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-   -   conduit and fittings (http://www.diychatroom.com/f18/conduit-fittings-20670/)

analogmusicman 05-05-2008 11:54 PM

conduit and fittings
 
while at Lowes I thought I'd check out their electrical stuff for my upcoming project of running about 100' of conduit and wires for a range. there is evidently a HUGE difference in the price of conduit between regular EMT and what is known as RIGID conduit. Lowes only carries RIGID and it's $16 for a 10' length of 3/4 vs $4.50 at HD for a 10' length of EMT!
where would you use that tougher RIGID stuff? I'll bet it's not easy to cut or bend! (it's galvanized steel)
as far as fittings go, the prices at Lowes seem to be high, I'm going to check the prices at a regular electrical supply place tomorrow.
no wonder getting electrical work done is so expensive, that and the price of gas will definitely put a dent in your paycheck! :no:

HouseHelper 05-06-2008 05:31 AM

Look around some more at the lowes. They carry EMT at virtually the same price as HD.

Silk 05-06-2008 05:46 AM

You don't need Rigid, EMT will work just fine for you. If you use Rigid then you will also need a threader, it's not work it.

BigJimmy 05-06-2008 07:38 AM

Listen to Silk. I wouldn't go near ridgid pipe unless I had to. In addition to that threader he mentioned, you also need something to cut that pipe very cleanly and straight. Then you need to ream the ends. And if you overthread? Bending anything over 1/2" is no picnic either.

Termite 05-06-2008 07:59 AM

My question is why on earth are you running conduit to a range?????

BigJimmy 05-06-2008 08:34 AM

Quote:

Originally Posted by analogmusicman (Post 121248)
where would you use that tougher RIGID stuff?

It's primarily used in industrial and some commercial construction where mechanical damage is a concern. I've never seen it used inside a residential dwelling, only for exterior uses such as for services.

It is truly amazing to watch a journeyman run a rack of 3" RGS pipes and have all the kicks, offsets, 90's all line up perfectly. The fact that the entire conduit system is threaded requires even more skill and planning on the part of the electrician to actually install the stuff (yeah, I know, you DO find Erickson's on occasion).

jrclen 05-06-2008 10:27 AM

We use rigid metal conduit for locations that are hazardous, like gas station islands, or subject to severe damage like ally ways where it could be hit by cars and trucks. In industrial plants. It is also used underground. And in wet or corrosive locations. It is threaded, so any cuts must be re-threaded, and the thread takes a special die, which is straight thread and not tapered like plumbing pipe threads. It is harder to bend than thin wall. It comes in many materials, galvanized steel, stainless steel, brass, and aluminum.

No need to use it for your range.

analogmusicman 05-06-2008 05:32 PM

Quote:

Originally Posted by thekctermite (Post 121279)
My question is why on earth are you running conduit to a range?????


well,"kc" the conduit has to run outside the house.

NO,I'm definitely NOT even thinking of using the RIGID stuff! was just curious...

tnx,

Cow 05-06-2008 06:37 PM

Quote:

Originally Posted by jrclen (Post 121297)
It is threaded, so any cuts must be re-threaded, and the thread takes a special die, which is straight thread and not tapered like plumbing pipe threads.

I disagree, rigid is threaded using standard tapered pipe dies. The fittings are typically straight threaded.

jrclen 05-06-2008 08:02 PM

Quote:

Originally Posted by Cow (Post 121374)
I disagree, rigid is threaded using standard tapered pipe dies. The fittings are typically straight threaded.

Ooops. My mistake, you are correct.

Termite 05-06-2008 09:45 PM

Quote:

Originally Posted by analogmusicman (Post 121366)
well,"kc" the conduit has to run outside the house.

NO,I'm definitely NOT even thinking of using the RIGID stuff! was just curious...

tnx,

Gotcha. Didn't see that coming.

Be sure you use weathertight fittings on your EMT. Regular fittings won't work outdoors.

analogmusicman 05-06-2008 09:50 PM

Quote:

Originally Posted by thekctermite (Post 121420)
Gotcha. Didn't see that coming.

Be sure you use weathertight fittings on your EMT. Regular fittings won't work outdoors.


you mean all fittings should be compression type?

tnx,

micromind 05-06-2008 09:58 PM

One noticeable difference is that EMT can be cut, bent, then slipped into the fittings. Rigid must be screwed into fittings, though slip-in (threadless) fittings are made, as are 3 piece couplings (unions, sort of). You have to plan a rigid job out way far ahead. Most guys who run rigid absolutely hate to use 3 piece or threadless fittings. Even when I have no choice, it makes me feel as though I've lost some sort of a battle.

I can't think of anyplace in a residence where you'd need to run rigid, except the overhead service mast. Maybe somewhere in the garage where you're likely to smash into it with a car, but what would it be mounted to?

Alot of industrial places require it for protecting big feeders, where damage would make a big bang. I don't think I've ever run 4160 volts or higher in anything but rigid. That makes a MUCH bigger bang, btw. I've installed PVC coated rigid in water and sewer plants where corrosion is a problem.

EMT will work just fine for your project, plus it's much easier to work with.

Rob

P.S. There are 2 types of rigid conduit, regular rigid, and IMC. Intermediate metal conduit. IMC threads like rigid, but it's about 1/2 as thick-walled. Still pretty tough, but bends much easier.

micromind 05-06-2008 10:02 PM

EMT fittings; Compression, AKA raintight, weathertight, watertight (though they'll leak if submerged) are for use either indoors or out. Setscrew fittings are suitable for dry locations only.

Rob

analogmusicman 05-07-2008 12:42 AM

just sumpin a bit off topic:
don't know exactly where I saw this, maybe the discovery channel, the program was about the guys who go up in helicopters to work on high tension lines...one guy got fried and fell to the ground, he now works minus arms and legs still for the same utility. (but not on high wires)
anyone else see that?

tnx,


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