Not enough room in box for wiring & switch fcu

[Glyn1959]

Hi, I have a standard metal box sunk into a solid wall with a blanking plate being used as a junction box. I have utilised this to wire an extractor fan, changing the blanking plate for a switched fcu.
However, due to the addition of a third set of wires and the bulk of the back of the fcu there is not enough room.

My idea was to take a shallow surface mounted box, remove the back, drill out the bolt threads and then sandwich this between the fcu and the metal box held in place with longer bolts. This has proved to be very fiddly with the surface mounted box obstructing the fitting of the wires along with the lack of length in the wires themselves.

Other options I can think of are:
1. Spurring from the junction box to a separate box alongside;
2. Removing the existing metal box and replacing with a deeper one (this is not practical).

An ideal solution would be a surface mounted box (frame only) with a hinge at the top and clipped together at the bottom once in place would be ideal but I have never seen such a thing.

Any suggestions other than these would be appreciated before I decide on a plan of action.
Cheers

 

[JohnD]

2. Removing the existing metal box and replacing with a deeper one

best option

(this is not practical).

why not?

 

[Glyn1959]

Hi, it's a job for an elderly couple who have had the mess and noise of the fan installation and I do not want to give them any more by chiselling or drilling. I'm not being azt I genuinely want a clean (and quiet) alternative.
Cheers

 

[davy_owen_88]

Hi, it's a job for an elderly couple who have had the mess and noise of the fan installation and I do not want to give them any more by chiselling or drilling. I'm not being azt I genuinely want a clean (and quiet) alternative.
Cheers

Then extend the cables, fill in the recess and put a surface mounted box in its place.

 

[Glyn1959]

Hi, Thank you. Sometimes we can overlook the obvious and make the job more difficult than necessary!

 

[mattylad]

Isn't there an extension that you can get for single boxes?

I know that they are available for fire alarm call points etc, I'm sure I have seen them for switch plates too?
This may make the whole job a lot easier & quicker, just by extending the front of the Sw/FCU by 10mm or so using longer screws.

EDIT: Like this but made of Plastic. Must be one available in the UK somewhere.
Edit again: or the try the Mita 19mm Extension Collars or the Single Gang extension collar

 

[Glyn1959]

Cheers. I think the answer is a combination of the replies posted. The extension collar is what I was trying to make by taking the back off a surface mounted box, but far better to use something specifically made for the job and therefore not as brittle when tightening.

Shortening the existing ring main cables and connecting them with choc blocks and then taking a spur from the choc blocks to the fcu will create more space and only 2 sets of wires to the fcu.

It's good to talk

Cheers for all replies