# class 1 hazardous location install question.



## slickvic277 (Feb 5, 2009)

Class 1. But what division?


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## jefft110 (Jul 7, 2010)

Not sure. It was in a paint mixing room.
I want to say it said d on the motor.


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## wildleg (Apr 12, 2009)

this is a great time for you to pull out your code book and read the applicable sections for yourself. start with 500, 501 and 502. then find the one that applies to paint booths and read it.


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## jefft110 (Jul 7, 2010)

Thanks. Nice way of saying you haven't the answer.
I checked, and I didn't see anything regarding the use of teflon tape.


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## frenchelectrican (Mar 15, 2007)

jefft110 said:


> Thanks. Nice way of saying you haven't the answer.
> I checked, and I didn't see anything regarding the use of teflon tape.


 
Not excatally he try to guide you to the right spot and I know you did check it but look little closer and from my experince NO teflon tape in expolison proof devices the reason why one is bonding properly and second thing that the UL test it with the X numbers of thread screwed on so they will know what work and what not.

{ IIRC it was 7 threads but not sure that will cover all of it }

Merci.
Marc


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## wildleg (Apr 12, 2009)

you read through the sections looking for the answer, but you still can't tell us if its class 1 div 1 or div 2, or what the rating is of the motor ? I'm assuming it's div 2 since you didn't mention xp flex. if you want answers you are going to have to at least provide some information; reading through those portions of the code book and understanding all the information is no small task. Do yourself a favor and really read them and not just skim over them. what is the classification of the area ? Portions of 516 may also apply. what code cycle are you on ?

It's my opinion that teflon tape is not allowed because it does not allow the release of explosive gasses that the threaded connection is supposed to allow. Some people believe 501.30 prohibits the use of teflon tape because the tape reduces grounding effectiveness (although you can easily check for yourself after assembling the pipe that it doesn't, because the teflon gets ripped away at the tightened portions of the threads).

here's a good discussion of the teflon tape:
http://forums.mikeholt.com/showthread.php?t=110639&highlight=teflon+tape

you should be able to find the answer for yourself on the junction box.


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## raider1 (Jan 22, 2007)

> It's my opinion that teflon tape is not allowed because it does not allow the release of explosive gasses that the threaded connection is supposed to allow.


I agree, the threads of explosion proof equipment are designed to allow the hot expanding gasses from an explosion to pass over a set number of threads that will cool the gasses to a point that when they escape the enclosure they will not be hot enough to ignite any explosive atmosphere that may exist outside of the enclosure.

Chris


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## raider1 (Jan 22, 2007)

> Well, today we were tapping a motor that had a two-wire, 18" pig tail and did not have a ground wire..obviously relying on the explosion-proof flex conduit for a bond? My question is, do the threads properly bond with the teflon?


Check out 501.30(B). This section prohibits the use of flex as the sole ground-fault current path in a Class 1 location.

Chris


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## Shorty Circuit (Jun 26, 2010)

jefft110 said:


> The foreman for a company I just started working for insists we use teflon tape on the male threads when running rigid pipe inside a class 1 hazardous area. I silently questioned this (not having too much experience with explosion proof methods) thinking that it may interrupt the bonding of the pipe.
> Well, today we were tapping a motor that had a two-wire, 18" pig tail and did not have a ground wire..obviously relying on the explosion-proof flex conduit for a bond? My question is, do the threads properly bond with the teflon?
> 
> Also, we had to use a j-box between the 12" flex and the conduit seal. Should there have been another conduit seal between the j-box and the flex leading into the motor?
> ...


No, you cannot interrupt the integrity of the electrical continuity of the raceway in any way. Apply an approved sealant to make the raceway vapor tight from the outside of the threaded connections AFTER it is assembled. Don't forget the vapor seals inside the pipe where it penetrates the boundary of the class one area.

The vapor seal outside the raceway prevents combustable or explosive mixtures of air and solvents from exposure to any spark such as at a lightswitch which might ignite it. It also protects the wiring and devices from attack by corrosive vapors if they are present. The vapor seal inside the pipe prevents those vapors from escaping beyond the class one zone where they might be ignited or cause corrosive damage should they ever somehow enter the raceway.


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## John Valdes (May 17, 2007)

Good discussion and some very good information. My question would be, why no EGC? I mean if your foreman is concerned about the integrity of the conduit run why not just make things easy for all concerned and pull an EGC?
I did not know it was a violation to use the tape, but common sense would tell me not to use it.


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## raider1 (Jan 22, 2007)

Shorty Circuit said:


> No, you cannot interrupt the integrity of the electrical continuity of the raceway in any way.


I agree that Teflon tape may interrupt the bonding path required for Class 1 locations.




> Don't forget the vapor seals inside the pipe where it penetrates the boundary of the class one area.


