Chinese Conduit?

[Fulthrotl]

True. I was sent to the wholesale house as a young apprentice for a stick of 2-1/2" conduit. I returned with EMT. Still have the butt scars to show for it.

Electrical Mechanical Tubing

not EMC.....

around here, it's GRC or Conduit for sturdy pipe

emt is called steeltube or thinwall

 

[Fulthrotl]

I know of a plant where they used IMC for airlines just because they had a lot of it laying around, it started spliting at 120 psi.

thats why you use ocal for air lines.. the plastic coating makes it stronger. geez. everyone knows that.

 

[hillbilly1]

I hear on so many jobsites "I'm going to run some Tubing and pull some wire.":lol:

 

[readydave8]

I often call it conduit so that people will know what I'm talking about. Like calling a lamp a bulb.

 

[kbsparky]

.... Like calling a lamp a bulb.

I have a lamp at my house ... I put bulbs in it. :blink:

 

[kwired]

True. I was sent to the wholesale house as a young apprentice for a stick of 2-1/2" conduit. I returned with EMT. Still have the butt scars to show for it.

So you could have brought back RMC, IMC, PVC, FMC, LTFMC, LTFNMC and any of those would have been what was asked for

 

[GeorgeB]

The difference being?

Your question is more reasonable than the answers you are getting.

In the USA, "metallic conduit", which I won't define other than as a raceway to carry "something", there is stiff stuff and flexible stuff. The stiff, which must be bent with some sort of tool (the Incredible Hulk notwithstanding<g>), exists as "EMT", "IMC", and "RMC" generally thought of as electric metallic tubing, intermediate metal conduit, and rigid metal conduit.

LONG AGO, just EMT and RMC were common to the plant where I hung around as a kid. We called them "thinwall" and "rigid".

Today, EMT is heavily used in commercial buildings to contain insulated (usually THWN) conductors from panelboards to outlets. In MOST residential, "NM" cable would be used for this application. EMT is USUALLY galvanized steel, but there are less common and more pricey options ... plastic coated, painted, and I THINK stainless. In the standard galvanized, it is inexpensive. In my area, awning manufacturers even use it for framework, welding (yeah, galvanized) and bending as required. A few cities have been discussed here as requiring it for residential wiring ... no NM or UF type cabling.

RMC is made to the same dimensions as Schedule 40 pipe with tapered male threads, (NPT, not BSPT to my knowledge) and couplings are straight ... thus difficult to make pressure tight ... note that electrohydraulics is my area of expertise, so I am familiar with the concept of pressure tight and that tapered pipe eventually probably won't be ... we don't use it over 1/4" pipe size unless required for some (dumb?) reason.

IMC is, AFAIK, a newer product. It has OD and threading the same as RMC (EMT is not threaded). It is thinner wall and lighter weight than RMC. It is made from higher strength steel than RMC, and has similar physical properties. For a heavily loaded mast, many feel it to be the product of choice. Certainly if one "size" larger is used than RMC, it is still lighter and the larger section makes it stiffer.

If I'm burying, it is legal, but "many" (no source cited) feel it is less tough than RMC as related to corrosion. The zinc thickness specification is the same. A quick Google search turns up http://o.b5z.net/i/u/10069179/f/Conduit_Standards_and_Specifications.pdf from one manufacturer. The Steel Conduit Association, http://www.steelconduit.org/qa_home.htm has more detail as well.

I "ain't no lectrishun", and this may be a little off, but not much.

George

 

[iwire]

EMT is not conduit.

I agree and I agree it is important to know that.


The CMP also agrees as they had to change from

Ambient Temperature Adjustment for Conduits Exposed to Sunlight On or Above Rooftops

to

Ambient Temperature Adjustment for Circular Raceways Exposed to Sunlight on or Above Rooftops

 

[augie47]

I agree and I agree it is important to know that.


The CMP also agrees as they had to change from


to

So, if one elects to run a 2 x 2 square raceway there would be no
ambient derating ?

 

[hillbilly1]

I agree and I agree it is important to know that.


The CMP also agrees as they had to change from


to

Other than political correctness, calling EMT conduit, does not change the way it is used. RMC, IMC is a very small percentage of what is run in the US, even in Industrial, it is not used that much except for certain applications.

 

[renosteinke]

I can see it now ... sent for 'conduit,' he returns with a roll of flex. But the NEC calls it 'conduit ...."

Reminds me of a guy who would hand you a screwdriver if you ever asked for his Kleins. Hope he likes working on motors- I send him whenever I need a 'peckerhead.'

Back to "Chinese conduit" ... I haven't seen that yet, but anything is possible. I have encountered batches of EMT that just 'felt wrong' or tended to ripple in the bends. It's all in the steel, and the handling. Nobody's perfect.

Maybe a little 'primer' on pipe making is in order.

The steel comes in as a big coil, like a giant roll of toilet paper. It is unrolled, re-rolled lengthwise into a tube shape, and the seam welded.

The seam area is induction heated, and the metal pressed together without any flux, rod, or filler. Excess metal is scraped off both the inside and outside faces of the weld. This, btw, is the only physical difference between 'RMC' and "Schedule 40" pipe; plumbing pipe is not required to be 'smooth' inside.

Once welded, the seam area is annealed- again, using induction. At no time is the entire pipe made red-hot. The pipe is cooled and cut to length.

Since the pipe has been welded, it has a distinct bow. So, it is straightened. Then it is 'finished;' that is, it's plated, threaded, labled, all that fun stuff. At some point, a ram is passed through the pipe to remove and loose waste from the welding process.

Inspections occur at every step of the process. Exactly what inspections and tests depends upon the nature of the pipe. For example, well casings will be individually pressure tested, while plumbing pipe will be 'sampled,' and electrical pipe will skip this test.

A wake up call to the steel industry: the samples of Chinese (non electrical) pipe I have seen are of an exceptionally good quality steel. You're not going to win if assume it's just more Chinese junk.

 

[hillbilly1]

Electrical Mechanical Tubing

not EMC.....

around here, it's GRC or Conduit for sturdy pipe

emt is called steeltube or thinwall

It's actually Metallic not mechanical.

 

[MJW]

My old teacher said conduit is made out of scrap cars, sometimes you get a Cadillac and sometimes you get a Yugo.

 

[sameguy]

I call it conduit, if you keep calling it tube then the fitters will say they need to run it. It is happening here in upstate NY, also with fiber "light tube". This is for real! we have been fighting them off; and after Madoff the Carps. are starting an "electrical union"!!

 

[sameguy]

I have seen Saudi Arabian "ridgid" not good. It was in GE packaged cogens. I repiped, rewired to US standards.

 

[Strife]

Plumbers use "pipe"
Electricians use CONDUIT

While Art 100 defines raceway, it doesn't define conduit. In absence of a formal definition the NFPA Manual of Style refers us to the Merriam-Webster, 11th Collegiate Dictionary, which defines conduit as

 

[K8MHZ]

Plumbers use "pipe"
Electricians use CONDUIT

Pipe fitters use pipe.

Plumbers use pipe and tubing.

Electricians use pipe, tubing, conduit, tray, duct and tape.

 

[Cow]

Great, it seems this forum now has another topic to beat to death....:blink:

yaaaaay for political correctness.:roll:

 

[iwire]

Political correctness has nothing to do with it.

 

[Fulthrotl]

It's actually Metallic not mechanical.

can we not clog the thread with facts please? thank you.

honestly have no idea why i said mechanical instead of mettalic. duh.