25mm Knockout Metal Clad Boxes.

[RDB85]

I’m looking for some metal clad sockets. But I need 25mm knockouts. Does anyone know any surface mounted metal clad sockets that have them? MK do some nice ones but they are only 20mm knockouts.

 

[Spoon]

Can you not get a 25mm reamer and just make the holes bigger?

 

[Bobster]

RS PRO HSS Cone Cutter 20mm x 25mm | RS

uk.rs-online.com

I'd just make the hole bigger.

 

[RDB85]

That looks expensive from RS. Does look nice though. Would this work: 2Pc Taper Reamer Set - Deburring Enlarging Aligning holes in Cast & Sheet Metal 5060028093694 | eBay - https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F111389733752

 

[Bobster]

That looks expensive from RS. Does look nice though. Would this work: 2Pc Taper Reamer Set - Deburring Enlarging Aligning holes in Cast & Sheet Metal 5060028093694 | eBay - https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F111389733752

Would take you ages using one of those.

The RS link was just the first cone cutter that came up on google. Aldi or Lidle usually have sets of 3 or 4 sizes for less than a tenner.

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Would be better for you, wont last long going through any decent metal, but the soft metal back boxes are made from will be no issue.

 

[Dustydazzler]

Run 2 x 20mm conduits instead

 

[RDB85]

Run 2 x 20mm conduits instead

I’ve already got the 25mm knockouts and 25mm conduit and clips. Be a pain sending them all back to TLC. I will just make the hole bigger.

 

[davesparks]

That looks expensive from RS. Does look nice though. Would this work: 2Pc Taper Reamer Set - Deburring Enlarging Aligning holes in Cast & Sheet Metal 5060028093694 | eBay - https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F111389733752

Your wholesaler will likely have step drills on the shelf

 

[RDB85]

Your wholesaler will likely have step drills on the shelf

I’ve found ones on eBay. Three sizes £10 posted. Should be okay.

 

[Silly Sausage]

You could always use reducers, couplers and nipples, but it could start getting a bit pricey if you've got a few to do!

 

[Bobster]

I’ve found ones on eBay. Three sizes £10 posted. Should be okay.

Just make sure that one of the steps is 25mm and not a step gap of 22/24/26 etc...

 

[Megawatt]

I’m looking for some metal clad sockets. But I need 25mm knockouts. Does anyone know any surface mounted metal clad sockets that have them? MK do some nice ones but they are only 20mm knockouts.

In the USA parts houses have 1/2 to 2 inch knockouts, and you can even get them for stainless steel. If you get on the internet and look up City electric supply or electrical distributors inc.

 

[davesparks]

In the USA parts houses have 1/2 to 2 inch knockouts, and you can even get them for stainless steel. If you get on the internet and look up City electric supply or electrical distributors inc.

Something must be getting lost in translation here, to us a knockout is basically a pre punched hole in an enclosure.
What is a knockout in your terminology? Do you have a picture?

 

[davesparks]

Just make sure that one of the steps is 25mm and not a step gap of 22/24/26 etc...

That's what lockrings and washers are for isn't it?

 

[Megawatt]

Something must be getting lost in translation here, to us a knockout is basically a pre punched hole in an enclosure.
What is a knockout in your terminology? Do you have a picture?

Dave a knockout is a tool to knockout holes and to close up a hole we call a them hole seals. Sorry about the confusion

 

[James]

A word of caution.

Lots of metalclad sockets are too shallow to get a 25mm thread into without it interfering with the socket face as you put it on.

Side entry is a no chance

Top or bottom you might get away with if you are using a female conduit coupler and a bush but not if you are coming into the box with a male thread and locknut.

Rear entry shouldn’t be a problem.

Also, if this is metal conduit, you need to make sure the hole center will be in the right place when the conduit is fastened to the wall so as not to require the socket to be spaced off the wall.

 

[RDB85]

A word of caution.

Lots of metalclad sockets are too shallow to get a 25mm thread into without it interfering with the socket face as you put it on.

Side entry is a no chance

Top or bottom you might get away with if you are using a female conduit coupler and a bush but not if you are coming into the box with a male thread and locknut.

Rear entry shouldn’t be a problem.

Also, if this is metal conduit, you need to make sure the hole center will be in the right place when the conduit is fastened to the wall so as not to require the socket to be spaced off the wall.

Thanks, this is the conduit that I have: 25mm Flexible Conduit Pack c/w 10 Glands - Black - https://www.tlc-direct.co.uk/Products/AF25BSB.html

The cable I am using is 4mm NYY 3 Core cable. I went to a few wholesalers who said that I would need 25mm PVC Glands and would be best with 25mm Conduit, as 20mm would be too tight on the glands and the conduit would be a pain to pull the cable through, would be better with the bigger conduit and glands.

