Sockets & Lights

[salawiner]

Hi all, a bit of an odd one (trying to save money again!)

I have a garage which is attached to my property with a fluorescent light inside. I have traced the cable for this back to the fusebox, and for some reason it was run in with 2.5mm T&E with a dedicated 10A fuse.

I want to put a socket in the garage, and as there is already a dedicated fuse and 2.5mm cable - would it be acceptable to change the fuse to a 32A, then divert the cable in the garage to a socket, then from there to the light?

 

[Robin0577]

Is there an RCD protecting the circuit? The new socket will require 30mA RCD protection.

A 20 Amp MCB would normally be the maximum size for a 2.5mm radial circuit, not 32 Amp

The lighting part of the circuit should then be fused down further to 5/6 Amp. This could be achieved by using a switched fused connection unit as the light switch.

The new wiring will need to be properly tested

 

[salawiner]

Is there an RCD protecting the circuit? The new socket will require 30mA RCD protection.

A 20 Amp MCB would normally be the maximum size for a 2.5mm radial circuit, not 32 Amp

The lighting part of the circuit should then be fused down further to 5/6 Amp. This could be achieved by using a switched fused connection unit as the light switch.

The new wiring will need to be properly tested

Thanks for the info - seems obvious to use a fused switchplate for the light switch, don't know why I didn't think of it - there is already another similar to this for the outside security light.

As for the question regarding an RCD - lets just say I have fusewire on my shopping list! The replacement of the fusebox is (high) on the list of things to do, but this and another lighting circuit are lesser items that I can get done now.

 

[PrenticeBoyofDerry]

How far from the fuse board is the garage? As you must account for any voltage drop before you can decide what load the 2.5mm2 cable can carry.
Also a requirement for 30mA RCD on any newly installed socket.
This can be achievable be installing either a 16A or 20A MCB or RCBO the RCBO will then offer RCD protection, alternatively an RCD unit can be fitted at the intersection of any new cable if buried or at the socket outlet if cable surface mounted in the garage.

There are composite units that can be used as both a fused connection unit and an RCD.

 

[salawiner]

How far from the fuse board is the garage? As you must account for any voltage drop before you can decide what load the 2.5mm2 cable can carry.
Also a requirement for 30mA RCD on any newly installed socket.

The cable length from fusebox to light switch (where the socket will be) is around 10m. The RCD will be installed when the fusebox is replaced, which may well be before this work is done - I was just wanting to clarify the options.

 

[PrenticeBoyofDerry]

How is the cable routed to the garage?
If there are no additional de-rating factors to the circuit, such as routed in containment or through thermal insulation, it is likely that a 20A protective device can be used at the fuse board. You could then down fuse by use of a FCU for the lighting and also if cable is surface mounted to new socket, have an RCD protected socket plate fitted or you could introduce an RCD unit prior to the outlet. Please note any newly buried cable at a depth less than 50mm and not mechanically protected requires RCD protection as does any newly installed socket.