Double Socket off a spur?

[NigelCollins]

I want to install a second double socket in the garage. The current arrangement in the garage is as follows:

Double socket fed from an RCD (B16).

From the double socket a spur has been taken (2.5mm T&E) for the supply to a gas boiler.

I assume regs wont let me take a further 2.5mm spur from the gas boiler spur?

If not what other options do I have as I presume I cant run an additional socket as a second spur from the original double socket.

The original double socket is fed by a single 2.5mm T&E from RCD and nothing else is on that RCD.


The extra double socket I want to install is for running a variety of woodworking tools where maximum load will be about 1400W. I will use the second socket to occasionally charge battery for cordless drill (40W) so maximum load will never exceed 2000W (8A). The boiler consuption is 150W.

Thanks

 

[JohnW2]

I want to install a second double socket in the garage. The current arrangement in the garage is as follows: Double socket fed from an RCD (B16). From the double socket a spur has been taken (2.5mm T&E) for the supply to a gas boiler. I assume regs wont let me take a further 2.5mm spur from the gas boiler spur?

If I understand correctly, you do not have 'spurs' - you simply have a radial circuit, and you can connect as many sockets (and/or connection units) to that circuit as you wish - either in a 'straight line' ('daisy-chained') or as branches (i.e. two coming from one place), provided it's all done in adequate cable (2.5mm² is fine). The total power you will be able to draw is, of course, limited to the 16A dictated by the B16 (I assume MCB or RCBO, not RCD). Certainly any new, and ideally all, the sockets need to be protectedby an RCD (as well as MCB), or an RCBO.

Kind Regards, John

 

[NigelCollins]

Thanks for response. Sorry yes its an MCB protecting the circuit.

So the easiest way, from a distance point of view, is to run a short piece of 2.5mm T&E from the fused outlet for the boiler. I will run in plastic conduit.

Many thanks for your help.

 

[EFLImpudence]

Double socket fed from an RCD (B16).

Terminology already covered but -

do you mean at the house consumer unit?

 

[NigelCollins]

Hi - yes from the house consumer unit

 

[EFLImpudence]

That's fine, then.

I just thought that the origin of the circuit hadn't actually been stated.

 

[Taylortwocities]

Adding another socket to the B16 protected radial ios fine.
There should be an FCU between the supply and the boiler limiting the current to what is required by the boiler manufacturer. Usually a 3amp fuse.

 

[JohnW2]

There should be an FCU between the supply and the boiler limiting the current to what is required by the boiler manufacturer.

That would presumably be the "fused outlet for the boiler" to the supply side of which the OP plans to connect his new socket

Kind Regards, John

 

[DCC]

I thought I'd seen threads implying multiple sockets on a 16A Radial were frowned on - not for safety but because the regs only list a 20A Radial as one of the standard circuits?

 

[NigelCollins]

TTC - yes there is a 3A FCU between the supply and the boiler

 

[JohnW2]

I thought I'd seen threads implying multiple sockets on a 16A Radial were frowned on - not for safety but because the regs only list a 20A Radial as one of the standard circuits?

It's down to the designer to estimate the likely loading of the circuit. Even with a 20A MCB, a multiple-sockets radial could be vastly overloaded, and the 4A difference between that and a 16A MCB is really neither here nor there. Even the 20A radial is only mentioned in the 'informative' Appendix 15 of the regs. The example given in that Appendix includes 11 double sockets and one single socket - so, theoretically, an enormous potential loading in relation to a 20A MCB, but the desiner may well decide that 20A 'is enough' in a given situation.

Kind Regards, John

 

[DCC]

Sounds reasonable.