problems getting SWA into a CU mounted on plasterboard.

[jpadie]

Happy Easter to the lot of you! 

 

I come in search of some more collective wisdom to solve a problem in the "proper way"....

 

I'm installing 16mm2 SWA to a garden room.  I've gone through the outer wall at a very steep angle to try to minimise the bend radius.  But even then the rigidity of the SWA is such that as soon as I put the CU on to the wall the CU gets ripped off the plaster, drywall anchors and all.  What's worse is that the area is already decorated... Pic below.   

 

for the drywall anchors I've used standard rawlplugs and the easyfix type.

 

I have some constraints that have to be observed:  

(a) I cannot bring the cable in much lower as I need to leave width to get an immersion heater in/out.  

(b) I cannot get the CU to match up to any installed battens.  

 

My thoughts so far have been:

 

1.  give up.  take the swa to an adaptable box on the outside of the garden room and use the hole to take some 16mm t+e through a conduit and up the inner surface of the plaster board.   I might be able to fish the cable up and bring it through the main cable pass although I'm not holding my breath that it would be any easier.

2.  use really heavy duty drywall anchors and try again.  

3.  it's _just_ possible that I might be able to get some 19mm batten material horizontally through on either side of the cable channel hole.  Could do this and try again.

 

overall, I'm leaning towards solution 1 as I can't, in honesty, see how I can make it work reliably.  feels like this gauge of SWA is better suited for bricks than plasterboard!  

 

thanks in advance for your thoughts.

justin

 

 

[stu w]

Strip the swa right back to the wall , put the cable into a 45 conduit elbow, then into the bottom on the CU 

[ProDave]

I would never mount a CU on plasterboard fixings.

 

Mark out the exact size of the CU on the wall, cut that shape out of the plasterboard, and extend the cut out sideways to reach the centre of the adjacent studs.

 

Fill your hole now with a sheet of at least 12mm plywood, securely fixed to the adjacent studs.  Fix CU to plywood.  I would probably even attach a batten to the inside of the plywood in line with the mounting holes so the screws can go through the plywood into the batten.

 

Fill joints and paint plywood.

[jpadie]

On 01/04/2024 at 12:31, ProDave said:

I would never mount a CU on plasterboard fixings.

 

Mark out the exact size of the CU on the wall, cut that shape out of the plasterboard, and extend the cut out sideways to reach the centre of the adjacent studs.

 

Fill your hole now with a sheet of at least 12mm plywood, securely fixed to the adjacent studs.  Fix CU to plywood.  I would probably even attach a batten to the inside of the plywood in line with the mounting holes so the screws can go through the plywood into the batten.

 

Fill joints and paint plywood.

 

 

Thank you.  That worked well and I may also use the same solution to mount a mini split unit whose rear mounting bracket is only 350mm wide.  The instructions say to use wall plugs but I suspect it expects to be mounted on masonry.