Fitting uPVC cable conduit connector

[Iain741]

Hi guys...just needing a bit of a sanity check here. I bought 20mm plastic conduit and 20mm T boxes & elbows. Should those fit together??? I'm trying to get the conduit inside the connector, they both seem like exactly the same size! Photo attached.

Am I doing something wrong? How do I join those?

Cheers

 

[Murdochcat]

Are you sure that’s 20mm conduit ?

 

[plugwash]

Hi guys...just needing a bit of a sanity check here. I bought 20mm plastic conduit and 20mm T boxes & elbows. Should those fit together???

Yes.

I'm trying to get the conduit inside the connector, they both seem like exactly the same size!

My best guess is the supplier sent 25mm conduit by mistake. Can you measure it?

 

[flameport]

That 'conduit' is more likely to be black PVC overflow pipe, which is a few mm larger than conduit.

 

[SUNRAY]

In my experience; internal diameter of 25mm conduit is likely to be around 20 to 22mm, by assumption the external diameter of a 20mm socket is likely to be a minimum of 22 up to 25mm.

That looks like 25mm conduit to me.

That 'conduit' is more likely to be black PVC overflow pipe, which is a few mm larger than conduit.

The overflow I've used is 3/4" or 22mm, I believe that image shows something bigger than 22mm.

 

[EFLImpudence]

3/4" is 19mm.

 

[Iain741]

Mate, you're exactly right...I went to take a quick photo of the conduit and noticed it's 25mm Must have been a long day, that's all i can say about that!!!!

Cheers for the help all

 

[SUNRAY]

3/4" is 19mm.

yes

 

[plugwash]

3/4" is 19mm.

It is.

However, sizing of pipes/tubes is a mess. Some are measured by their outer diameter, some are measured by their inner diameter, and some are sold based on a "nominal inner diameter" which represents the inner diameter of a historical pipe that had the same outer diameter as the pipe being sold. It's not a hard and fast rule, but imperial measurements are more often associated with inner diameters, while metric measurements are more often associated with outer diameters.

 

[SUNRAY]

The overflow I've used is 3/4" or 22mm, I believe that image shows something bigger than 22mm.

Confused ?
I'm referring to older imperial overflow pipe which was 3/4" OD (and incidently made excelent couplers for 16mm plastic conduit) and 22mm overflow pipe, 2 different products different in size by 3mm.

 

[ebee]

Plumbers and joiners tend to stick to inches (feet and yards too) and electricians and engineers tend to stick to millimetres and metres.
Conversions in size are very approximate and therefore not always accurate and it is often helped, a bit, by using alternatives of inside diameters and outside diameters to get a nearer match.
It all helps with the confusion.
And Electricians tend to use lots of Greek Symbols so they can charge more on their invoices.
You needs to go Metric every Inch of the way!

Long live the "Metric 13" my local woodyard foreman used to refer to them as meaning a 4 metre stick of 3 x 2 being about 13 feet (he was a couple of years older than me at school)

Remember Covid and the distance rule? We adopted the 2 metre rule, which is about 6ft 7inches so most folk rounded it down to 6 foot then miss calculated it as 5 foot or 4 foot too.

 

[Risteard]

Plumbers and joiners tend to stick to inches (feet and yards too) and electricians and engineers tend to stick to millimetres and metres.
Conversions in size are very approximate and therefore not always accurate and it is often helped, a bit, by using alternatives of inside diameters and outside diameters to get a nearer match.
It all helps with the confusion.
And Electricians tend to use lots of Greek Symbols so they can charge more on their invoices.
You needs to go Metric every Inch of the way!

Long live the "Metric 13" my local woodyard foreman used to refer to them as meaning a 4 metre stick of 3 x 2 being about 13 feet (he was a couple of years older than me at school)

Remember Covid and the distance rule? We adopted the 2 metre rule, which is about 6ft 7inches so most folk rounded it down to 6 foot then miss calculated it as 5 foot or 4 foot too.

I adopted the hug a stranger rule.

 

[Adam_151]

We have a strange hybrid of imperial and metric systems....

Pipes for water are metric sized these days, but threaded BSP threads in imperial sizes are used

Pipes for air conditioning and refrigertion are imperial sized

if you buy a sheet of plywood its 2440x1220 as thats 8x4 in old money, but if you go and buy a sheet of plasterboard, its been rounded down to 1200 x 2400

I can buy No.8 by inch and half screws from one supplier, but at another I have to look for ones labeled 4x40mm

Some MEM busbar chambers out there have a label requiring you to maintain 19mm clearance between lugs on other bars and earth, which is oddly specific until you remember that 19mm is 3/4" - I would have just rounded it up to 20mm!

We changed the screws on BESA boxes to M4, but the fixings still remain at 2" centres (Yes changing this would have been convienient, but so was changing conduit sizes!)

No one talks about 100mm and 150mm tray and trunking even if thats what it is on the wholsalers system, its always ordered as 4" and 6"

 

[ebee]

That`s mostly correct Adam, 19mm is a tadd under 3/4 inches that's one example of the rounding or the "Metric 13" comes in.
I have 25.40mm to 1 inch and 1mm is .039370078 inches stuck in my brain because I got it hammered into me as an apprentice straight from school for 4 years then as a skilled craftsman with additional "Technician Qualifications" it carried on with those around me for a few years of my working life. I then became a self employed electrician (mostly domestic) and specialised in intruder alarm systems (again mostly domestics but a good mix of shops, offices and factories too) and I worked very much alongside/for/ or subcontracted other trades such as plumbing/heating emgineers, joiners and various others in the building trade and became aware of their trends towards the old imperial system, I sometimes offered to pay them in farthings and groats but it did not impress them. I even had an annoying habit of speaking in Pounds Shillings and pence (d) instead of Pounds and (new) pence but that still did not impress them in the 80s and 90s .

In fact one odd fellow that never got let out on site used to come up with daft statements like "It is not half a metre it is point 5 of a metre or half a yard" so I deliberately mixed decimals, fractions and ratios during my conversations with him (his heart was always in the right place bless him and that`s why none of the other lads ever strangled him to death even though they really wanted to at times ).

 

[EFLImpudence]

A tadd is one twentieth of a millimetre. Do they make sockets and spanners that accurately.

Actually if a nut and a socket were both exactly 19mm. they wouldn't fit together easily so which one is larger or smaller than stated?