Terminal Box Wiring Coming Through Wall for Conduit

[h901]

hi

is there a steel terminal box that caters for wires coming from inside to outside, all the terminal boxes i've found don't have holes at the back. i was just wondering what would be the correct way to feed a wire through the wall into a terminal box (then through conduit to a camera outside) do i just drill a hole through the box?
hope it makes sense

thanks

 

[drzsta]

Yes you need to drill a 20mm hole through the wall and take the conduit through if your going to be doing it properly.

 

[Andy78]

Or a 22mm hole if you want the conduit to fit without a hammer, widened to 25mm at the ends to accommodate the steel box spout/coupler depending on how you connect it.

 

[KennyKen]

Sometimes having a small piece of conduit for a wall void can be a nightmare espically when threading both ends... that's why they invented nipples. (Threads)

 

[Deleted member 26818]

What is normally done in this situation, is two boxes with 20mm holes drilled in the back, then a short length of conduit between the wall connected to the boxes with couplers and bushes.
Using boxes with the rear entry spouts would be more robust, and probably provide a better seal against the ingress of moisture.

 

[h901]

Appreciate all the replies, thanks

Never had to drill a 20mm hole, would an sds drill with sds drill bit be able to do this size without problem?

 

[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?