 

[Dustydazzler]

I personally don't like 25mm metal tube and for the reasons above won't use it.
I had a school job where I tried to use it for the switch drops and it was a right pain.
The main electrician agreed and we changed the spec to using 2x20mm drops instead. The 2x20mm worked out a tiny bit more on materials but the installation was so much better.
I can't think of a single time where I would use 25mm metal tube

 

[RDB85]

The cable I am using is 4mm NYY 3 Core cable. I went to a few wholesalers who said that I would need 25mm PVC Glands and would be best with 25mm Conduit, as 20mm would be too tight on the glands and the conduit would be a pain to pull the cable through, would be better with the bigger conduit and glands.

 

[Megawatt]

The cable I am using is 4mm NYY 3 Core cable. I went to a few wholesalers who said that I would need 25mm PVC Glands and would be best with 25mm Conduit, as 20mm would be too tight on the glands and the conduit would be a pain to pull the cable through, would be better with the bigger conduit and glands.

Do y’all have rolls of wire you can buy instead of cables. My experience with European equipment only has cable that comes with the machines, then you have to over size the conduit just to pull the cable. We in the USA have to protect the cables according to the NEC. They are certain installations that we don’t have to run pipe. In the USA I would say that 50% of electrical work here is running conduit to get wires from point A to point B

 

[davesparks]

The cable I am using is 4mm NYY 3 Core cable. I went to a few wholesalers who said that I would need 25mm PVC Glands and would be best with 25mm Conduit, as 20mm would be too tight on the glands and the conduit would be a pain to pull the cable through, would be better with the bigger conduit and glands.

I may have missed something here but why are you installing NYY in flexible conduit? That seems like a very weird design to me, what's the purpose of the conduit?

 

[davesparks]

Do y’all have rolls of wire you can buy instead of cables. My experience with European equipment only has cable that comes with the machines, then you have to over size the conduit just to pull the cable. We in the USA have to protect the cables according to the NEC. They are certain installations that we don’t have to run pipe. In the USA I would say that 50% of electrical work here is running conduit to get wires from point A to point B

As a basic overview:
We use single insulated conductors in conduit and trunking, which I would assume is the same thing you are referring to as wire.
We use insulated and sheathed cables if not enclosed inside conduit and trunking, these cables can include armour or other types of earthed metal shield. Depending on type and conditions these can be installed clipped directly to walls, tied to cable tray or ladder rack, buried etc etc

What the OP is doing sounds unusual and I can only assume they have a reason for doing it this way.

 

[James]

That cable is 13.1mm diameter
M20 fitting has a 15mm hole
20mm flexible conduit has a 14.1 bore

You should have no problem pushing 5m down by hand or even 10m with a draw wire.
If you do it when it’s a straight line.

Alternatively use singles down the conduit?

 

[RDB85]

I may have missed something here but why are you installing NYY in flexible conduit? That seems like a very weird design to me, what's the purpose of the conduit?

I just wanted to use conduit as its going in a shed. I know its not needed but I just wanted to try it, plus it looks neater and cleaner than having a black cable clipped to wood.

 

[Dustydazzler]

Just clip it direct

You are just wasting money on flexible tubing in a shed

 

[RDB85]

Just clip it direct

You are just wasting money on flexible tubing in a shed

Each to their own. It looks awful clipped. As I am using it to build up a portfolio of work. Not just lashing cables in a shed for quickness.

 

[Silly Sausage]

Each to their own. It looks awful clipped. As I am using it to build up a portfolio of work. Not just lashing cables in a shed for quickness.

In that case, take everything back and do it in 20mm tubing and singles.

 

[davesparks]

I just wanted to use conduit as its going in a shed. I know its not needed but I just wanted to try it, plus it looks neater and cleaner than having a black cable clipped to wood.

If the cable is neatly installed then it will look a lot better than a flexible conduit clipped to the wall.

 

[RDB85]

In that case, take everything back and do it in 20mm tubing and singles.

I got the NYY Cable off a friend for nothing. It was an off cut that he said would be perfect for a shed. I will take the 25mm Conduit and Clips back, that's not a problem. It was what the guys in the Wholesalers used. Turns out I can use 20mm. A little lesson learnt.

 

[davesparks]

Each to their own. It looks awful clipped. As I am using it to build up a portfolio of work. Not just lashing cables in a shed for quickness.

Yes it is each to their own to a certain extent, but most of us would look at an installation which appears to be all flexible conduit clipped to a wall and assume it has been done by a DIYer.

Being a trainee earns you a fair amount of slack as far as replies to your posts go, but that is really getting quite close to insulting quite a few people and might make people less inclined to try and help.