This is called a boundary seal and is used to minimize the passage of flammable vapors from a Division 1 location to a Division 2 location or from a Division 2 location to an unclassified location.



> The vapor seal outside the raceway prevents combustible or explosive mixtures of air and solvents from exposure to any spark such as at a lightswitch which might ignite it.


It is practically impossible to seal the outside of the raceway or enclosure to be gas tight. The code requires that the threaded connections be such that if an explosion occurs within the raceway or enclosure that the escaping gasses be cooled by passing over enough threads to cool the vapors to a point that they can't ignite any combustible atmosphere outside of the raceway or enclosure.



> It also protects the wiring and devices from attack by corrosive vapors if they are present.


This would be corrosion protection and would be needed only if there were a corrosive environment. Not all Class 1 locations are a corrosive environments.

Chris


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## jefft110 (Jul 7, 2010)

John Valdes said:


> Good discussion and some very good information. My question would be, why no EGC? I mean if your foreman is concerned about the integrity of the conduit run why not just make things easy for all concerned and pull an EGC?
> I did not know it was a violation to use the tape, but common sense would tell me not to use it.


We did pull a ground to the j-box (and of course bonded the box) right before the motor. The motor, itself, didn't have a egc included in the whip. That's what was worrying me about using the teflon on a motor that uses the conduit for its ground.
It never even occurred to me about the threads being a release for expanding gasses. I'm going to show him this thread as well as the the Mike Hold thread.

Thanks everyone for the responses.


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## slickvic277 (Feb 5, 2009)

jefft110 said:


> We did pull a ground to the j-box (and of course bonded the box) right before the motor. The motor, itself, didn't have a egc included in the whip. That's what was worrying me about using the teflon on a motor that uses the conduit for its ground.
> It never even occurred to me about the threads being a release for expanding gasses. I'm going to show him this thread as well as the the Mike Hold thread.
> 
> Thanks everyone for the responses.



Why not just try using the code book?.....Not trying to be a dck, I'm just sayin'


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## jefft110 (Jul 7, 2010)

raider1 said:


> Check out 501.30(B). This section prohibits the use of flex as the sole ground-fault current path in a Class 1 location.
> 
> Chris


I'm going off the '05 book (not good I know) but 501.30(b) but exception 1 states flex 6' or less with fittings listed for grounding is acceptable in lieu of installing bonding jumpers. 
Has this changed in the '08 book?

We used a 12" braided explosion proof flex whip.


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## jefft110 (Jul 7, 2010)

slickvic277 said:


> Why not just try using the code book?.....Not trying to be a dck, I'm just sayin'


Actually I'm trying. I've only been doing this off and on for a couple of years, and am questioning my boss.

BTW, it seems to me that almost every question on this forum could be answered with "why not use the code book?" 

It would be a rather boring place though, huh?


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## slickvic277 (Feb 5, 2009)

jefft110 said:


> Actually I'm trying. I've only been doing this off and on for a couple of years, and am questioning my boss.
> 
> BTW, it seems to me that almost every question on this forum could be answered with "why not use the code book?"
> 
> It would be a rather boring place though, huh?


:laughing: The last thing this place is, is boring. I was saying use the code book _*because your questioning the boss*_. He probably be much more impressed with that then if you showed him a bunch of opinions from an internet forum.

Speaking of opinions, mine is, no to the teflon tape. Make sure you engage 5 full threads per the code. The location of your last conduit seal is fine and I would have pulled a ground as well. :thumbsup:


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## Shorty Circuit (Jun 26, 2010)

raider1 said:


> I agree that Teflon tape may interrupt the bonding path required for Class 1 locations.
> 
> 
> 
> ...


"This would be corrosion protection and would be needed only if there were a corrosive environment. Not all Class 1 locations are a corrosive"

True. He didn't say what division it is or what the anticipated hazard was. I recently did a sovlent mixing room and managed to keep all of my elecrical work out of class 1 division 1 and restricted them to class 1 division 2. Still I specified for the division 1 criteria.


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## raider1 (Jan 22, 2007)

jefft110 said:


> I'm going off the '05 book (not good I know) but 501.30(b) but exception 1 states flex 6' or less with fittings listed for grounding is acceptable in lieu of installing bonding jumpers.
> Has this changed in the '08 book?
> 
> We used a 12" braided explosion proof flex whip.


Yes, this is a new change for the 2008 NEC.

Chris


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## John Valdes (May 17, 2007)

raider1 said:


> Yes, this is a new change for the 2008 NEC.
> 
> Chris


It may be just fine depending on the code cycle you are on, and at the direction of the AHJ. However, I am of the opinion that if I know there is a change to a previous version I always use the current provision/article/table. That being the 2008.


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## jefft110 (Jul 7, 2010)

raider1 said:


> Yes, this is a new change for the 2008 NEC.
> 
> Chris


What do you do if the motor doesn't provide you a ground whip? 

