Discuss 25mm Knockout Metal Clad Boxes. in the Electrical Forum area at ElectriciansForums.net

RDB85

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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.
 
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B

Bobster

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.


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.
 
S

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!
 

Megawatt

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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

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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?
 

Megawatt

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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

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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

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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.
 
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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

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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

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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

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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

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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

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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

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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.
 

RDB85

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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.
 
S

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

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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

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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

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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.
 

RDB85

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If the cable is neatly installed then it will look a lot better than a flexible conduit clipped to the wall.
As I say each to their own. The cable will be neat, I just wanted to try using some flexible conduit as I am new to all this. I am only installing it then a qualified spark is connecting it all up and testing it.
 

RDB85

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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.
I am not trying to insult anyone. It is not my style, words can be misinterpreted. But I am trying to build a portfolio of work, I am trying to show that I have used various cables and have added in some mechanical protection, although not needed, to me it looks better and more pleasing when in place.

Also I have seen this guy who is fully qualified use flexible conduit:
 

James

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I spent 14 years working for flexicon
There is not a lot I don’t know about flexible conduit
You say each to there own, it’s not something I would consider for a real job.
 

Megawatt

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I am not trying to insult anyone. It is not my style, words can be misinterpreted. But I am trying to build a portfolio of work, I am trying to show that I have used various cables and have added in some mechanical protection, although not needed, to me it looks better and more pleasing when in place.

Also I have seen this guy who is fully qualified use flexible conduit:
Rob I never said I never use flexible conduit. We run hundreds of feet of steel conduit. Example we have to run 200 feet of pipe to a transformer then I will set a tee, flex in the transformer. We have people that run conduit and it is level and plumb and it’s pretty good looking, even if you have parallel runs I have to say it looks good and if it didn’t they would have to go back and fix it so we can pull wire. Again things are a lot in different than what y’all do. Nothing bad but we just choose to run pipe
 

Megawatt

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RDB what you are saying is right especially attaching to a fence. But you could bury it if it’s cable approved for direct burying
I have attached conduit to a fence and it looked like crap so we got our trencher and run it under ground we like y’all take pride in our work
 
Black Flexible plastic conduit seems the buzz product with YouTuber electricians.
I must admit it does look better than mini trunking.
 

RDB85

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Black Flexible plastic conduit seems the buzz product with YouTuber electricians.
I must admit it does look better than mini trunking.
I believe YouTube electricians are not too popular on here. I think it looks nice as I say.
 

Andy78

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I'm not a fan of the plastic flexi pipe idea. I think it looks a bit of a lash up in that video.

If you're building a portfolio of work then non-combustible cable support for systems would be a good idea. Not sure if that gets addressed in the video as I've only skimmed it.
 

Megawatt

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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.
I believe YouTube electricians are not too popular on here. I think it looks nice as I say.
First of all I’m not a DIY I’m a master Electrician and have been since 2001 and I am in no kind of way trying to insult anybody we are just talking about the way UK and the USA do things I am not insulting nobody and y’all obviously are great at what y’all do.
 

RDB85

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I'm not a fan of the plastic flexi pipe idea. I think it looks a bit of a lash up in that video.

If you're building a portfolio of work then non-combustible cable support for systems would be a good idea. Not sure if that gets addressed in the video as I've only skimmed it.
I don’t think that does. Have you a link to the product. As I may use them rather than the conduit and clips.
 

Andy78

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I don’t think that does. Have you a link to the product. As I may use them rather than the conduit and clips.
Whichever wiring system you decide upon needs to comply with 521.11.201. There are many different methods of doing this.
 
I believe YouTube electricians are not too popular on here. I think it looks nice as I say.
I have no issue at all with celebrity youtuber sparkies.

Infact I quite admire how they can juggle being an electrician and youtuber celebrity at the same time.
 

Megawatt

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I have no issue at all with celebrity youtuber sparkies.

Infact I quite admire how they can juggle being an electrician and youtuber celebrity at the same time.
RDB it doesn’t matter what you think I know how to do electrical work and we are going to leave it at that. I’m done with this conversation and I’m surprised Dave hasn’t fussed yet cause we are way off on the main post. This is no competition
 

Andy78

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RDB it doesn’t matter what you think I know how to do electrical work and we are going to leave it at that. I’m done with this conversation and I’m surprised Dave hasn’t fussed yet cause we are way off on the main post. This is no competition
Why do you think all these posts are aimed at you ? They aren't. This is not your thread. You really need to pay attention.
 
