Paint booth question

[jerryatric]

Booth manufacturer supplied fixtures to be installed as in 516.4(c)(3). The back of the fixtures ( in the booth ceiling) will be in the supply plenum. As air will be recirculated during the curing process the supply plenum will be class I div. 2 as I understand it : 516.3(D)(4)(2)(a). Fixtures are rated class I div. 2. Do I need a seal at each individual fixture or just at the boundaries ?Thanks for any help.

 

[rbalex]

I would be more concerned about recirculating air from the Division 1 location inside the booth.

Since I'm not familiar with the booth's actual set up but assuming that the plenum is correctly classified Division 2, the luminaries are rated properly and marked "factory sealed", no additional field installed seals are required for the luminaries themselves except in the highly unlikely case where the raceway entries are 2" or larger.

 

[jerryatric]

Bob , thanks for your response. Concerning the classification of the supply plenum , instrumentation and lel monitors will control percentages of outside , recirculated and exhaust air. I finally got a fixture in hand and now have some info :
fluorescent - 6 T5 lamps , UL std. 844 , 1590 , ETL label , op. temp. code T4A , max. ambient temp. 40 C, max. operating temp. 120 C. Rated groups A,B,C,D - class I division 2 , has interlock switch for the lens/door , has factory installed threaded hub and 6 foot whip - type TC-ER cable . There is no internal seal . If rated connectors are used can they be installed without a seal at each fixture ? Thanks again.

 

[rbalex]

I'm only mildly concerned about the interlock switch. Check how it is specifically marked. Make sure it would comply with Section 501.115(B)

Everything else indicates the luminaire itself complies with Section 501.130(B)(1). Since the luminaire is not explosionproof, a seal would be useless to start with.

BTW, I got carried away before when referencing a seal for a 2 inch conduit entry. That only applies in Division 1.

 

[jerryatric]

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Bob , thanks for your response. Concerning the classification of the supply plenum , instrumentation and lel monitors will control percentages of outside , recirculated and exhaust air. I finally got a fixture in hand and now have some info :
fluorescent - 6 T5 lamps , UL std. 844 , 1590 , ETL label , op. temp. code T4A , max. ambient temp. 40 C, max. operating temp. 120 C. Rated groups A,B,C,D - class I division 2 , has interlock switch for the lens/door , has factory installed threaded hub and 6 foot whip - type TC-ER cable . There is no internal seal . If rated connectors are used can they be installed without a seal at each fixture ? Thanks again.

Thanks for all your help. The plan is to use 4 inch square boxes to feed light fixtures in this paint booth - backs of fixtures are in the return plenum above the booth ( class I div. 2) An older thread referenced 501.30(A) , 250.100 and 250.92(B) (2) - (4) . I believe I understand these concerns but I am unclear on reference to possible extra hardware and or labor to properly bond said boxes. The plan is to install MC cable between the boxes using approved saddle type connectors with locknuts and fixtures connecting to the boxes via factory installed TC cable whip with cable connectors approved for class I div. 2 . Other than the typical connection of the grounding conductors to the box , what would be required to be compliant ? Haven't ever used these wiring methods in class I division 2 area , trying to get comfortable . Thanks again.

 

[rbalex]

I'm not sure which older thread you're referring to, however, I am pretty sure it is referring to the fact that a double locknut or a locknut/bushing combination is unacceptable for bonding in a classified location. This is primarily because a locknut cannot achieve a five thread engagement. The fact that the raceway involved may have five threads engaged is irrelevant; each element of the bond (raceway, locknut and/or bushing) must comply. Where locknuts are used for mechanical connections, an auxiliary bonding means is necessary.

 

[jerryatric]

I'm not sure which older thread you're referring to, however, I am pretty sure it is referring to the fact that a double locknut or a locknut/bushing combination is unacceptable for bonding in a classified location. This is primarily because a locknut cannot achieve a five thread engagement. The fact that the raceway involved may have five threads engaged is irrelevant; each element of the bond (raceway, locknut and/or bushing) must comply. Where locknuts are used for mechanical connections, an auxiliary bonding means is necessary.

Bob , thanks again for keeping me straight again.

Mike

 

[jerryatric]

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Bob , thanks again for keeping me straight again.

Mike

I am installing water level sensors in a pit (Class I , Div.1) using twisted pair shielded cable - jacket and shield removed in the conduit seal at the sensor , jacket intact in the CI D1 x unclassified boundary seal , and adhesive type heat shrink on cable end at control cabinet ( non exp. proof in unclassified area ) . Is this a correct install ? As always , much thanks.

 

[rbalex]

You might want to review Section 501.15(D)(1) Exception.

How is the Division 1/unclassified boundary established? The sealing method itself seems fine but there's usually a Division 1/Division 2 boundary somewhere in the run.

