Discuss Table Saw trips RCBO in the UK Electrical Forum area at ElectriciansForums.net
The 20amp was first used as it was spare and we did not need any heavy loads so it would have been fine. The correct fuse rating for the ring would have been a 32amp RCBO. So fitting one would be OK as it is a true Final Ring cct. However I like the idea of the C curve as I had forgotten about that characteristic.I would not be putting a 32a rcbo just because its been suggested by someone I don't know on an Internet site.
A 32a rcbo may be fine or it may be dangerous. You wouldn't know without further tests. I always think there must be a reason why someone has chosen to put a 20a on what seems to be a ring.
The 20a type C suggestion is good, assuming you can get an EFLI result low enough.
Working on the principle that the information the OP has given us is correct then a 32a would be a good solution.I would not be putting a 32a rcbo just because its been suggested by someone I don't know on an Internet site.
A 32a rcbo may be fine or it may be dangerous. You wouldn't know without further tests. I always think there must be a reason why someone has chosen to put a 20a on what seems to be a ring.
The 20a type C suggestion is good, assuming you can get an EFLI result low enough.
OP replied before I posted mine. >.<Working on the principle that the information the OP has given us is correct then a 32a would be a good solution.
They said that it is a ring and the 20a was installed at the time as that was what they had to hand.
If the installation paperwork verifies this then I see no issue.
My personal advice would be to get a local sparky to do the swap so they can carry out required tests etc. and ensure the correct part is installed.
Obviously there is no such thing as a 10 minute job but this is pretty close.
The same could be said about not changing it.I would not be putting a 32a rcbo just because its been suggested by someone I don't know on an Internet site
Can you explain how it could be dangerous ?A 32a rcbo may be fine or it may be dangerous.
Yes because as already said they didn't have a 32.There must be a reason why someone has chosen to put a 20a on what seems to be a ring.
How can putting an underrated 20amp rcbo on a circuit that requires around 5kw be a good suggestion.The 20a type C suggestion is good, assuming you can get an EFLI result low enough.
All the work was carried out by an electrician and certified. FYI THE DISTRIBUTION IS from a Henley block off the main CSU fed into and additional CSU for distribution. A 62amp breaker is fitted in that CSU which then has the 40amp MCB feeding the cabin.It's been an interesting thread. It's slowly emerged that there seems to be a well engineered distribution circuit and the fact it was a "ring" got slightly overlooked at first as the very logical reaction was 'that's more than 20 amps so of course it will trip'.
Those commenting at the beginning didn't know there was a 10 sq mm SWA feeding it and it initially sounded like a cheap and nasty job.
To my thinking there are two definite things to check before changing that device:
-Is the Zs low enough for a B32? If not it would rely on RCD technology to turn off in time under fault conditions, and a new certificate needs to state that RCDs are being employed for fault protection. (If moving to a type C then even more reason to check this).
-Do end-to-end tests confirm it's a healthy ring final circuit and is eligible to be protected by a 32 amp device in the first place?
I'd also want to know the OCPD of the distribution circuit, it might be 25 amp MCB for all we know and the problem just moves. Unlikely, but possible!
It comes down to a simple choice
-stick a B32 in and hope all is ok
-get 5 minutes of testing done and be sure all is ok.
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