# Stainless Steel Conduit



## BBQ (Nov 16, 2010)

Paul Gabbert said:


> I am being asked to provide a machine using stainless steel conduit and fittings. It is my understanding that stainless steel conduit should not be considered as the grounding conductor. I can't find a refrence to this in the NEC. Can you offer direction?


See 250.118, the NEC will allow you to use it as an EGC, it would not surprise me if the job specs will not allow it.


----------



## shiznit60 (Nov 18, 2010)

BBQ said:


> See 250.118, the NEC will allow you to use it as an EGC, it would not surprise me if the job specs will not allow it.


 thats news to me i thought they changed it that conduit was no longer considered to be suitable grounding and you were always to supply a seperate ground.


----------



## danickstr (Mar 21, 2010)

ya 250.118 says even emt/imc/rmc to flex/seal-tite is still grounding, if the flex piece is not over 6 feet, it is not for a vibrating motor, and the circuit is 20 amps or less.

Is that 6 feet total or can you put in several 6 foot chunks and spearate them with sections of emt?


----------



## John Valdes (May 17, 2007)

shiznit60 said:


> thats news to me i thought they changed it that conduit was no longer considered to be suitable grounding and you were always to supply a seperate ground.


Its still okay as far as the 2008. Metal conduit only and see the post below regarding flexible metal conduit. :thumbsup:


----------



## raider1 (Jan 22, 2007)

shiznit60 said:


> thats news to me i thought they changed it that conduit was no longer considered to be suitable grounding and you were always to supply a seperate ground.


Why would you think that?

Properly installed EMT is a much better fault current path than an insulated equipment grounding conductor.

Chris


----------



## danickstr (Mar 21, 2010)

Chris I agree to a degree. Emt conduit isn't good at taking damage and still working, where a EGC wire will dangle there still connected. 


We have repaired many damaged sticks of emt that were ripped out of their connectors, with the working wires dangling out there for all to see. They also rarely call when it happens, I just ask if they want that fixed. :thumbup:


----------



## MDShunk (Jan 7, 2007)

If you're using stainless conduit, this is probably a food, dairy, or pharmaceutical job. These are washdown areas. Places that do regular washdown typically spec that you must pull an actual ground. They don't want to gamble on resistive crud building up in the threads of the connections. There is nothing in NFPA 70 or NFPA 79 that would prohibit using stainless conduit as the equipment grounding conductor, however. 

By the way, special die teeth and special cutting fluid for stainless, in case you didn't know.


----------



## BuzzKill (Oct 27, 2008)

raider1 said:


> Why would you think that?
> 
> Properly installed EMT is a much better fault current path than an insulated equipment grounding conductor.
> 
> Chris


Hmmm, code minimum huh? Also depends on the installer of the conduit, connectors, boxes, etc. (hence: properly installed) however, pull the extra wire as a backup...everything will not get checked.


----------



## mattsilkwood (Sep 21, 2008)

If they want SS conduit there is money in there to run a ground. 
Just be sure you are sitting down when you price the pipe, I ran some a couple months ago and it was $110 for a stick of 3/4.


----------



## captkirk (Nov 21, 2007)

That would be a good argument for the mythbusters....Which path has the least resistance....


----------



## MDShunk (Jan 7, 2007)

mattsilkwood said:


> If they want SS conduit there is money in there to run a ground.
> Just be sure you are sitting down when you price the pipe, I ran some a couple months ago and it was $110 for a stick of 3/4.


The reality is that most places that think they need stainless steel RMC or IMC can usually get along just as well with aluminium or Rob Roy.


----------



## MDShunk (Jan 7, 2007)

captkirk said:


> That would be a good argument for the mythbusters....Which path has the least resistance....


Actually, if you Google up a report called the "Georgia Tech Model", that work has already been done.


----------



## BuzzKill (Oct 27, 2008)

HA! Go GT, Go engineers!!!


----------



## mattsilkwood (Sep 21, 2008)

MDShunk said:


> The reality is that most places that think they need stainless steel RMC or IMC can usually get along just as well with aluminium or Rob Roy.


