Threading 1-1/4" RMC

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jeff48356

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Livonia, Michigan
I just got an upcoming job where I will need to rewire an old house and install new service. I'm going to use a metal riser for overhead 100A service, and I will need more than 10 feet of pipe. For the second piece, how would I thread it so that it fits into the meter hub?
 
Are you saying you will use 1.25" for a service mast? In any case, IMO, you need to have a threaders up to 2". I always had a tri stand (pipe vice), cutting oil, and hand threader on the truck. That was early in my career, later a porta pony took the place of the hand threader.

Roger
 
jeff48356 said:
OK, I didn't know a plumbing shop would thread electrical conduit.
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No difference. RGS is the same as galvanized plumbing pipe though only RGS is listed for electrical use. So anybody or anything that you use to thread plumbing pipe can be used to thread RGS.

I have recommended Home Depot, Lowes, local hardware stores. In those cases though bring them only straight lengths because they chuck it in a power head. Otherwise if it's already bent you can't spin it so you will then have to thread it by hand or with a porta pony.

-Hal
 
I've got a 65R. It threads 1" - 2" Bought it maybe 20 years ago used. Put new dies in it when I bought it.
And you will need tripod pipe vise.

I suspect ebay will have a bunch.
 
jeff48356 said:
I just got an upcoming job where I will need to rewire an old house and install new service. I'm going to use a metal riser for overhead 100A service, and I will need more than 10 feet of pipe. For the second piece, how would I thread it so that it fits into the meter hub?
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A credit to OP to ask , everyone has to learn the basics sometime in their life.


However, some questions like this make one wonder about a description of "I'm a licensed master electrician and electrical contractor".

Many, maybe not every electrician, but every electrical or building contractor I know has a set of pipe dies up to 2"; however, very few residential contractors have stuff over 2". Most contractors will even have a motorized threading machine for up to 2".

Even many of us dumb engineers who just dabble in residential for habitat, friends, and relatives have pipe threading equipment.

Not trying to be personally critical or nasty, but do have to wonder how OP ever passed master test without knowing how to thread rigid conduit?

A quick look at ebay showed die sets up to 1-1/4" for $50 including shipping!
Hint for OP - always use plenty of cutting oil.
 
junkhound said:
A credit to OP to ask , everyone has to learn the basics sometime in their life.


However, some questions like this make one wonder about a description of "I'm a licensed master electrician and electrical contractor".

Many, maybe not every electrician, but every electrical or building contractor I know has a set of pipe dies up to 2"; however, very few residential contractors have stuff over 2". Most contractors will even have a motorized threading machine for up to 2".

Even many of us dumb engineers who just dabble in residential for habitat, friends, and relatives have pipe threading equipment.

Not trying to be personally critical or nasty, but do have to wonder how OP ever passed master test without knowing how to thread rigid conduit?

A quick look at ebay showed die sets up to 1-1/4" for $50 including shipping!
Hint for OP - always use plenty of cutting oil.
Click to expand...


I have been a self employed electrician for 10 years and doing my own side jobs for 5 years before that. I do not have threading equipment. I have needed to thread remarkably few times. Also it is not as easy at it might seem to get a piece of pipe threaded. One time I need a piece of 2" threaded for the same situation as the OP. Big orange wouldnt do it, said electrical conduit messed up their dies (BS but what can you do). Other options are:

1. Put the cut piece at the top where you dont need threads (although often puts the coupling in a prohibited spot).
2. Use nipples. Probably only available up to 12" though and starts to look hack joining several together.
3. Use impression connector into the hub or a compression coupling. Note most are not raintight and the raintight ones can be hard to find.
4. Transition to EMT (kinda hack).
 
electrofelon said:
I have been a self employed electrician for 10 years and doing my own side jobs for 5 years before that. I do not have threading equipment. I have needed to thread remarkably few times. Also it is not as easy at it might seem to get a piece of pipe threaded. One time I need a piece of 2" threaded for the same situation as the OP. Big orange wouldnt do it, said electrical conduit messed up their dies (BS but what can you do). Other options are:

1. Put the cut piece at the top where you dont need threads (although often puts the coupling in a prohibited spot).
2. Use nipples. Probably only available up to 12" though and starts to look hack joining several together.
3. Use impression connector into the hub or a compression coupling. Note most are not raintight and the raintight ones can be hard to find.
4. Transition to EMT (kinda hack).
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5. use pvc. Only time we ever use rigid is for a mast service and that would be 2"
 
For one thread you could just run over to the Home Depot plumbing department or any other local place with a NPT threader. I would say use a threadless on the hub end at the meter but that wouldn't be code compliant due to the straight threads.
 
junkhound said:
However, some questions like this make one wonder about a description of "I'm a licensed master electrician and electrical contractor".

Not trying to be personally critical or nasty, but do have to wonder how OP ever passed master test without knowing how to thread rigid conduit?
Click to expand...

I started out in industrial so I'm very familiar with threading rigid conduit but many electricians in this area have never worked in industrial because there isn't much industrial work. You could easily get the hours needed to take the test without ever touching rigid conduit in commercial work.

When you take the test to become a contractor there may be a couple of questions about pipe threads but that's about it.
 
hbiss said:
No difference. RGS is the same as galvanized plumbing pipe though only RGS is listed for electrical use. So anybody or anything that you use to thread plumbing pipe can be used to thread RGS.
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Yes, some differences in what is required for listing purposes, but pipe itself is same external dimension and same NPT thread pitch is used.
 
Since we are discussing basics, another tidbit for OP.

If one looks at water pipe vs RMC, the water pipe weld seam will be able to be felt with your finger, not so on RMC.

Was taught that years ago as to why never to try to substitute water pipe even in a pinch, the weld seam is know to be able cut thru insulation as wire is pulled, even in straight sections.
 
Out where I am there are supply houses that will cut and thread (and even bend) rigid. Maybe check with your supply houses to see if they thread?
 
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