Can I cut the corner off a back box (conduit in way) ?

[banjo67xxx]

I'm installing a single back box adjacent to an existing double socket, but the conduit containing the ring is buried right in the wall in the way.

Here's a photo of it. The red lines outline the brown conduit, and the green lines indicate where the 2.5mm cables enter the existing double back box.

Its not going to be easy to shorten the conduit without damaging the wires inside, so is the best solution to cut the corner off the back box so I can fit it over the conduit?

Also, as there is a cavity behind the lower half of the back box, what would you recommend to give it more structural strength?

 

[Taylortwocities]

You'll be fine to do that. Watch out for jagged edges on the end of the conduit though.
EDIT: But why not just have the box further to the right, then you don't have to chop it about?
EDIT2: That box looks too shallow for an FCU. I would have a 35mm box in there.


PS As its only an FCU going in there, so you'll not need that much strength. Just use some morter to position it in the wall and secure with a screw through the back once its set.

 

[Aragorn84]

Very careful application of a hacksaw might see the conduit shortened without damaging the wires.

Only last week i cut and removed some sections of lighting conduit without damaging the cables within.

If it were me, i'd feel compelled to shorten the conduit and install a proper dual backbox like this:

http://www.tlc-direct.co.uk/Products/AP540.html

 

[JohnW2]

Very careful application of a hacksaw might see the conduit shortened without damaging the wires. nly last week i cut and removed some sections of lighting conduit without damaging the cables within.

I have also been known to do that, but I'd probably be hesitant to suggest that anyone else should try!

If one does try it, and there is adequate space available, the safest approach is probably to slide some suitably-sized metal tubing (flexible if you have it!) over the conductors and into the conduit to beyond the 'cutting point'.

Kind Regards, John

 

[sparkwright]

Would really be inclined to
a) move the new box to right 2 inches, so there's a gap between the boxes.
b) put the new box to the left of the double box.

Anything else is going to be a struggle, or a risk of damaging cables, or a bit of a bodge.

That 25 mm deep single box is deep enough, though as suggested, a deeper box would be easier for connecting up, particularly for the inexperienced.

 

[banjo67xxx]

Would really be inclined to
a) move the new box to right 2 inches, so there's a gap between the boxes.
...
That 25 mm deep single box ...

Thanks I'll take yur advice and move the box 1/4inch to the right (no more wall to the left), and it will save the hassle of deepening the existing hole to 35mm and messing around with the conduit to use the 3-gang box Aragorn84 mentions.

You must have seen a lot of boxes to recognise its a 25mm from the photo

Does it make any difference which way I run the wires, out of the following 2 options?

a)
[code:1]
RIng ----- 2-gang socket ----- fused switch ----- Ring
|
IP66 single socket
[/code:1]
b)
[code:1]
RIng ----- 2-gang socket ----- Ring
|
fused switch
|
IP66 single socket
[/code:1]

 

[sparkwright]

If what you describe is correct, either method would be acceptable.

 

[OwainDIYer]

a)
[code:1]
RIng ----- 2-gang socket ----- fused switch ----- Ring
|
IP66 single socket
[/code:1]

would be preferable as (a) the Fused switch would be on the ring, not a spur, (b) you won't have 3 lots of cables into the 2-gang socket, which will make it a bit easier to wire up if the sockets have small terminals.

 

[333rocky333]

You must have seen a lot of boxes to recognise its a 25mm from the photo

The 20mm knockouts in the side help

 

[banjo67xxx]

If what you describe is correct, either method would be acceptable.

Thanks. I used (b) as it worked out easier to insert a third wire than move tail into a new box.

I've tested an appliance works from the new socket and can be switched on/off with the switch, and even though I checked each wire was firmly in place in the correct place I was wondering if there are any further tests I should make.

I could buy one of these testers ...
http://www.amazon.co.uk/Green-Mains...qid=1396466432&sr=8-2&keywords=socket+testers
but not a lot of point as I could do the same with my DMM. I'd expect 240-250V between L-N and L-E, and 0.1-5V between N-E.

Is there anything else I need to test (I think PAT testing is only done on devices you can unplug, and I havent got £235 for the test machine anyway) ?

Looking around, I think this answers my own question
http://www.tlc-direct.co.uk/Book/8.3.2.htm
and tells me how to do it