Should we've hard piped directly into the motor? I have always thought that common practice is to flex into a motor simply for the give with vibration.


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## Mogie (May 26, 2010)

jefft110 said:


> What do you do if the motor doesn't provide you a ground whip?
> 
> Should we've hard piped directly into the motor? I have always thought that common practice is to flex into a motor simply for the give with vibration.


Never hard pipe directly into a motor, due to the vibration. If you've used braded explosion-proof flex, technically this provides an adequate ground. In terms of the teflon tape, this is not acceptable for Class 1 installations of any division. If you are after a completely vapor-tight and ground-enhanced installation, use a 'copper-coat'. This is a compound like a plumber's pipe dope, but infused with copper dust or flakes designed to enhance the ground connection established by your 5-thread connection required by the code. In any case, I would always pull an EGC.
Good luck w/the exchange w/your boss!


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## Shorty Circuit (Jun 26, 2010)

jefft110 said:


> What do you do if the motor doesn't provide you a ground whip?
> 
> Should we've hard piped directly into the motor? I have always thought that common practice is to flex into a motor simply for the give with vibration.


I'd connect the ground wire to the motor frame.

I use Sealtite LA or Sealtite SA outdoors and in wet locations and Greenfield indoors in dry locations for the final fitup. For a small motor MC should be OK too. I'd use more than a foot though. BTW, I use this on all HVAC equipment, especially condensers.

Mogie, thanks for the heads up about copper coat.


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## wildleg (Apr 12, 2009)

Shorty Circuit said:


> I'd connect the ground wire to the motor frame.
> 
> I use Sealtite LA or Sealtite SA outdoors and in wet locations and Greenfield indoors in dry locations for the final fitup. For a small motor MC should be OK too. I'd use more than a foot though. BTW, I use this on all HVAC equipment, especially condensers.
> 
> Mogie, thanks for the heads up about copper coat.


dude, its a classified area


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## Shorty Circuit (Jun 26, 2010)

wildleg said:


> dude, its a classified area


dude :blink:, all areas are classified. :no: The only difference is what classification they are in. :yes::whistling2:


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## hotwire1955 (Jan 27, 2009)

You do not need a nother seal between the j-box and the motor as long as there are not any sparking devices in the j-box.
Installation is class1 div.1 location if they are mixing flammable liquids.
As for the 05 and 08 code nothing has changed as far as 501.30(B). The bonding jumper can be deleated only in class1 div.2 locations with conditions being meet.
Most flex braided fittings are listed for grounding


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## slickvic277 (Feb 5, 2009)

Shorty Circuit said:


> dude, all areas are classified. :no: The only difference is what classification they are in. :yes::whistling2:


Actually no,:no: there are area's that are Unclassified.

500.2 definitions.

Unclassified Locations. Locations determined to be neither Class I, Division 1; Class I, Division 2; Class I, Zone 0; Class I, Zone 1; Class I, Zone 2; Class II, Division 1; Class II, Division 2; Class III, Division 1; Class III, Division 2; Zone 20; Zone 21; Zone 22; or any combination thereof. 




hotwire1955 said:


> You do not need a nother seal between the j-box and the motor as long as there are not any sparking devices in the j-box.
> *Installation is class1 div.1 location if they are mixing flammable liquids*.
> As for the 05 and 08 code nothing has changed as far as 501.30(B). The bonding jumper can be deleated only in class1 div.2 locations with conditions being meet.
> Most flex braided fittings are listed for grounding


I know what your trying to say but i think it's better put like this;

Division I = Usually, or can, or does, exist under normal conditions

Division II = Only, under abnormal conditions

Of course this is a super micro summary. I think it makes it easier to remember the 2 divisions.


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## hotwire1955 (Jan 27, 2009)

slickvic277 said:


> Actually no,:no: there are area's that are Unclassified.
> 
> 500.2 definitions.
> 
> ...


????:001_huh:


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## slickvic277 (Feb 5, 2009)

hotwire1955 said:


> ????:001_huh:



What part don't you understand?

_P.S._ I was bustin' chops with the unclassified definition....


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## paul_arc (Mar 31, 2009)

correct me if im wrong but you need something like this, not teflon tape. This aids in the conductivity on the threads. Its in the NEC to be used on all rigid runs but no one ever does.


