32mm Holesaw in Metal Consumer Unit knock out - balls up!

N

Noob2013

Hi all,

I was dreading drilling a 32mm hole in the top of a Hager metal Consumer Unit for a 25mm Swa. There are square knock outs all along the top and my worse fear was the knock out coming out.

Anyway, there is limited room so I had no choice but to terminate the swa in the consumer unit.

I started drilling the hole and all was fine until the very last bit - the knock out came out!

So I now have one of the square knock outs in the top of a hager board missing with a half circular hole.

Possible due to lack of experience but how can I gland the swa now?

I was thinking I could have a square piece of metal either side of the costumer unit with a 32mm hole in each to fix it securely.

Any ideas much appreciate
 
I don't have an answer but have been pondering this one too!

Shame the CU manufacturers don't have answers and more shame to the IET for implementing such a stupid reg
 
Terminate into a metal box first which is up against the hole and feed cable through there. Feel for ya lol
 
I think, if possible I'd take a jig saw to the top of the CU and take out or put as big a slot in the top as I could and then plate it with some metal sheet, maybe cutting something like a piece of trunking or adaptable box lid. then terminate the armoured into it and possibly slot the rest for any sheathed cables. Just be careful you get rid of sharp edges, grommet strip or maybe piece of Truflex? and make it look as good as you can? Barrie
 
Cheers for the advice.

I think I'll try the idea me and Leesparkykent had with use a piece of metal.

I just had a thought, the large oval knock outs I took out for rear cable entry are big enough and will look better as they are the same colour and finish as the consumer unit
 
Plate is the only realistic way forward now.

But in future when drilling something like this put a piece of 9.5/12.5 mm plywood under it held in place with a c clamp. Should stop the knockouts from falling out
 
For me make a new plate and pre drill this so fits nicely over balls up and your glans holds it all together !
 
Yep, plate it (and maybe put some high temp sealant around it).

Won't help here but the newer Contactum boards have 32mm knockouts on both sides (top right side and top left side) and also on the bottom right and top right. Not a recommendation as I don't like the fit of the front, but for future ref.
 
You could get your grinder and cut a slot out of the top of the CU and stick a bit of 3 or 4 inch trunking on top of that depending if you have many cables coming into it
 
Englishman said:
Not any help now, but you could possibly drill a smaller hole and then open it up with one of those cone cutter things, designed to open metal holes up.
Click to expand...

Not a bad idea at all. I wander whether the knock out would still hold firm though. Malcolm's idea should allow for the hole to be drilled neatly. Silly design by the manufacturers, they should have a couple of different options for the actual enclosure. Maybe they should do a bit of market research, asking sparks their views..
 
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I have had this occur,when knock-outs displace,or errors,retro-fit etc,necessitates a change of position or aperture size.

Usually,it is best to fit as large a piece of material as is possible,which matches the original cabinet. This can make any "special" shapes or slots,easier to machine,as it can be vice-work.

A few years back,i had cause to strip out several phone mast control cabins,which possessed a myriad of enclosures,cabinets and racking.

The stores area had a large pile of packaged,stainless blanks,epoxy coated on one side,and in varying size,from 50mm square,to 100 mm x 500 mm.

These have proved invaluable for such tasks,fixed suitably to maintain continuity.

When drilling around such knock-outs,you have to be ready for when they fall out...with only a "knock" :stooge_moe:
 
davesparks said:
Apart from being made by silverline and sold by CEF it looks lovely ;)
Click to expand...

Yes I know! :angry: BUT it shows that they are available up to & beyond 32mm ....... I thought the biggest was 22mm.

That said, it's not something that you use all day everyday so for the occasional use it could ok PROVIDED you keep the speed (RPMs) down & use plenty of lubricant.


And there's always this:
ShowImage.ashx
 
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Geordie Spark said:
Yes I know! :angry: BUT it shows that they are available up to & beyond 32mm ....... I thought the biggest was 22mm.

