Plastic switch in external meter box

No. I stand by FUSED SWITCH [ or switch fuse] like a KMF, not being like a DB. There is one neutral connection in, and one neutral connection out. Same for the earth conductor. There is no option for other neutrals or CPCs unless you are particularly rough. You left out a fundamental part of the BS7671 definition of what is a DB. "......together with terminals for the neutral and circuit protective conductors" Consumer Units and the Distribution Boards that are similar switchgear to Consumer Units have neutral and CPC bars. The genuine old style one way distribution boards like wylex/ MEM had a rewirable or HRC fuse or plug in retro MCB, but also had an earth bar and a neutral bar.

I'm afraid I'm not following that thinking at all - a swicthfuse does have terminals for the outgoing circuit - that's where you connect the outgoing cable to. There's no need for each terminal to accommodate more than one conductor since it's only a 1-way device. There's no requirement for them to be multi-way bars - just terminals.

Perhaps the point was not clear. Consumer Units are a particular DB for use in Domestics. A KMF has a HRC fuse that is not that consumer friendly to remove unless you are familiar with them. There is no indication that they have blown; same for BS3036, but of course, you can pull this rewireable out and see if the wire is healthy or not.

So the traditional CU fitted with 5A to 30A BS 1361 ("Specification for cartridge fuses for a.c. circuits in domestic and similar premises") HBC fuses isn't a consumer unit????

Even when the KMF is used as an isolator, that does not qualify it as a DB.

No but it might suggest that it should be suitable for operation by ordinary persons - and equipment that doesn't meet BS EN 61439-3 might not be (which is where 421.1.201 starts off).


  - Andy.

No. I stand by FUSED SWITCH [ or switch fuse] like a KMF, not being like a DB. There is one neutral connection in, and one neutral connection out. Same for the earth conductor. There is no option for other neutrals or CPCs unless you are particularly rough. You left out a fundamental part of the BS7671 definition of what is a DB. "......together with terminals for the neutral and circuit protective conductors" Consumer Units and the Distribution Boards that are similar switchgear to Consumer Units have neutral and CPC bars. The genuine old style one way distribution boards like wylex/ MEM had a rewirable or HRC fuse or plug in retro MCB, but also had an earth bar and a neutral bar.

I'm afraid I'm not following that thinking at all - a swicthfuse does have terminals for the outgoing circuit - that's where you connect the outgoing cable to. There's no need for each terminal to accommodate more than one conductor since it's only a 1-way device. There's no requirement for them to be multi-way bars - just terminals.

Perhaps the point was not clear. Consumer Units are a particular DB for use in Domestics. A KMF has a HRC fuse that is not that consumer friendly to remove unless you are familiar with them. There is no indication that they have blown; same for BS3036, but of course, you can pull this rewireable out and see if the wire is healthy or not.

So the traditional CU fitted with 5A to 30A BS 1361 ("Specification for cartridge fuses for a.c. circuits in domestic and similar premises") HBC fuses isn't a consumer unit????

Even when the KMF is used as an isolator, that does not qualify it as a DB.

No but it might suggest that it should be suitable for operation by ordinary persons - and equipment that doesn't meet BS EN 61439-3 might not be (which is where 421.1.201 starts off).


  - Andy.