 Yea we ran a bunch of aluminum on that job. That's just about all anyone uses around here. 
Just for the record, aluminum sucks.


----------



## BuzzKill (Oct 27, 2008)

mattsilkwood said:


> Yea we ran a bunch of aluminum on that job. That's just about all anyone uses around here.
> Just for the record, aluminum sucks.


why?
easy to thread, handle, cut, etc.


----------



## Rudeboy (Oct 6, 2009)

captkirk said:


> That would be a good argument for the mythbusters....Which path has the least resistance....


That's awesome. E-mail them.

Not joking, that really would be cool.
:thumbsup:


----------



## MDShunk (Jan 7, 2007)

BuzzKill said:


> why?
> easy to thread, handle, cut, etc.


Jobs being done with aluminium are often sanitary jobs, where they really don't tolerate wrench marks or vise marks on the pipe. That means using the Rob Roy tristand vise jaws and using the rubber coated shoes in the 555. Installation with strap wrenches or chain wrenches.


----------



## mattsilkwood (Sep 21, 2008)

BuzzKill said:


> why?
> easy to thread, handle, cut, etc.


 It's cheaper. When I say everyone I'm talking about food processing plants.


----------



## MDShunk (Jan 7, 2007)

mattsilkwood said:


> Yea we ran a bunch of aluminum on that job. That's just about all anyone uses around here.
> Just for the record, aluminum sucks.


If you're in missouri, you probably have a bunch of cheese processing places. Is that what this was?


----------



## BuzzKill (Oct 27, 2008)

Rudeboy said:


> That's awesome. E-mail them.
> 
> Not joking, that really would be cool.
> :thumbsup:


I might very well be mistaken but I imagine it having something to do with aluminum not being "magnetized".


----------



## BuzzKill (Oct 27, 2008)

MDShunk said:


> Jobs being done with aluminium are often sanitary jobs, where they really don't tolerate wrench marks or vise marks on the pipe. That means using the Rob Roy tristand vise jaws and using the rubber coated shoes in the 555. Installation with strap wrenches or chain wrenches.


no no, just saying, aluminum might cost more, material wise, but it is easier to install, i.e., cost/benefit analysis-wise.


----------



## mattsilkwood (Sep 21, 2008)

MDShunk said:


> If you're in missouri, you probably have a bunch of cheese processing places. Is that what this was?


 To tell you the truth I don't know of any cheese plants. This was at a cold storage where they also do meat packing/ repacking. 
One of thier big rackets they have going this time of year is they take a cheap ham, repackage it in a Martha Stewart bag and sell it for 8 bucks a pound.


----------



## BuzzKill (Oct 27, 2008)

mattsilkwood said:


> To tell you the truth I don't know of any cheese plants. This was at a cold storage where they also do meat packing/ repacking.
> One of thier big rackets they have going this time of year is they take a cheap ham, repackage it in a Martha Stewart bag and sell it for 8 bucks a pound.


I looooove the meat industry!
Go meat! Go slaughter! Go hormones, antibiotics, pesticides! Woo hoo!


----------



## HARRY304E (Sep 15, 2010)

BuzzKill said:


> I looooove the meat industry!
> Go meat! Go slaughter! Go hormones, antibiotics, pesticides! Woo hoo!


Wow!


----------



## Jlarson (Jun 28, 2009)

MDShunk said:


> Jobs being done with aluminium are often sanitary jobs


Aw, sanitary jobs, what a PITA. Actually any job involving any conduit that you have to get out the special shoes, wrenches and tri stands for is a PITA to some degree.


----------



## HARRY304E (Sep 15, 2010)

Jlarson said:


> Aw, sanitary jobs, what a PITA. Actually any job involving any conduit that you have to get out the special shoes, wrenches and tri stands for is a PITA to some degree.


What is PITA :001_huh:


----------



## Jlarson (Jun 28, 2009)

HARRY304E said:


> What is PITA :001_huh:


pain in the ass


----------



## bobelectric (Feb 24, 2007)

palin is an ass?