@Megawatt I asked you yesterday not to side track these threads and you have done it again. Create your own threads if you want to pursue a different topic, I am locking you out of this thread to prevent further replies.
 

davesparks

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I am not trying to insult anyone. It is not my style, words can be misinterpreted. But I am trying to build a portfolio of work, I am trying to show that I have used various cables and have added in some mechanical protection, although not needed, to me it looks better and more pleasing when in place.

Also I have seen this guy who is fully qualified use flexible conduit:
Yeah he does, and it looks like a DIYer has been at it in my opinion, but maybe I'm a little old fashioned in my methods. The last shed I wired was done in bare MICC.
Flexible conduit is generally suitable for short links between fixed items of equipment and items which may have a bit of movement or vibration. For example you might use flexible conduit to go from an isolator to an adjacent fixed piece of machinery.

As far as mechanical protection goes flexible plastic conduit is mechanically less strong than the NYY-J cable so will offer no advantage in that instance.
 

RDB85

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Yeah he does, and it looks like a DIYer has been at it in my opinion, but maybe I'm a little old fashioned in my methods. The last shed I wired was done in bare MICC.
Flexible conduit is generally suitable for short links between fixed items of equipment and items which may have a bit of movement or vibration. For example you might use flexible conduit to go from an isolator to an adjacent fixed piece of machinery.

As far as mechanical protection goes flexible plastic conduit is mechanically less strong than the NYY-J cable so will offer no advantage in that instance.
I will probably just send it back, and go for the SWA clips if ones could be recommended. I just thought it may look a bit nicer, that’s all.
 

ipf

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I personally don't like 25mm metal tube and for the reasons above won't use it.

I can't think of a single time where I would use 25mm metal tube
It has it's uses, usually industrial, wiring 3 phase machines or multi switches....used loads over the years.
I came across some sockets, newish job, in a factory. For some reason they were done in 25mm. It looked a real mess, to tell the truth.....hardly a natural bend...all inspection elbows....yuk!.....and non RCD sockets....so to change they'd need re boxing and drilling out to suit.
 

davesparks

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I can't think of a single time where I would use 25mm metal tube
This seems like a very odd statement, surely you would use 25mm conduit or larger when the size, or number, of cables requires it?

The way I was taught to install a conduit system was to run a 25mm main run with 20mm taken from that to each switch, socket or other point. This is usually sufficient to get a ring, lighting circuit and a radial circuit through for a small installation.
 
This seems like a very odd statement, surely you would use 25mm conduit or larger when the size, or number, of cables requires it?

The way I was taught to install a conduit system was to run a 25mm main run with 20mm taken from that to each switch, socket or other point. This is usually sufficient to get a ring, lighting circuit and a radial circuit through for a small installation.
Sorry

I should have said in a domestic application
 

davesparks

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Sorry

I should have said in a domestic application
Ah right, in that case steel conduit is pretty rare full stop.
I've only used it in domestic a couple of times and they were in rather well equipped shed/workshop buildings and a stable block in a garden.
 

ipf

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Ah right, in that case steel conduit is pretty rare full stop.
I've only used it in domestic a couple of times and they were in rather well equipped shed/workshop buildings and a stable block in a garden.
Very rare. A couple of boiler houses in very large premises....with 3 phase supplies, for me.
Although, I have a couple of foot of it in my garage...…...intruders in mind.
 

GBDamo

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Your wholesaler will likely have step drills on the shelf
The best one ive used was a Rexel (£70-80 if memory serves me) own brand, they're great for stepping up existing holes in metal or new holes on plastic but they do suffer from losing their edge if you try to start a fresh hole in metals.
 
Trouble is all these cone/step drills will make the hole bigger concentrically, and that won't work if you're trying to enlarge the 20mm knockout on a metalclad socket.
 
A sheet metal punch will do an offset centred hole. Just make sure all three pointy bits are biting into metal and you haven't aligned one of the points inside the existing hole.
 

David Prosser

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You could try drilling a pilot hole then using a sheet metal punch if there a spot without a knock out that's convenient.

rsgaz beet me to it :)
 

RDB85

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Yes, they let you enlarge a hole like this...

Thanks, I might order one, as they look like they could do the job quite easily, not much mess either.
 

Pete999

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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.
You could enlarge the 20mm with a cone cutter, might work for you
 

Spoon

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To far away for a lasting relationship Andy, oh and thanks for the welcome back message
I don't think anyone would wish to have a lasting relationship with me... How could they cope...
 

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