underground rigid

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blue302

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What kind of rigid couplings are approved for direct burial,or does it need to be threaded on both ends.I usually use pvc for underground but in this instance I need to use rigid.It's 3 inch.I don't have a threader and it's a short run.Thanks
 
blue302 said:
What kind of rigid couplings are approved for direct burial,or does it need to be threaded on both ends.
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If you are asking , ''What couplings are approved? '', your AHJ can give that answer.

To my knowledge there is no rule restricting the use of compression fittings underground.

Ibew441dc
 
...from American Fittings

Rigid-IMC Couplings
Compression Type - (No Thread)
Industrial specification grade, screw machined steel, zinc plated
UL Listed Rain Tight and Concrete Tight 1/2? ? 2?
UL Listed Concrete Tight 2-1/2? ? 4?


I don't think they can be used underground without concrete encasement.
 
How much for fittings and how much for threader rental? You may find that renting a threader is actually a better price compared to multiple compression fittings anyway. And if it gives you peace of mind all the better.
 
tmbrk said:
How much for fittings and how much for threader rental?
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For the 3" he's talking about, you'd need a hog-head threader. I'm not even sure if rental places have those. I have 3, and they're gathering dust. Go figure.
 
2005 NEC?, Article 100 defines a wet location as follows:

Wet Location. Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as vehicle washing areas, and locations exposed to weather and unprotected.

No raceway system is really "watertight", including those that are glued or have sealed joints. Normally raceways will collect condensation. The raceway is designed to allow this moisture to drain out. It is understandable that in some cases where the ground does not percolate well, the water will also seep in. This is why the conductors installed must be of a type approved for wet locations i.e. THWN or XHHW.

The 2005 NEC? permits EMT, IMC and RMC to be installed in all wet locations both inside and outside. NEC? 300.6(C) requires all metallic raceways installed indoors in a wet location to be mounted so there is at least a 1/4" inch air space between the raceway and the supporting surface to minimize the accumulation of moisture. NEC? Sectons 342 (345).10(D), 344 (346).10(D) and 358 (348).10(C) caution the installer that all hardware items such as straps, bolts, screws etc. be of a corrosion resistant material when used to support raceways in wet locations. When threadless fittings are used with RMC and IMC, they must be identified and listed for the application. Threadless fittings intended for use in wet locations are marked "Raintight" or "Wet locations" on the fitting or its smallest unit shipping container. Threadless fittings intended for embedment in poured concrete are marked "Concrete-tight" or "Concrete-tight when taped" or "Raintight" on the fittings' smallest unit shipping container. Fittings listed as "raintight" are also "Concrete-tight", but not all concrete-tight fittings are raintight.

courtesy of the "Steel Conduit Website" at http://www.steelconduit.org/basic.htm
 
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Power threaders for up to 4" pipe rent for around $60 - $75 a day around here.

Of course you have to go get it and return it, but it fits in the back of a small pickup.
 
hardworkingstiff said:
I have one, and use it rarely. How in the world did you wind up with 3?
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Big RMC job, high profit, warrented getting 3. Darned shame to see them sitting. I've got a 40' trailer load of equipment that was only used on that one big job. I'm a small operator. I'm too depressed about the fact to sell the stuff. "I might need it one day", I tell myself.
 
mdshunk said:
Big RMC job, high profit, warrented getting 3. Darned shame to see them sitting. I've got a 40' trailer load of equipment that was only used on that one big job. I'm a small operator. I'm too depressed about the fact to sell the stuff. "I might need it one day", I tell myself.
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Sounds like you're ready for another big RMC, high profit job. :D :grin:
 
Sell it, and invest the money in an IPO. Preferably from a large cellular telephone service that has wireless laptop service in most large metropolitan areas. I just read a press release on this one. Remember Google?
 
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