBOs which may have different dimensions where the bus-bar goes..
Yes, I already have one RCBO for a loft supply. I mess with old computers up there so we split it as these can leak to earth.
I have two, not sure how many positions there are on the N-Bar. Could I link the N-Bars?
This might be the deal breaker...
Dave.
You can always crimp on extensions...
You can. Assuming that they fit, and you have a enough non RCD protected ways spare in the CU to put them in. (you don't want them fed from another RCD since they don't discriminate)
Layout and space mostly. Make sure you take the neutral connections from the RCBOs back to the appropriate neutral bus bar. You may need to extend some wires in the CU to get the circuit neutral wires as far as the RCBO.
Check the RCBO is certified for your particular consumer unit - strictly speaking you're only supposed to use things in accordance with the manufacturer's recommendations. More practically, check the busbar tangs fit properly in the RCBO.
Check the rated torque for the connections and ensure the screws are torqued to the correct amount. A common cause of CU fires is overheating due to insufficiently tightened connections.
Theo
It would be interesting to know how many people use a torque screwdriver for this, how many don't, and how many go back later to re-tighten once the wire and cage have stretched and/or compressed. I don't use one but I do re-tighten after a week or so.
And of the ones who do use a torque screwdriver, how many set the manufacturer's values for the specific terminal.
if you need to ask then I'm not confident you can. The main difference from mcbs is that you need to run that circuit's N through the rcbo. Also some mfrs have >1 type of rcbo, some fit a specific CU some won't.
taking the neutral to the wrong place. Shared neutral circuits can bite you on occasion. And of course faulty circuits/appliances that trip the rcbo.
No!
Solder extra length on, sleeving the oin.
A typical split CU has 2x RCDs & many MCBs. Just replacing one wth a RCBO achieves nothing, hopefully you do understand that.
Possibly, if they all have suitably large holes and if you have suitable cable, but just get a longer bar (assuming the CU just uses plastic spacers to divide the N bar area and that they can be removed to allow a longer bar to be fitted)
As JR has said, they can be extended with suitable crimps (and crimping tool!
Its already on RCDs so there shouldn't be any faulty appliances, appart from faulty outside lights which are currently disconnected.
Been there got the tea shirt. When the board was up-graded from my old Wylex with fuses to a split board with RCD and MCB the two lighting circuits had to go on one MCB. It was the smoke detectors. Install was a total bodge. Swapped from cable link to wireless link and all good.
Dave
I suspect its about the same as for car wheel nuts. All too often I see them tighten them up with an air gun to way over the specified torque, then put a torque spanner on "to check"...
... total pants.
I need to order a tool and crimps...
Dave
It's a good idea to have outside power on a dedicated RCD or RCBO for exactly this reason, also with an indoor isolating switch.
How easy it is to do this will depend on your consumer unit. If it has a space in the right place and if RCBOs are available for it. It sounds like your consumer unit may have 2 RCDs each with half the MCBs on it.
Since about 2000, I always install all RCBOs and no RCDs or MCBs.
Of course, you need to fix the damp socket too, to prevent water ingress and allow condensate egress.
Pretty sue its a new light that I fitted recently. Cheap but probably find its IP rating is fictional.....
Dave
Most crimping tools don't do a safe competent job. A soldering iron or gun otoh has many uses, but also takes practice.
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