Installing Steel Conduit

[BS3036]

Let's suppose you need to install a Ring Final in steel conduit. This would seem to involve a ring of steel conduit in which you might fit each piece of conduit by screwing it into the previous piece. The last piece would seem to need to be screwed into two female threads and unless one of them was a left hand thread it would not seem possible. Is the answer that you can't install a ring final in steel conduit?

 

[sparkymarka]

Errrr no ……you have 2 steel conduits going into the consumer unit …

 

[Robin0577]

Only the wiring of a ring final circuit has to be a ring, the physical layout can be anything you like. The return leg of the ring could easily go back up the same conduit for instance.

 

[plugwash]

Is the answer that you can't install a ring final in steel conduit?

No.

First off, generally not every item in a conduit system is a box with a pre-attatched threaded conduit entry, some items will be boxes with plain holes where the conduit is terminated using a bush and coupler. The couplers can be attached to the conduit system first and then the bushes can be screwed in afterwards.

Secondly if you do need to join two lengths of conduit without rotating them, there is a technique known as a "running coupler", you cut a long thread on one of the conduits and a regular length thread on the other. You then thread a locknut and coupler onto the long thread. The coupler can then be partially unthreaded from the long thread and onto the short thread of the other conduit. Finally the locknut can be tightened against the coupler to lock everything in place.

demonstrates the technique.

 

[Harry Bloomfield]

Let's suppose you need to install a Ring Final in steel conduit. This would seem to involve a ring of steel conduit in which you might fit each piece of conduit by screwing it into the previous piece. The last piece would seem to need to be screwed into two female threads and unless one of them was a left hand thread it would not seem possible. Is the answer that you can't install a ring final in steel conduit?

A ring circuit can be an elongated linear ring, both legs going out/returning from the same point. Where two separate bit of fixed conduit need to be joined, then the way to do it is to have a normal thread, or a threaded nipple in a box, and an overlong thread on the other conduit and use a coupling and a lock nut. The thread faces are put in close alinement, the coupling is run along the long thread and the short thread until tight, then the locknut tightened behind it.

 

[333rocky333]

However if you did want to make a Ring of steel conduit, you would do what is known as a "RUNNER, it consists of a long thread, a male coupler and a lockring.
Basically the coupler is on one pieces thread with the locknut, you wind the coupler onto the other peices thread, then lock it up with the locknut.

Never noticed Harrys post or plugwash

 

[Risteard]

Don't forget you need to paint the exposed thread of any running couplers.

 

[BS3036]

Thanks for all the answers. I'll review them with interest.