Class 1 Div 2 Methods

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tkb

tkb

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Location
MA
I have a job installing some VFD's for motors in a sewage treatment plant.
The room is Class 1 Div 2.
The motors are connected with AL conduit drooping from the ceiling to a gasketed malleable tee with a nipple to a floor flange for support. and LFMC to the motor.
The motor is an explosion proof motor.

We want to cut the conduits in the ceiling and install conduits to another room where the VFD's will be located. Seals at the boundaries.
We will be installing new conduits for three drops to the motors because of corrosion.

Questions,
  1. Can we install gasketed screw cover junction boxes and myers hubs in the ceiling of a CL1 Div2 area or do they have to be explosion proof?
  2. Can we use LFMC from a gasketed malleable LB at the motor? We will not be using the tee and floor flange method, we will be building a strut support.
I have looked in atricle 510.10(B) and believe these methods are allowed. But I was wrong once.
 
  1. Nothing can be between the seal and the boundary.[501.15(B)(2)]
  2. LFMC is fine.
The motors probably don't need to be explosionproof,[501.125(B)] but even explosionproof motors should be rated for VFD duty in a hazardous location per NEMA MG-1. That makes it a 110.3(B) issue.
 
tkb said:
I have a job installing some VFD's for motors in a sewage treatment plant.
The room is Class 1 Div 2.
The motors are connected with AL conduit drooping from the ceiling to a gasketed malleable tee with a nipple to a floor flange for support. and LFMC to the motor.
The motor is an explosion proof motor.

We want to cut the conduits in the ceiling and install conduits to another room where the VFD's will be located. Seals at the boundaries.
We will be installing new conduits for three drops to the motors because of corrosion.

Questions,
  1. Can we install gasketed screw cover junction boxes and myers hubs in the ceiling of a CL1 Div2 area or do they have to be explosion proof?
  2. Can we use LFMC from a gasketed malleable LB at the motor? We will not be using the tee and floor flange method, we will be building a strut support.
I have looked in atricle 510.10(B) and believe these methods are allowed. But I was wrong once.
Click to expand...



Hate to reply with a question Is the box listed for Class I Div. II?
 
Last edited:
rbalex said:
  1. Nothing can be between the seal and the boundary.[501.15(B)(2)]
  2. LFMC is fine.
The motors probably don't need to be explosionproof,[501.125(B)] but even explosionproof motors should be rated for VFD duty in a hazardous location per NEMA MG-1. That makes it a 110.3(B) issue.
Click to expand...

The motor does need to be listed for Class I Div II because it produces heat.
 
dkeaux@gmail.com said:
You can use that box for that purpose I would recommend SS if it's a corrosive area without it being listed for ClaSI DivII,
it falls into the catagory of general equipment.
Click to expand...
What equipment, besides luminaires, need to be specifically listed for Class I, Division 2? See 500.8 (C) [general] and 500.8(C)(6)(a) [specific]
 
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