MKElectric LogicPLus box installation

[Greg Olsen]

I have used a single switch box. It will have a single switch in it. It is 73mm square and 48mm deep. It inserts into a hole milled in the finished face of a square aluminium extruded post approx. 4" square and 8 feet tall. The cut out is 79mm square and the LogicPlus faceplate is 86mm square. The LogicPlus faceplate are hollowed out on the back and should be able to accommodate the electrical box not being installed perfectly flush with the post face. But by how much is what I need to know.

The electrical box I have pushes as far in as it can with the bracket I have designed for it. I am pretty sure I need to design different mounting brackets that allow the box to sit further into the posts so that the box is flush with the face of the post. But as the posts are sent pre-assembled here in Canada I have to have new posts made and new brackets made with the boxes installed here and FedExed to Singapore. I was trying avoid that expense.

 

[Echo the husky]

48mm deep is more than enough for a light switch, these are designed to (just!) fit in 16mm deep metal boxes! (Unless the switch is a dimmer switch) 35mm box would be more than ample for a 1 gang light switch, then use slightly longer cover screws.

But by how much is what I need to know.

1mm absolute maximum

 

[Greg Olsen]

Yeah if I could get 35mm deep boxes with a 10-13mm thick adjustable spacer they mount on which mounts on my existing bracket that would be great. My bracket is supposed to be 48mm back inside the post but is only 46mm back and that is why the electrical boxes sit too far out. I will have to make the spacer though.

 

[Echo the husky]

I take it you had to order the boxes from the UK?

 

[JohnD]

16mm is enough for a UK lightswitch. 35mm is more than generous for a socket, 25mm is enough with ordinary cable. 47mm is very capacious.

You have an extra complication, since the walls will be clad in MDF and I presume the switches have to be enclosed in a fireproof enclosure. If metal boxes are sunk into a plastered or rendered wall, it doesn't matter if the boxes are slightly below the surface because there will be plaster in the remainder. AFAIK Singapore rules are modelled on UK rules but you had better ask a local electrician. Singapore still uses UK sockets so probably the standard range of backboxes will be available there, I have an idea they are sometimes pop-riveted into metal partitions. Perhaps you could use back-out screws.

The common sizes are here:
https://www.tlc-direct.co.uk/Main_Index/Boxes_and_Enclosures_Index/Boxes_Flush/index.html

You might still want to explore the plastic boxes used with dry-lining as they can be pressed through holes in the plasterboard (or in your case MDF) and are secured by sprung lugs and a front flange.
https://www.tlc-direct.co.uk/Main_Index/Boxes_and_Enclosures_Index/Boxes_Dry_Lining/index.html

 

[Greg Olsen]

Yes electrical boxes most often installed in MDF. These particular ones are in nice anodized posts that sit exposed and not covered with anything between two MDF clad wall partitions every 4 feet. Nothing combustible for several inches either direction.
The ones you just pointed to with sprung lugs are something to think about for mounting in the MDF panels. Except that we brag our panels can be snapped off by anyone and replaced. So we mount the electrical boxes to the frame and there are accurate cutouts in the MDF, 'tiles' we call them, that fit around the electrical boxes. Thnx.
FYI our site:
http://www.dirtt.net/

 

[Greg Olsen]

Yes we ordered boxes from the UK and cannot get shallower ones here quickly enough. Am remaking the brackets and posts at the moment.

 

[Greg Olsen]

We have a new showroom in London England. I'll let you know when it opens. Thank you for your help everyone!

 

[333rocky333]

Did the box lugs not sit back in the box enough to allow you to somehow shave 1 or 2 mm off the front of the box when on site if needbe