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## hotwire1955 (Jan 27, 2009)

paul_arc said:


> correct me if im wrong but you need something like this, not teflon tape. This aids in the conductivity on the threads. Its in the NEC to be used on all rigid runs but no one ever does.


 ok your wrong ,it's listed for copper to copper ,copper to brass,copper to bronze connections


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## paul_arc (Mar 31, 2009)

hotwire1955 said:


> ok your wrong ,it's listed for copper to copper ,copper to brass,copper to bronze connections


http://www.ajbsales.com/index_KOP.html


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## kwired (Dec 20, 2009)

wildleg said:


> ...It's my opinion that teflon tape is not allowed because it does not allow the release of explosive gasses that the threaded connection is supposed to allow. Some people believe 501.30 prohibits the use of teflon tape because the tape reduces grounding effectiveness (although you can easily check for yourself after assembling the pipe that it doesn't, because the teflon gets ripped away at the tightened portions of the threads)...





raider1 said:


> I agree, the threads of explosion proof equipment are designed to allow the hot expanding gasses from an explosion to pass over a set number of threads that will cool the gasses to a point that when they escape the enclosure they will not be hot enough to ignite any explosive atmosphere that may exist outside of the enclosure.
> 
> Chris





Shorty Circuit said:


> ... Apply an approved sealant to make the raceway vapor tight from the outside of the threaded connections AFTER it is assembled...
> The vapor seal outside the raceway prevents combustable or explosive mixtures of air and solvents from exposure to any spark such as at a lightswitch which might ignite it...





raider1 said:


> I agree that Teflon tape may interrupt the bonding path required for Class 1 locations.
> 
> 
> 
> ...


 
In Class 1 hazardous locations wiring methods are often called explosion proof which gives the wrong impression of the design of class 1 equipment. In a class 1 location because it is practically impossible to seal raceways and enclosures to be gas tight we design the system to be able to contain an explosion when it does happen.

The wiring methods are also designed to cool high pressurized hot gases when there is an explosion within to a safe temperature when it escapes so that it will not ignite flammable gases outside the raceway or enclosure. This cooling is done through the threaded raceway entries and through the machined or threaded surfaces of the enclosures and covers and other parts of fittings used. 

Sealing fittings are required within 18 inches of enclosures containing arcing parts because this is where the explosions are most likely to occur and we want to seal the raceways leaving the enclosure so we do not add to the volume of the interior of the enclosure with a long run of raceway, which will allow for more accumulation of fuel for the explosion.

Using sealants of any type on threads or mating surfaces inhibits this pressure relief and cooling feature of the wiring method and in most cases should be a violation of installation instructions. I'm pretty sure this is not a rule written in NEC but is the idea of the installation and is likely in almost all equipment instructions.

Outside of class 1 locations thread sealants should not really affect grounding continuity of raceways if they are tightened with wrenches, the threads will mash together through the sealant and make good contact. The whole idea of sealant is to fill gaps in the threads to prevent them from leaking, where there is no gaps there is metal to metal contact.


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## hotwire1955 (Jan 27, 2009)

paul_arc said:


> http://www.ajbsales.com/index_KOP.html


 ok I'M wrong


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## jefft110 (Jul 7, 2010)

Update.

I finally challenged my boss and showed him this thread on my blackberry, and referenced the NEC. He was actually very responsive.
Paraphrasing:
"I majored in chemical engineering at MSU, and the whole concept is to keep oxygen outside of the raceway. No oxygen, no explosion, period."

Kind of makes sense.


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## hub (Jun 11, 2008)

*old electrician*

Tell your boss I have taken a 6 hour test and passed for my journey man. Study the code for over forty years, an also have a degree. He wrong, wrong, and wrong.:no: He is the reason I have job security.


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## butcher733 (Aug 4, 2012)

Your boss should be clubbed like a baby seal.


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## glen1971 (Oct 10, 2012)

hub said:


> Tell your boss I have taken a 6 hour test and passed for my journey man. Study the code for over forty years, an also have a degree. He wrong, wrong, and wrong.:no: He is the reason I have job security.


The better question to the OP is does he still work for the same employer after 4 1/2 years...


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## don_resqcapt19 (Jul 18, 2010)

jefft110 said:


> I'm going off the '05 book (not good I know) but 501.30(b) but exception 1 states flex 6' or less with fittings listed for grounding is acceptable in lieu of installing bonding jumpers.
> Has this changed in the '08 book?
> ...


That exception would not apply to a motor. Look at list item 3 in the exception. The motor is a power utilization load.


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## FaultCurrent (May 13, 2014)

We used to use red lead in the old days but now it's copper coat. But this is more to do with protecting field made threads than anything else.

300.6 Where corrosion protection is necessary and the conduit is
threaded in the field, the threads shall be coated with an approved
electrically conductive, corrosion-resistant compound.

So if the threads are factory made no compound. If teflon tape is used on field made threads no bueno. 

Can teflon tape be used on explosionproof fittings? Why not? Do you really think the tape will survive and insulate the connection once you tighten it down? 

But for myself, I would use the copper coat on field made threads, and on everything underground, and nothing on the remainder of the job. 

Do you see copper coat or similar on all rigid threads made in the field, explosion proof or not jobs? I think not


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