Discuss 32a mcb on a 2.5m radial in the Electrical Testing & PAT Testing Forum area at ElectriciansForums.net

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As I said its a 32amp mcb, feeding a fused spur downstream. Connected to a combi boiler, obviously the reason I'm asking as I think its to high, im going to change it to a 20 amp. Cheers.
 
433.1.204 Accessories to BS 1363 may be supplied through a ring final circuit, with or without unfused spurs,
protected by a 30 A or 32 A protective device complying with BS 88 series, BS 3036, BS EN 60898, BS EN 60947-2 or BS EN 61009-1 (RCBO). The circuit shall be wired with copper conductors having line and neutral conductors with a minimum cross-sectional area of 2.5 mm2 except for two-core mineral insulated cables complying with BS EN 60702-1, for which the minimum cross-sectional area is 1.5 mm2. Such circuits are deemed to meet the requirements of Regulation 433.1.1 if the current-carrying capacity (Iz) of the cable is not less than 20 A and if, under the intended conditions of use, the load current in any part of the circuit is unlikely to exceed for long periods the current-carrying capacity (Iz) of the cable.
 
If it is a spur from a ring, even if it is spurred off from the origin, then it is ok
 
As I said its a 32amp mcb, feeding a fused spur downstream. Connected to a combi boiler, obviously the reason I'm asking as I think its to high, im going to change it to a 20 amp. Cheers.
So the overload protection is downstream of the cable. It will prevent an overload.

The 32A device will provide fault protection for the cable.

The arrangement is fine.

But totally pointless. Change it to a 20A if you want. Will need testing and certifying.
 
Even though it's fine I'd agree with downrating the breaker simply to save arguments and reduce confusion in future. It will instantly look suspicious in an inspection as it stands.
 
Only to people who should not be doing inspections.
I'd hope that anyone inspecting would at least investigate and check within 433.1.204.
So in a sense everyone should have some degree of suspicion.
I know that some colleges teach that the appendix diagram is the only permitted RFC arrangement which doesn't help matters.
 
I'd hope that anyone inspecting would at least investigate and check within 433.1.204.
I'd hope that anyone inspecting would not care what a regulation dealing with ring finals says when they were looking at a radial.

I know that some colleges teach that the appendix diagram is the only permitted RFC arrangement which doesn't help matters.
As I said - too many numpties about.
 
I'd hope that anyone inspecting would not care what a regulation dealing with ring finals says when they were looking at a radial.


As I said - too many numpties about.
Lol you got me there, read thread too quickly!
 

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