Bending 20mm galv conduit

[Knobhead]

Sorry I’m lost here, why would you need a lock ring with a coupling, if the conduit is the correct length there’s no need.
I’ve never used a serrated washer with conduit either.

 

[Engineer54]

Never seen lock rings used on any installation anywhere, apart from running joints!! Like Tony i can't see the point of locking a coupling connection??

 

[johnboy6083]

i use lockrings with couplers if im bushing into trunking ect, and i have no flanged couplers, but i dont use lockrings on any coupler, unless its a running coupler. Dont use serrated washers on anything other than cables glanded onto heavily vibrating equipment.

 

[Dcf]

You can tell if the firm doing the work were scottish or english Coupling,lockringed = scottish no lockring = english serated washers= scottish no serated washers= english

It's the way it's always been done in scotch land.
i used to like the flanged couplers as they used to tighten up really well,don't see them that often now tho it takes suppliers all ther time to get you a 20mm y box these days so no surprise there.
i used to use a bending block quite often as my old gaffer had one hilmor bender between 15 boys.what he didn't realise is that 20mm Galv is a bit tougher than 3/4 black enamel,still do able but a bit more effort.if the op has just one set I would go down the block route .my hilmor gets an airing about twice a year on average but it will see me out til retirement.ill get the bairns to put it on the antiques roadshow.......wtf is that!?

 

[madmac]

The reason why Lockrings are used at every coupling is to make them as tight as possible for a good electrical and mechanical connection, especially when conduit is hovering from screwed rod etc. The reason why serrated washers (jaggy washers) are used is for a similar reason, they give an extremely good electrical connection, especially for metal clad boxes. The thinking is that the conduit is still classed as an earthing conductor if required and to keep good practice going, even if the modern standards are slipping!

 

[oldtimer]

Yep o-rings are to make sure of the conduit being "Electrically & Mechanically Sound" (14th edition) and god did I bend and screw some conduit and I am pleased to say not for the past 30 years and do I miss it no chance

 

[sedgy34]

if you have an apprentice and arms like popeye bend your set round his head (job done)

 

[Dcf]

Used to work with a guy whos party trick was to bend it round his neck.he was a total beast of a man who's neck was probably about 22"!minimum bend radii assured.

 

[Knobhead]

Yep o-rings are to make sure of the conduit being "Electrically & Mechanically Sound" (14th edition) and god did I bend and screw some conduit and I am pleased to say not for the past 30 years and do I miss it no chance

If the coupling is screwed firmly to the root of the thread you will not get a tighter or more electrically sound connection. As for serrated washers, if you have bright metal to bright metal, how do you better that?
When connecting conduit in to trunking I used to deliberately leave the bur so it dug in to the coupling or bush.

 

[Engineer54]

Can't say we've ever had any problems with our conduit systems, and we test all the runs with a 25A ductor tester. We don't suspend conduits from long screwed studding either, that can be asking for trouble and looks pants too. We do however use serrated lock rings in certain circumstances at panels and accessories etc!!

 

[madmac]

It is over the top granted, I'll give you all that but I'd rather we went over the top and did left a top notch job that carried on good practice from previous regs as oldboy says.
And Tony..."If the coupling is screwed firmly to the root of the thread you will not get a tighter or more electrically sound connection." yes you will get a more tighter connection by using a lockring either side of a coupling, it's the same principle as locking two nuts together to turn a thread etc.
Also bright metal to bright metal you are correct but I was talking about metal clad (painted boxes).
And as for leaving burrs on trunking!!! That's the first bad practice to be knocked out of an apprentices head!! and not very proffesional at all! just use a serrated washer, end of.
I'm glad you don't suspend from long screwed rod Engineer54 but not all jobs have the alternative luxury to do a better install.
But I do like the idea of testing conduit with a ductor tester, never seen that before, again possibly down to time/cost factor but then again when installed with lockrings and serrated washers............

 

[Knobhead]

Not many would have access to a Ductor now a days. It's what I always used.

 

[Engineer54]

But I do like the idea of testing conduit with a ductor tester, never seen that before, again possibly down to time/cost factor but then again when installed with lockrings and serrated washers............

Just used to be called conduit testers in the old days. Clare tester as they used to be called!! There not ''True'' ductor testers as such, just an ohm meter that measures through a high current (25A)!! Basically it's the only way you can really test/prove a metallic conduit/trunking containment system is solidly connected throughout!! Any loose or bad metal to metal connections would soon be found by that injected 25A...lol!!

All the bigger electrical contractors would carry such test equipment, and yes your right, they are on the expensive side!! lol!! But then most small companies and electrical sole traders wouldn't be undertaking such extensive metal containment systems, to warrant the cost of these test kits.