Class1, Div 1 whip

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jazzman

Member
One of my customers is a large auto dealer with a paint shop on the premises. His insurance agent visited and saw a whip on the motor for the paint mixer (equipment that holds about 50 different cans of paint and auto mixes them for desired color). The existing whip looks like 3/8" black seal tite. He said that it does not meet the requirements for a Class 1 Div 1 location. The existing whip enters the back of a 20 amp twist lock plug which plugs into an explosion proof receptacle. What would be the correct way of connecting this piece of equipment?
 

sgunsel

Senior Member
Is the paint mixer located in a Class I, Division 1 area? Or maybe in a Class I, Division 2 area? Or is it in an unclassified area? See NEC Article 516 or NFPA 33, Standard for Spray Application Using Flammable or Combustible Materials, Chapter 6, to determine the classified areas in and around a spray booth or spray room.
 

jazzman

Member
Thanks for your response sgunsel. I guess I asked the wrong question. It does not matter whether the insurance agent is correct or not in defining this area. He wants an explosion proof flexible whip to connect this motor to the twist-lock plug. Does such a conduit exist?
 

Smart $

Esteemed Member
Location
Ohio
One of my customers is a large auto dealer with a paint shop on the premises. His insurance agent visited and saw a whip on the motor for the paint mixer (equipment that holds about 50 different cans of paint and auto mixes them for desired color). The existing whip looks like 3/8" black seal tite. He said that it does not meet the requirements for a Class 1 Div 1 location. The existing whip enters the back of a 20 amp twist lock plug which plugs into an explosion proof receptacle. What would be the correct way of connecting this piece of equipment?
The first question is whether the flexible connection is required?

If not, then it has to be hardwired using one of the wiring methods mentioned in 501.10(A)(1). Two of those are not viable being it is not an inductrial application, so options a and b are the only two viable: RMC, IMC, or MI-cable.

If flexible connection is required, refer to 501.10(A)(2) and therefrom 501.140... noting the requirements for whether a flexible cord/cable is permitted (which I do not believe the item of discussion qualifies).
 

sgunsel

Senior Member
I would detemine the correct classification and explain that to the insurance person. They Are usually not inflexible if you can support your position. Very few are knowledgeable about classified areas and will welcome any clarification you can provide. No need to roll over and accept a bad call - if it is one. He may be right.
 
The first question is whether the flexible connection is required?

If not, then it has to be hardwired using one of the wiring methods mentioned in 501.10(A)(1). Two of those are not viable being it is not an inductrial application, so options a and b are the only two viable: RMC, IMC, or MI-cable.

If flexible connection is required, refer to 501.10(A)(2) and there from 501.140... noting the requirements for whether a flexible cord/cable is permitted (which I do not believe the item of discussion qualifies).

The OP almost sounded exactly like the example that is given in 140.:

501.140 Flexible Cords, Class I, Divisions 1 and 2.
(A) Permitted Uses.​
Flexible cord shall be permitted:

.........

(4) For electric mixers intended for travel into and out of

open-type mixing tanks or vats.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Thanks for your response sgunsel. I guess I asked the wrong question. It does not matter whether the insurance agent is correct or not in defining this area. He wants an explosion proof flexible whip to connect this motor to the twist-lock plug. Does such a conduit exist?
Without addressing the specifics of whether or not it is needed because as you say, he wants it even if it isn't, the answer is, yes. Here is an example:

Class 1 Div. 1 rated portable cord

But note there are specifics as to which parts of the code allow its use, so you really still come back to what the others have said; do you or don't you need it?
 

sgunsel

Senior Member
We need more information. Is the mixing device portable or not? With 50 cans (1 ounce each or 1 gallon or ?) it doesn't sound like it is portable. What are the manufacturer's recommendations? Take a good look at NEC 500 and 501.

The interior of a spray booth is a Class I, Division 1 area. I have not seen color mixers installed in a spray booth. Usually the booth is too small and overspray would be a real issue. If it is located inside the spray booth, the "mixer" itself must be listed for Class I, Division 1 and hard wired, unless it is a portable device that is moved in for mixing, then removed.

If it is outside the spray booth and more than 3 feet from any spray booth doors, the area is most likely unclassified. Depending on the design of the mixing device, however, it may or may not create a classified area.
 
We need more information. Is the mixing device portable or not? With 50 cans (1 ounce each or 1 gallon or ?) it doesn't sound like it is portable. What are the manufacturer's recommendations? Take a good look at NEC 500 and 501.

Portability of the agitator is not necessarily the requirement. The agitator may be mounted in a permannent place, but movement of it is required.

If they are mixing paint in small - or large - containers and they move the containers under the agitator, which needs to be lowered into the container then flexibility is required.

The NEC has a provision for just the above.
 

Smart $

Esteemed Member
Location
Ohio
Portability of the agitator is not necessarily the requirement. The agitator may be mounted in a permannent place, but movement of it is required.

If they are mixing paint in small - or large - containers and they move the containers under the agitator, which needs to be lowered into the container then flexibility is required.

The NEC has a provision for just the above.
Yes, if for the agitator/motor assembly.

But if this is to supply power to a framework and/or control enclosure of the "mixer" which does not move regularly, essentially fixed in place, such would not qualify.
 
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