Wiring modular switche

[ban-all-sheds]

But we all know we cannot connect DP switches <32A that are not to BS1363 to a 32A circuit...

No, not all of us.

Some of us do not know that at all.

 

[RF Lighting]

But we all know we cannot connect DP switches <32A that are not to BS1363 to a 32A circuit... [Dive for cover...]

There is certainly nothing in the regs that says that only BS1363 accessories can be connected to a ring final (if that's what we are talking about) - and the 'current rating' of a switch presumably relates to the current passing through the switch (in the OP's case limited by a 13A downstream fuse), regardless of the OPD (32A or otherwise) of the circuit feeding it.

Kind Regards, John

433.1.5

 

[Taylortwocities]

Hi RF. Very wishy washy.

Care to guess what the definition of "long period" is in 433.1.5? If the circuit through this switch is to power an oven, is "long period" enough to cook the Sunday roast? Or is "long period" just enough time to warm up a pitta bread?

 

[JohnW2]

There is certainly nothing in the regs that says that only BS1363 accessories can be connected to a ring final (if that's what we are talking about) - and the 'current rating' of a switch presumably relates to the current passing through the switch (in the OP's case limited by a 13A downstream fuse), regardless of the OPD (32A or otherwise) of the circuit feeding it.

433.1.5

Goodness - are you still using the BRB?! I take it that you refer to what became 433.1.103 in the BGB and is now 433.1.204 in the current BYB? If so, as I said, it appears to say nothing about ring finals being allowed to supply only BS1363 accessories - or do you disagree?

Kind Regards, John

 

[JohnW2]

Hi RF. Very wishy washy. Care to guess what the definition of "long period" is in 433.1.5? If the circuit through this switch is to power an oven, is "long period" enough to cook the Sunday roast? Or is "long period" just enough time to warm up a pitta bread?

[you still using the BRB, too? ] Agreed - but, in any event, that's only to do with the topology of the circuit etc. (i.e. not installing lots of sockets, or originating lots of spurs, at points close to one end of the ring) - it's got nothing to do with the acceptability of connecting a 16A (or 20A) (non-BS1363) switch to a ring, has it?

Kind Regards, John

 

[ban-all-sheds]

Care to guess what the definition of "long period" is in 433.1.5? If the circuit through this switch is to power an oven, is "long period" enough to cook the Sunday roast? Or is "long period" just enough time to warm up a pitta bread?

Dunno.

But it might be worth noting that were it a 20A radial, with no 16A accessory concerns, the regulations would unconditionally (apart from "domestic environment") allow a 10kW oven to be supplied by it....

 

[ban-all-sheds]

it appears to say nothing about ring finals being allowed to supply only BS1363 accessories - or do you disagree?

I do, because it is an exemption from all the other regulations regarding Ib vs In vs Iz etc.

If you don't want to comply with all of the other regulations relevant to that, the only valid exemption you have is for BS1363 accessories supplied by a ring final etc. 433.1.204 doesn't have to say "only"¹ because it is describing what is allowed to be exempted from all the other regulations - if it's not on the list, it's not coming in, basically.

I am sanguine about using 20A rated switches, because 20A is the most that's allowed to be carried by the cable. I have a much harder time with 16A ones.


¹ And thank god it doesn't, for if it did I can assure you that there would be hard-of-reading people who would argue that BS 1363 accessories could only be supplied by a RF....

 

[milbo1990]

2. the DP (double pole) switch will have 4 terminals. 2 for the supply in, and 2 for the load out connection (to the socket in your case).
Here's a description Double Pole Switches & Cooker Control Units - MK Electric

So you would have somewhere to connect your neutral connections.

Well therein lies the problem! A call to RPP confirms that I've been handed single pole switches. Guess I'll be going back to CEF for a third time them tomorrow!!

 

[EFLImpudence]

Sorry to resurrect this - having now spoken with the manufacturer direct - 16a DP switches are what I need. These have the terminals 'live 1' and 'com' and the manufacturer reassures me that they're normally used for what I want.

Why would a DP switch have a terminal marked 'COM' and what would you put in it?


Edit - Too late,

 

[JohnW2]

it appears to say nothing about ring finals being allowed to supply only BS1363 accessories - or do you disagree?

I do, because it is an exemption from all the other regulations regarding Ib vs In vs Iz etc.

Eh? I'll have to test out the new forum's search facility, because I could have sworn that the point I made is one that you have made on a number of occasions in the past!

I am sanguine about using 20A rated switches, because 20A is the most that's allowed to be carried by the cable. I have a much harder time with 16A ones.

Even when there is a 13A (or smaller) fuse in the current path through the switch?

Kind Regards, John

 

[ban-all-sheds]

The problem there is what are the terminals rated at, given that they have to pass the circuit current, not just the load. Yes, you can say, with much validity, that they don't have to because the in and out conductors will be in contact, but there's no rigour in that. With 20A rated accessories you know that the terminals must be OK.

Put it this way - if you were using choc-block to create a spur from a ring final would you use 15A rated stuff?

 

[JohnW2]

The problem there is what are the terminals rated at, given that they have to pass the circuit current, not just the load. Yes, you can say, with much validity, that they don't have to because the in and out conductors will be in contact, but there's no rigour in that. With 20A rated accessories you know that the terminals must be OK.

Only 'for long periods' ... for periods which are not 'long' (whatever!), anything up to the current allowed to flow by the 32A OPD could (seemingly 'compliantly') be travelling through any particular bit of cable in a ring, hence also 'through' (very little, really!) the terminals of anything 'in the ring'.

However, I confess that I'd forgotten details of the context, and wasn't thinking of quite the right situation. I was thinking a a situation in which the switch was not 'on the ring' but, rather, interspersed in a spur from a ring. In that situation, and if the switch were only serving an FCU or single socket, would you then agree that a 16A switch would be more than adequate?

Put it this way - if you were using choc-block to create a spur from a ring final would you use 15A rated stuff?

I probably wouldn't, but primarily because of the size of the holes into which to (try to) get the conductors! I must say that I've never really understood how the 'current ratings' of things like chock-blocks are arrived at. In terms of current 'going through' the terminal (from one side to the other) I would have thought that the CSA of the brass (or whatever) in a "15A" one would be good enough for an awful lot more than 15A, wouldn't it?

Kind Regards, John

 

[ban-all-sheds]

I was thinking a a situation in which the switch was not 'on the ring' but, rather, interspersed in a spur from a ring. In that situation, and if the switch were only serving an FCU or single socket, would you then agree that a 16A switch would be more than adequate?

Can't think why not.

I probably wouldn't, but primarily because of the size of the holes into which to (try to) get the conductors!

I did pluck that size out of the air - TBH I don't know how tight a squeeze it would be.