----------



## MDShunk (Jan 7, 2007)

Jlarson said:


> Aw, sanitary jobs, what a PITA. Actually any job involving any conduit that you have to get out the special shoes, wrenches and tri stands for is a PITA to some degree.


Not to mention paper lab coat, hair net, booties, and washing your hands every time you walk from here to there.


----------



## Shorty Circuit (Jun 26, 2010)

Paul Gabbert said:


> I am being asked to provide a machine using stainless steel conduit and fittings. It is my understanding that stainless steel conduit should not be considered as the grounding conductor. I can't find a refrence to this in the NEC. Can you offer direction?


Stainless steel is a steel alloy with most of the same properties as other steel alloys with a few exceptions. It has a high chromium content. It will not tarnish or rust. 300 series with the least chromium content can be pitted by chloride ions, higher grades are immune. It is not magnetic. Therefore like aluminum conduit it will not create or add to a series inductive voltage drop even at higher frequencies such as 400 hz where some UPSs and MAs used to operate (don't know if they still have them.) It is also resistant to oxidizing where aluminum is not. It is also expensive. Whoever specified it must have had a good reason unless he just liked throwing money away. I'd guess it would be used where it will be run exposed in an area that needs to be kept very clean.


----------



## oldtimer (Jun 10, 2010)

Shorty Circuit said:


> Stainless steel is a steel alloy with most of the same properties as other steel alloys with a few exceptions. It has a high chromium content. It will not tarnish or rust. 300 series with the least chromium content can be pitted by chloride ions, higher grades are immune. It is not magnetic. Therefore like aluminum conduit it will not create or add to a series inductive voltage drop even at higher frequencies such as 400 hz where some UPSs and MAs used to operate (don't know if they still have them.) It is also resistant to oxidizing where aluminum is not. It is also expensive. Whoever specified it must have had a good reason unless he just liked throwing money away. I'd guess it would be used where it will be run exposed in an area that needs to be kept very clean.


 Correct: Like in a clean room of a plant that makes prescription drugs etc. I have worked in such a plant at times, and there was stainless steel spec'd,for some critical areas.


----------



## sparky970 (Mar 19, 2008)

We ran exposed PVC everywhere when we built the Foster Farms chicken plant. Within a year or so, working for a different contractor, we had replaced nearly all the PVC with Ocal from ground level to about 20'. PVC doesn't hold up well when people climb all over it during washdown. It's amazing how much chicken goo can get inside conduits.


----------



## brian john (Mar 11, 2007)

MDShunk said:


> I\
> They don't want to gamble on resistive *crud* building up in the threads of the connections.
> 
> 
> Or CURD if this is a dairy.:laughing:


----------



## Clutch (Jul 25, 2010)

*size directly affects PITA level*

I have been running 3 and 4 inch rob roy for about a month and a half. We havent been using any special wrenches or clamps. The big pipe seems to take it pretty well compared to the smaller stuff.

We do put some marks on the pipe and occasionaly tear it but the plant doesnt want to pay for the extra wrenches /clamps. So we are as careful as possible. 

We do use stainless steel corn clamps and I have found I MUST use no ox or the fittings will gall (spelling) and I can not get them off.


----------



## Jlarson (Jun 28, 2009)

MDShunk said:


> Not to mention paper lab coat, hair net, booties, and washing your hands every time you walk from here to there.


Don't remind me.


----------



## mattsilkwood (Sep 21, 2008)

MDShunk said:


> Not to mention paper lab coat, hair net, booties, and washing your hands every time you walk from here to there.


 How did you come out with your search for arc rated hair and beard nets? The cheapest ones I found were $22 a piece.


----------



## MDShunk (Jan 7, 2007)

mattsilkwood said:


> How did you come out with your search for arc rated hair and beard nets? The cheapest ones I found were $22 a piece.


Found some made out of paper from Kimberly Clark for something like 30 bucks for a big box full.


----------



## mattsilkwood (Sep 21, 2008)

MDShunk said:


> Found some made out of paper from Kimberly Clark for something like 30 bucks for a big box full.


 Got a link?


----------

