How far between back to back backboxes

[Adam_151]

Am I right in thinking you shouldn't flush two boxes in, at the same spot in opposite sides of the wall? How far so they need to be offset.

Got a data point to flush into the wall, the cat5 comes straight through the wall from a data point behind and then both run in the same conduit (be much easier if they could just be spur'ed )

Boxes are 25mm , wall is block

 

[cozycats]

I haven't seen any rules on this one but I would try to offset them by at least the thickness of the wall but no more than 150mm to ensure that everything was within zone, but maybe I'm just being overly cautious!

 

[RF Lighting]

I think the only reason for offsetting boxes is so that you don't end up just punching a box sized hole through the wall, and also to make sure there is enough brick / block to fix to. I am not sure if there are any rules / regs regarding the weakening of the wall structure. Assuming it is a 4" block wall a would have thought that an offset of 1½ - 2" should be OK but I may need correcting.

 

[securespark]

Well, if you have a 100mm wall, with plaster of approx 12mm on each side, you will only have to dig out 26mm of brick or block in total;, if 2 25mm boxes are back to back. Add the depth of two 32mm screws and you have a total of 114mm....

 

[SparkyMarky]

I've actually got the same thing in the room I'm in at the moment. The lightswitch is back to with the lightswitch for the room next door, in a 4 inch cinder block wall. I had to fit a 35mm backbox on this side for a deeper switch a couple of years ago. Admittedly I had to go carefully (I didn't feel it was a job for the SDS chisel!), but I managed to chop enough wall out to fit it without breaking right through...

 

[Lectrician]

Cat5e spec calls for deeper boxes than 25mm