The heat shrink in the unclassified location end is fine.

 

[jerryatric]

I am installing water level sensors in a pit (Class I , Div.1) using twisted pair shielded cable - jacket and shield removed in the conduit seal at the sensor , jacket intact in the CI D1 x unclassified boundary seal , and adhesive type heat shrink on cable end at control cabinet ( non exp. proof in unclassified area ) . Is this a correct install ? As always , much thanks.

The conduit run originates in a pit below a paint booth which is located in a hangar, emerging through the slab in an area separated from the actual hangar area and continues up to an equipment room. If I follow you correctly on reviewing 501.15(D)(1) exception , the conduit seals are close to the sensors , so I am thinking I'll take the cable prep back a little farther so that the end of the cable is encapsulated in the sealing compound. Thanks again.

 

[rbalex]

The conduit run originates in a pit below a paint booth which is located in a hangar, emerging through the slab in an area separated from the actual hangar area and continues up to an equipment room. If I follow you correctly on reviewing 501.15(D)(1) exception , the conduit seals are close to the sensors , so I am thinking I'll take the cable prep back a little farther so that the end of the cable is encapsulated in the sealing compound. Thanks again.

Actually, the Exception says you don't have to remove the shields. Removing the jacket back to the seal is a good idea.

 

[jerryatric]

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Actually, the Exception says you don't have to remove the shields. Removing the jacket back to the seal is a good idea.

Thanks for all the help. mc cable is to be used as the wiring method to supply light fixtures in a class I div.2 area. Concerning bonding, if I am correct I'm eventually led to 250.92(B)(2) through (B)(4). As I see threaded hubs referenced , would mc connectors installed into weather proof (bell) boxes be compliant as opposed to 4 inch square boxes with mc connectors and bond bushings ? Thanks again.

 

[rbalex]

Thanks for all the help. mc cable is to be used as the wiring method to supply light fixtures in a class I div.2 area. Concerning bonding, if I am correct I'm eventually led to 250.92(B)(2) through (B)(4). As I see threaded hubs referenced , would mc connectors installed into weather proof (bell) boxes be compliant as opposed to 4 inch square boxes with mc connectors and bond bushings ? Thanks again.

You should be ashamed of yourself, you may recall the context of your question but I had to reread the whole thread.

To answer your question: yes, but make sure the threads ultimately comply with Section 500.8(E).

 

[don_resqcapt19]

No connector with male threads has ever been evaluated by a listing agency for use with female threads. They have only been evaluated for use with locknuts.

 

[rbalex]

No connector with male threads has ever been evaluated by a listing agency for use with female threads. They have only been evaluated for use with locknuts.

It is the opinion of CMP 14 that 5 (or 7 or 4-1/2 in some cases) "wrench tight" is suitable. You know how to make a Public Input or submit an Official Interpretation request to clarify the issue if you so desire. I don't want to open that can of worms. It would take the consensus of, at least, CMP 1, 5 and 14 to close it.

 

[jerryatric]

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It is the opinion of CMP 14 that 5 (or 7 or 4-1/2 in some cases) "wrench tight" is suitable. You know how to make a Public Input or submit an Official Interpretation request to clarify the issue if you so desire. I don't want to open that can of worms. It would take the consensus of, at least, CMP 1, 5 and 14 to close it.

Bob , sorry for the lack of information on my question ; thanks for taking time to answer
Mike

 

[don_resqcapt19]

It is the opinion of CMP 14 that 5 (or 7 or 4-1/2 in some cases) "wrench tight" is suitable. You know how to make a Public Input or submit an Official Interpretation request to clarify the issue if you so desire. I don't want to open that can of worms. It would take the consensus of, at least, CMP 1, 5 and 14 to close it.

No change is necessary. 501.8(E)(1) requires the use of listed cable fittings. No cable fittings that have male threads have been listed for use with fittings that have female threads.

 

[rbalex]

No change is necessary. 501.8(E)(1) requires the use of listed cable fittings. No cable fittings that have male threads have been listed for use with fittings that have female threads.

I believe you meant 500.8(E)(1). Otherwise, you are absolutely right. Of course, that means no cable connector (listed or not) is acceptable in a classified location without an auxiliary bonding connection. In fact, it would mean threaded raceways and ordinary couplings must have auxiliary bonding too per 501.30(A).

Several testing organizations, FM, Intertek (ETL), and UL along with NEMA have two representatives, a principal and an alternate, on CMP14. Several of them are represented on the other CMPs I mentioned earlier as well. Your concern doesn't seem to bother them. Maybe it should, it took UL 25 years to reveal that seals were originally only listed for 25 percent fill. I note the same Subsection, 500.8(E)(1) seems to find 5 wrench-tight threads are suitable. Maybe a Formal Interpretation is in order. I don't intend to write it.