# 2.5 " rigid steel mast - extend??



## SlimV (Jan 19, 2010)

I am installing the mast for my house and have run into a bit of a problem. The mast will project thorugh the roof so it must be rigid steel. However, the longest length of pipe I can find is 12'. I need at least 13' preferablly 13'6" as it must be 36" cap must be 26" above roof. 

I have been told that I can use a coupler and extend the mast in the section nearest the meter base. 

I do not know what type of coupler to use and I have asked my local electrical supplier and they are unsure as well. 
Do you thread the pipe and use a threade collar?

Any help would be greatly appreciated.


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## woodchuck2 (Feb 27, 2008)

If the mast is not threaded on one end then take it to a local hardware or plumbing place to have it threaded "NPT" and just use a standard steel coupling. Wouldnt hurt to use some pipe dope on the threads to help with water intrusion. The section you add to it obviously needs to be threaded on both ends so it may thread into the coupling and meter hub. Again use of pipe dope on those threads would be beneficial too.


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## bhock (Feb 17, 2009)

It surprises me that the electrical supplier didn't know!
Unless the electrical supplier was a pimple faced kid at Homeless Repo.


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## Anti-wingnut (Mar 12, 2009)

woodchuck2 said:


> If the mast is not threaded on one end then take it to a local hardware or plumbing place to have it threaded "NPT" and just use a standard steel coupling


You make it sound like he can uae any off the rack coupler. Most electrical suppliers sell threaded couplers for 2 1/2" rigid conduit . Tis way you will retain the UL rating on all your parts


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## 480sparky (Feb 1, 2009)

Rigid conduit comes with a coupler. Use that one.:thumbsup:


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## Kgmz (Feb 9, 2007)

Go to a different supplier, and hopefully a wholesale supplier. Also can;t believe a real supplier doesn't know anything.

And like 480 said, when you buy a length of rigid it comes with one coupling. I would not use a plumbing coupling and don't how the inspectors are up north, but around here you better not use one. A electrical coupling has straight threads while plumbing coupling will have tapered threads.


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## SlimV (Jan 19, 2010)

*Supplier*

Ya the supplier was a reputable commercial electrical supplier and the guy seemed to know jack. Will try another one today... or same place different guy:laughing:.

The conduit I bought didnt come with a coupler and is not threaded either end. Will see if they have a different kit that comes with one coupler


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## woodchuck2 (Feb 27, 2008)

My bad for the mis-leading info i 1st posted, you fella's are correct on the thread taper and coupling. I believe masts' and coupling are also galvonized or at least have a anti-corrosion surface where as normal plumbing pieces do not. I have found that some plumbers or even a good hardware store have the dies for threading the pipe, but no one in this area carries the parts such as the proper coupling. Around here you can buy the mast as one length threaded on both ends/capped, beyond that your on your own. For us it is a 40 mile one way drive to find a supplier who handles a coupling. As foolish as it sounds i save all the masts i take down just for parts, i have also gone to the local Ski Resort that i used to work at and begged them for parts to save me the drive.


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## Anti-wingnut (Mar 12, 2009)

If it is actually 2 1/2" OD, it is not possible to thread it using pipe dies, nor is it possible to buy threaded fittings.

The OD for 2" rigid conduit and 2" pipe is 2 3/8". The OD for nominal sized 2 1/2" pipe and conduit is 2 7/8". When you say your mast is 2.5", is this mis-measured 2" pipe or is it actually 2.5" OD?

You will find it difficult to get pipe larger than nominal 2" threaded. The most common pipe machines (Ridgid 300 and 535) thread to 2". Some machines thread to 4" ( and to 24"), but these are uncommon in the field, hardware store, or speciality supplier. Most pipefitters use a separate geared threader to thread 2 1/2" to 4" pipe. Most electricians ask the fitters, buy pre-threaded fittings, or use 2".


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## aptpupil (Jun 12, 2010)

don't forget to strap it down before and after the coupling which is a weak point in the mast.


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