Terminal Box Wiring Coming Through Wall for Conduit

[DPG]

Yes, an SDS drill will easily drill a 20mm hole in brick or blockwork. Won't even need an SDS one if it's blocks and soft brick! Daz

 

[uksrevivor]

Use a long 8mm or 10mm pilot drill first then drill through from both sides with the 20mm drill it will avoid smashing the external brickwork and making a mess. Im assuming its a cavity wall.

 

[DPG]

Good advice. Hate to see blown out bricks. Daz.

 

[Taylortwocities]

Someone should tell the SKY and BT installers about that tip

 

[Andy78]

Someone should tell the SKY and BT installers about that tip

Who needs to be careful when you can just hide the mess under a wall grommet and a fistful of silicone ?

 

[h901]

Cheers guys, need to buy a 20mm drill bit now

 

[HandySparks]

Cheers guys, need to buy a 20mm drill bit now

As Andy78 says, you may find that you won't get a 20mm conduit through a hole drilled with a 20mm bit without a struggle. I think the reason is that the tip is usually slightly bigger than the rest of the drill, so the hole can wander or curve. I keep a cheap 22mm bit to poke through in those cases where the conduit is tight.

To avoid blowing the face off bricks, which can happen even with a small diameter SDS drill bit, I've started using a 22mm diamond core bit for some walls. Works quite well and is guaranteed not to damage the wall.

 

[h901]

As Andy78 says, you may find that you won't get a 20mm conduit through a hole drilled with a 20mm bit without a struggle. I think the reason is that the tip is usually slightly bigger than the rest of the drill, so the hole can wander or curve. I keep a cheap 22mm bit to poke through in those cases where the conduit is tight.

To avoid blowing the face off bricks, which can happen even with a small diameter SDS drill bit, I've started using a 22mm diamond core bit for some walls. Works quite well and is guaranteed not to damage the wall.

Good advice. So would it better to buy 20mm for main use but as you said a cheap 22mm just in case I need it. Or should I just get a 22mm (I don't want the hole to be too big though)

The diamond core drill bit is that used to internal wall or external (or both) - (sorry never needed to use one before)

 

[HandySparks]

Good advice. So would it better to buy 20mm for main use but as you said a cheap 22mm just in case I need it. Or should I just get a 22mm (I don't want the hole to be too big though)

It was just how it worked out for me. I already had the 20mm. 22mm is guaranteed to be big enough. Not really a problem unless you're trying to put some fixings really close to the hole perhaps. If anyone knows where I can buy a 21mm, I recon that would be purfect.

The diamond core drill bit is that used to internal wall or external (or both) - (sorry never needed to use one before)

Both.
You need to use a pretty high drill speed to make reasonable progress as it's such a small drill diameter for a core bit.

 

[h901]

It was just how it worked out for me. I already had the 20mm. 22mm is guaranteed to be big enough. Not really a problem unless you're trying to put some fixings really close to the hole perhaps. If anyone knows where I can buy a 21mm, I recon that would be purfect.


Both.
You need to use a pretty high drill speed to make reasonable progress as it's such a small drill diameter for a core bit.

Cheers

Oh ok, what drill do you use the diamond core drill bit with?

 

[Andy78]

A 22mm bit is the standard tool for 20mm conduit. Slight wanderings of the drill bit will make putting 20mm tube through a 20mm hole a right pain.
As my bit boxes are currently in the house I just popped and did some measuring for you:
Galv box spout O/D - 25mm
Galv coupler O/D - 22mm
Brass bush O/D - 25mm (at widest)

Hope this helps

 

[h901]

A 22mm bit is the standard tool for 20mm conduit. Slight wanderings of the drill bit will make putting 20mm tube through a 20mm hole a right pain.
As my bit boxes are currently in the house I just popped and did some measuring for you:
Galv box spout O/D - 25mm
Galv coupler O/D - 22mm
Brass bush O/D - 25mm (at widest)

Hope this helps

You're a legend, I appreciate the help. Cheers

Based on the above would it be wise to get a 22mm long bit for the conduit and then a 25mm (or 26mm) to make space and the openings for the spouts?

 

[HandySparks]

Cheers

Oh ok, what drill do you use the diamond core drill bit with?

Marcrist Drilling Machine DDM1, Core Drill City - http://www.coredrillcity.co.uk/product_info.php?cPath=1_22_44&products_id=494

The higher of the two speeds suits the small bits.

 

[Andy78]

You're a legend, I appreciate the help. Cheers

Based on the above would it be wise to get a 22mm long bit for the conduit and then a 25mm (or 26mm) to make space and the openings for the spouts?

That's what I do, piloted with a 10mm to start. I like the idea of a small core drill though I must say.....

If you will be buying the 25mm just for the end couple of inches, you may find it cheaper just to get creative with a small chisel, unless you need a 25mm bit for the future.

 

[Andy78]

This should start you off cheaply ...... Long SDS bits usually cost about this much per each ...

Clarke CHT705 5 Piece 600mm SDS Drill Bit Set - Machine Mart - Machine Mart - https://www.machinemart.co.uk/p/clarke-cht705-5-piece-600mm-sds-drill-bit-set/

 

[h901]

Just resurrecting this thread as I have a similar question and thought it'd be better to do it this way instead of starting a new thread.

As suggested by others on here, I've been using the box with the rear spout and it's worked well. But I've got a job that needs around 10 wires all to enter the same point (each wire is 6mm). If I use the above method that would mean 5 boxes with rear spouts and for some reason it doesn't seem the right way. Any ideas or help is much appreciated. Thanks in advance

 

[freddo]

Use larger conduit, up to 2" conduit and fitting are available here. no rear spout boxes, so drill the back of a box and fit a bush and coupler. Though finding the conduit tools might be harder, I have a stock, dies and a bender that will do up to 2", but they are not common items any more.

View attachment 35753

 

[Midwest]

34 posts on how to drill a hole through a wall, should of looked at this thread;

Pete's Videos - How to drill a hole - http://www.electriciansforums.co.uk/threads/how-to-drill-a-hole.119540/

 

[h901]

Use larger conduit, up to 2" conduit and fitting are available here. no rear spout boxes, so drill the back of a box and fit a bush and coupler. Though finding the conduit tools might be harder, I have a stock, dies and a bender that will do up to 2", but they are not common items any more.

View attachment 35753

Wowza, nice set of kit. Thanks for your help