Mains smoke and heat detectors

[ban-all-sheds]

What are you trying to say BAS? Are only BS1363 accessories allowed on a RFC now? I must have missed that.

This has been discussed quite a few times. Yes - if you want to use the OPD/cable rating exemption in 433.1.204 then the circuit may only serve BS 1363 accessories. If you are happy to use cable with an Iz ≥ 32A for your 32A ring final then you can use it for anything which could go on any 32A circuit.

 

[ban-all-sheds]

Did you not read my words that you have just quoted? It's for that very reason that I was asking about the situation if, instead of what is about to happen (implementation of the existing 421.1.201, as written, with 'non-combustible' etc.) the Amendment had explicitly specified that ferrous metal CUs had to be used for 'large houses'.

I did read it - I thought by "instead" you meant what if 421.1.201 said "Within large houses, consumer units and....", with the rest of it being unchanged, your point being that the term "large house" was meaningless.

 

[ban-all-sheds]

Shall we have another one?

I install a circuit for lighting, and only lighting. But availability is critical, so rather than mess about with emergency lights, I supply an online UPS and power the lights from that. Is it a lighting circuit?

 

[JohnW2]

I did read it - I thought by "instead" you meant what if 421.1.201 said "Within large houses, consumer units and....", with the rest of it being unchanged, your point being that the term "large house" was meaningless.

If I had meant "with the rest of it being unchanged" I would have talked about a requirement for a "non-combustible" CU in "large houses", not a requirement for a "ferrous metal one", wouldn't I?!! I did that so that you couldn't (I thought!) say that it was meaningless already, because of "non-combustible" - but you said it, anyway

Kind Regards, John

 

[PBC_1966]

Can the designer do that?

That was what stillp suggested when asked how one is supposed to tell a lighting circuit from a power circuit:

FWIW I think that it means "A circuit that the designer considered to be a lighting circuit" and "A circuit that the designer considered to be a power circuit".

Have we established that a lighting circuit is one which supplies only lights, and nothing else?

I don't think we've established anything, except perhaps that a circuit which feeds fixed lights and nothing but fixed lights pretty much has to be a lighting circuit by reason of common sense application of the term "lighting circuit."

Anything else - Who knows?

 

[stillp]

Gosh, you guys must get worried when labelling the MCBs in a CU!

 

[stillp]

Yes - if you want to use the OPD/cable rating exemption in 433.1.204 then the circuit may only serve BS 1363 accessories.

Really? No FCUs then?
Sorry, I only have the BGB. What'd the difference between that subclause and the earlier one?

 

[JohnW2]

Yes - if you want to use the OPD/cable rating exemption in 433.1.204 then the circuit may only serve BS 1363 accessories.

Really? No FCUs then? Sorry, I only have the BGB. What'd the difference between that subclause and the earlier one?

All the FCUs I've seen have got "BS1363" embossed on them - is that wrong?

I don't think the relevant wording has changed, materially if at all, since BRB/BGB (and quite probably earlier). Read literally, it seems to say that the 'cable CSA dispensation' only applies if the circuit is supplying BS1363 accessories. There are sometimes arguments about the 'acceptability' of having 20A DP switches in a spur from a ring final, but I've never heard it suggested that FCUs are not acceptable.

Kind Regards, John

 

[stillp]

Aaagh! Sorry, I was thinking of 20A switches.

 

[ban-all-sheds]

Gosh, you guys must get worried when labelling the MCBs in a CU!

Never heard of anybody worrying if "Upstairs lights" needs to say something different if there's also a fan and a shaver socket in the bathroom.

 

[EFLImpudence]

That's a good point and likely the cause of all the confusion, along with the ignorance of the author of Table 52.3.

A label on a CU stating "Lights" or "Upstairs Lights" or "Downstairs Lights" does not actually make it a "lighting" circuit.
It is just a (normally) 6A circuit to which anything suitable may be connected.

The same for "Cooker" - just a (normally) 32A circuit to which, with spare capacity, a socket or anything else may be connected.

So - no such thing as a "lighting" circuit; just power circuits supplying anything you want. The label merely stating what is supplied and not the definition of the circuit.

 

[JohnW2]

So - no such thing as a "lighting" circuit; just power circuits supplying anything you want. The label merely stating what is supplied and not the definition of the circuit.

Indeed - and, as most people have been saying, even if there were adequate definitions of the two types of circuit, why should the minimum CSA be different for the two?

Kind Regards, John

 

[PBC_1966]

So - no such thing as a "lighting" circuit; just power circuits supplying anything you want. The label merely stating what is supplied and not the definition of the circuit

Also, I may have labeled a fuseway or MCB "Lights" many times over the years, since that is the primary purpose of the circuit (not meaning that it can't also supply the odd fan or other device).

I have never labeled an MCB as just "Power." To do so would be of absolutely no help in identifying the devices fed by that MCB, since every MCB is supplying power, including the one(s) labeled "Lights."

 

[PBC_1966]

Speaking of labeling fuses or MCB's, I do wish that in domestic settings people wouldn't label fuses/MCB's with things like "Susan's bedroom" and would use something like "Rear bedroom" or "Southwest bedroom" instead.

 

[stillp]

Gosh, you guys must get worried when labelling the MCBs in a CU!

Never heard of anybody worrying if "Upstairs lights" needs to say something different if there's also a fan and a shaver socket in the bathroom.

Exactly!