Can you fit 25mm conduit to a 20mm back box?

[laurence1995]

Hello,

Im really new to the world of conduit. I have some 25mm pvc conduit and cant for the life of me seem to fit back boxes with 25mm knockouts. Is there an adapter that fits a 25mm conduit in to a 20mm back box? Can i cut a 25mm hole in the back box? Do the 20mm male adapters allow for 25mm conduit to go into 20mm back boxes?

 

[IAmSparkytus!]

I have bought Q-max punches before from both of these places:

Q Max Sheet Metal Hole Punch Metric | Hole Punches

Buy Q Max Sheet Metal Hole Punch Metric and other Q Max Hole Punches at Tooled-Up.com. Fast Delivery.

www.tooled-up.com

Toolbank Express — Toolbank Marketing

www.toolbank.com

However there are other places you might find them, not always as good value or in-stock:

https://uk.farnell.com/ruko/109200/punch-hole-round-20mm/dp/4700806

Q-MAX Cutter Round - Metric

Q-MAX Cutter Round - MetricQ-Max Cutter for manually punching holes in sheet steel up to 1.6mm and aluminium up to 2.0mm. Very simple 100% British made tool that has been in production for over 50 years. To use, you simp

stakesys.co.uk

Just had a quick look at these, they look good. Have you seen the Milwaukee power tool which does the same thing? Very impressive but very expensive at the same time for what it does. The Q Max cutter looks a great alternative. It says to use and Allen key or spanner/socket set to tighten up but do you know if a socket attachment for an impact driver would work to make it quicker?

 

[laurence1995]

View attachment 105823has anyone ever used these?

So i can put my 25mm conduit into this have a very small 20mm out the other side and then a female and male adapter to connect to the 20mm back box! Probably i very long way to do it but it should still work. Does that make sense? Ha

 

[DPG]

So i can put my 25mm conduit into this have a very small 20mm out the other side and then a female and male adapter to connect to the 20mm back box! Probably i very long way to do it but it should still work. Does that make sense? Ha

Will your cables fit through it though?

 

[davesparks]

So i can put my 25mm conduit into this have a very small 20mm out the other side and then a female and male adapter to connect to the 20mm back box! Probably i very long way to do it but it should still work. Does that make sense? Ha

Yes you could do that, but it will be an ugly mess, hopefully this isn't for a customer!

If the cables can fit through a 20mm hole why are you using 25mm conduit?

And if a 25mm conduit is required for number/size of cables then drill the 20mm hole out bigger with a cone cutter/step drill.

 

[laurence1995]

Yes you could do that, but it will be an ugly mess, hopefully this isn't for a customer!

If the cables can fit through a 20mm hole why are you using 25mm conduit?

And if a 25mm conduit is required for number/size of cables then drill the 20mm hole out bigger with a cone cutter/step drill.

Ok thank you, its not for a customer, its for me i like the idea of making the whole bigger

 

[ipf]

Ok thank you, its not for a customer, its for me i like the idea of making the whole bigger

Making a hole a whole lot bigger always does the trick....or as the Spanish say......
....'Oe'.

Whether the box is soft plastic or metal, a metal cone cutter should do the job, as long as you have the box depth.

 

[laurence1995]

One the hole has been made, qould you recommend a male or a female connector?

 

[ipf]

One the hole has been made, qould you recommend a male or a female connector?

Generally, female conduit coupler to male bush is better, leaving more room inside the box, but it depends on the situation.