Help with Surface Mount Patress Box Drilling for Conduit.

[TheConduitKing]

Hey everyone, how's it going?

I built myself a practice wall in my garage so that I can get more training in at the weekends from stuff I do in tech and on site.

The difficultly is drilling holes in the boxes and getting them centered and uniform.

Here is a link showing the drawing I've been following and how messed up my boxes are. ?

Conduit Boxes

Conduit Boxes album hosted in ImgBB

ibb.co

This is the boxes I've been using:

LAP 1-Gang Surface Pattress Back Box 46mm

Order online at Screwfix.com. LAP range combines great engineering with an elegant, slimline design. Supplied with fixing screw and covers. FREE next day delivery available, free collection in 5 minutes.

www.screwfix.com

I have only now found out that you can get them with knockouts. ?

Tower Mita 1-Gang Surface Pattress Surface Box 25mm

Order online at Screwfix.com. With 20mm knockout and mini knockout. Robust, heavy gauge material construction. For use with 20mm conduit systems. FREE next day delivery available, free collection in 5 minutes.

www.screwfix.com

But the problem is that they don't have any side knockouts.

Any advice on how I can measure the boxes to get the holes centered and in the same location across them all? In college the holes where already drilled and they didn't show us how to do it.

 

[westward10]

The LAP box isn't suitable for conduit entries even though you could probably make some with a holesaw it will be tricky as that type of box is prone to shattering. The Tower box won't have side entries due to the face plate fixing lugs so you are probably better off with metalclad boxes which will have entries to all sides.

 

[TheConduitKing]

box is prone to shattering.

Yup lol. Learned that the hard way.

The Tower box won't have side entries due to the face plate fixing lugs

Couldn't they just place the knockouts above the lugs on each side? That's where I've been drilling with limited success.

The Tower box won't have side entries due to the face plate fixing lugs

Surely there has to be some way of doing it. I'm guessing it's not a common way of doing things.

 

[snowhead]

You can drill the Tower type boxes, they're made of a softer plastic to the normal surface box.
And they don't have the T&E knockout weakspot at the back of the box, which is why yours have shattered.

 

[TheConduitKing]

You can drill the Tower type boxes, they're made of a softer plastic to the normal surface box.

That's a good shout. I'll get those from now on.

But then how do I get the side holes all the same. I'd just dvide the length of the box in half to get the center point and do the same with the depth.

But that would put me where the lugs are. So do I just divide the length again to get into the corners?

 

[TheConduitKing]

You can drill the Tower type boxes, they're made of a softer plastic to the normal surface box.
And they don't have the T&E knockout weakspot at the back of the box, which is why yours have shattered.

This is what I've done so far

PXL-20210204-114218572

Image PXL-20210204-114218572 in Conduit Boxes album

ibb.co

PXL-20210204-114223243

Image PXL-20210204-114223243 in Conduit Boxes album

ibb.co

 

[FatAlan]

If I was wiring a garage with surface mounted wiring in PVC conduit I'd just go for metal clad boxes.

 

[snowhead]

But then how do I get the side holes all the same. I'd just dvide the length of the box in half to get the center point and do the same with the depth.

But that would put me where the lugs are. So do I just divide the length again to get into the corners?

You need the midpoint of the space between edge of the box and central lug.
And low enough in the box so you can't get your fingers down the back of the conduit against the wall or board.

To get all the boxes the same, stack them all up against each other and mark a line across all of them.

Example of side position below, nicked from link below that,

 

[7029 dave]

I would use metal clad, your entries are all over the place, like your over saddle well done.

 

[TheConduitKing]

Thanks mate. That's very helpful. I'll give it a go and report back!

 

[TheConduitKing]

I would use metal clad, your entries are all over the place, like your over saddle well done.

Gonna give what snowhead suggested a go and see how it turns out.

"like your over saddle well done."

Thanks! Took me a couple attempts because I wasn't keeping it straight over my knee and it kept warping. Got it eventually though!

Need to redone my 90. It's slightly off.

 

[7029 dave]

TIP, get some friction on the tube by rubbing it before you pull your set. (it warms/softens it up)

 

[TheConduitKing]

TIP, get some friction on the tube by rubbing it before you pull your set. (it warms/softens it up)

Aye, that's what I've been doing. But it's so cold in my garage that the conduit ripples when I bend it. But I am using heavy gauge pipe with a heavy spring.

So it's probably just me. ?

 

[7029 dave]

Aye, that's what I've been doing. But it's so cold in my garage that the conduit ripples when I bend it. But I am using heavy gauge pipe with a heavy spring.

So it's probably just me. ?

Good Good

 

[FatAlan]

Just follow the lazy Youtube sparks and use flexi conduit on everything. I've just finished a garage extension and did it in 20mm galv. Good fun but had to borrow a Hilmore and die set from a mate as I can't justify investing in that kit yet.