socket box depth

[Jupiter01]

Hi All,

Would a 25mm deep box suffice for a double gang light switch which will contain 4 light switches?

 

[AndyPRK]

yes.

If dimmers then check the depth required

 

[OwainDIYer]

I would go deeper if possible. A lot of cable can accumulate behind multigang switches.

 

[Taylortwocities]

I agree. I'd always go for deeper.
32mm or so.

 

[Tigercubrider]

It is the heck of a lot easier to go deeper at the time than try to add depth later

 

[garyo]

Go as deep as you can... and especially if you ever want to fit the fancy brushed steel face plates.

 

[EFLImpudence]

There must be an awful lot of unnecessary work carried out.

Deep back-boxes in case you may need them one day even though your switch only needs a 16mm. one.
All sockets on a pointless ring, despite the increased Zs and cable cost, in case you ever want to spur of it.
10 mm² cable for cooker in case you ever want to install an industrial kiln.
Unnecessary number of circuits and spare ways in an eighteen way consumer unit in a three-bed-semi.
Unnecessary switches for all appliances.
Flow switch and relay for heating mirror.

 

[JohnW2]

All sockets on a pointless ring, despite the increased Zs ....

I would think it would be very unusual (if not unknown) for the Zs of a ring (pointless or not) to be higher than that of alternative radial arrangements, wouldn't it?

Kind Regards, John

 

[EFLImpudence]

Probably, but you know what I meant.

 

[JohnW2]

Probably, but you know what I meant.

I understand, and largely agree with, the rest of what your wrote, but I think it incredibly unlikely that a ring would have a higher Zs (or VD) than radial(s) serving the same sockets. In fact, unless the routing of the ring cable was absolutely crazy, I doubt that it would be even possible!

Kind Regards, John

 

[EFLImpudence]

Yes, you are undoubtedly right but it was a convenient way of wording "wasteful cable routing down to sockets and back along the same route".

I should have said "despite the unnecessary increasing of Zs", although then you could have said it probably doesn't matter.

 

[JohnW2]

I should have said "despite the unnecessary increasing of Zs", although then you could have said it probably doesn't matter.

I'm still confused. I still don't understand in what circumstances a ring serving a number of sockets could/would have a higher Zs than would radial(s) serving the same sockets. One would obviously usually expect the ring to have a considerably lower Zs.

Kind Regards, John

 

[EFLImpudence]

I'm not saying that. I'm saying the oft quoted 'it's better if all sockets are on the ring' rather than have spurs is, in general, a waste of cable.

I, mistakenly from your point of view, said this would (unnecessarily) increase the Zs.
I didn't say this would make it higher than a radial.

The same would apply to a radial.

 

[JohnW2]

I'm not saying that. I'm saying the oft quoted 'it's better if all sockets are on the ring' rather than have spurs is, in general, a waste of cable.

Yes, that will often be true.

I, mistakenly from your point of view, said this would (unnecessarily) increase the Zs. I didn't say this would make it higher than a radial.

I'm still a bit lost. If your 'increase' is not relative to a radial, what does it relate to. A spur from a ring will (I think inevitably, but certainly usually) have a slightly higher Zs than would the same socket (or whatever) if it were part of the ring, wouldn't it?

The same would apply to a radial.

What do you mean by that? As often discussed, unless in reduced CSA cable, the concept of a 'spur' does not really exist in relation to a radial.

Kind Regards, John

 

[EFLImpudence]

Come on John; sometimes I wonder.

I just said the philosophy of putting all sockets on the ring on the off chance that one day you may wish to spur off one of them was unnecessary work and a waste of cable.
Mentioning that it would increase the Zs was apparently a foolish thing to include.