That said, it's not something that you use all day everyday so for the occasional use it could ok PROVIDED you keep the speed (RPMs) down & use plenty of lubricant.


And there's always this:
ShowImage.ashx
Click to expand...


Ohhhhhhh now we are talking. Great for making holes in stainless
 
I don't think you should be drilling the knock-out smaller than its intended diameter in the first place, you should either remove it entirely or not use it at all. Problem is if you drill it and fit an SWA gland there's a good chance it's going to break free anyway at some time in the future. The CU manufacturers should stop catering to DIY'ers and fit a proper gland plate that doesn't have pre-perforated knock-outs or leave the side and back walls without knock-outs assuming they're strong enough to take SWA glands without distorting.
 
Marvo said:
I don't think you should be drilling the knock-out smaller than its intended diameter in the first place, you should either remove it entirely or not use it at all. Problem is if you drill it and fit an SWA gland there's a good chance it's going to break free anyway at some time in the future. The CU manufacturers should stop catering to DIY'ers and fit a proper gland plate that doesn't have pre-perforated knock-outs or leave the side and back walls without knock-outs assuming they're strong enough to take SWA glands without distorting.
Click to expand...

Problem is Marvo that there are countless existing installations where changing the CU is made difficult by all the DIY changes and hence why, I suspect, they have these large knock outs - quite how they expect the installer to maintain the IP rating and the "non combustibility" is questionable.
 
I have not yet fitted a metal domestic board yet, and have to say I am not looking forward to it, I can see them just being awkward and problematic.
 
Geordie Spark said:
This could be useful:https://www.cef.co.uk/catalogue/products/1039967-20-36mm-titanium-coated-step-drill
Click to expand...

i only ever use a cone / step drill when drilling a hole in metal as I know I can control it quite well, I would recommend using one certainly, may not be the quickest method, but they don't skid about and you feel a bit safer / more confident about know its not too big, you can check the size as you go. Plus it gives you time to think about what size you are going to whilst its drilling.
 
uksparks said:
I have not yet fitted a metal domestic board yet, and have to say I am not looking forward to it, I can see them just being awkward and problematic.
Click to expand...

Thought that before I started fitting them but they're actually a lot nicer to fit than the old insulated ones. Take a bit longer getting it on the wall and fireproof etc but it looks better and is so much nicer to work with.
 
Geordie Spark said:
Yes I know! :angry: BUT it shows that they are available up to & beyond 32mm ....... I thought the biggest was 22mm.

That said, it's not something that you use all day everyday so for the occasional use it could ok PROVIDED you keep the speed (RPMs) down & use plenty of lubricant.


And there's always this:
ShowImage.ashx
Click to expand...
you can get 51mm step cutters now.

i only had to drill two holes but the ****e stocked by cef struggled.

dart holesaws are awful, ive got one of there arbors that is only any use without a pilot bit XD
 
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TheGayOwl said:
Not a bad idea at all. I wander whether the knock out would still hold firm though. Malcolm's idea should allow for the hole to be drilled neatly. Silly design by the manufacturers, they should have a couple of different options for the actual enclosure. Maybe they should do a bit of market research, asking sparks their views..
Click to expand...

I emailed Hager about this exact problem over 6 months ago. Never heard anything back. I too had to drill out the board and there's little tolerance/ room for error. The old metal hager boards with the plastic fronts had 20 and 25mm round knockouts. Personally if I need to secure SWA now I'll choose another make of board instead.
 
richy3333 said:
I emailed Hager about this exact problem over 6 months ago. Never heard anything back. I too had to drill out the board and there's little tolerance/ room for error. The old metal hager boards with the plastic fronts had 20 and 25mm round knockouts. Personally if I need to secure SWA now I'll choose another make of board instead.
Click to expand...

I was doing a 5 way "garage" type install last week - so went into a wholesaler and asked to see the metal box and looked at the knock outs before I parted with my money! I used the Wylex unit - 3 x 20mm knockouts and I needed 3!
 

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32mm Holesaw in Metal Consumer Unit knock out - balls up!
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