TEFC motors (non-explosionproof) installation in a Class 1 Div 2 hazardous area where with general purpose enclosures are used for connecting the motor leads to the power supply, can you just drill some small holes in the bottom of enclosure to facilitate draining the box of moisture/condensate buildup (terminal box has top conduit entry, so box is low point) or are you required to use an approved breather/drain i.e. Crouse Hinds ECD18. Seems to me, since it is general purpose enclosure with no arcing devices, small holes i.e. 3/16" would be acceptable? Thoughts?
Motor Terminal Box Drains in Class 1 Div 2 Area
- Thread starter feyme
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Re: Motor Terminal Box Drains in Class 1 Div 2 Area
Any modification to enclosures done in the field will void the UL listing unless done according to UL directions. However, not all locations require listed enclosures (314.15(A) requires listed boxes for wet locations, and 314.27(C) requires a listing for floor boxes, there may be others).
That said, the inspector would be within his rights to say that a listed box is approved for installation if installed according to its instructions, but he might reject any modifications he thought were excessive or destructive.
Drains required because of moisture buildup in the conduit might be found in boxes designed for the purpose, and require no field modification. A general purpose box is full of small holes, and no moisture will accumulate. Are you installing boxes that are sealed? Maybe they are not right for this application?
Earl
Any modification to enclosures done in the field will void the UL listing unless done according to UL directions. However, not all locations require listed enclosures (314.15(A) requires listed boxes for wet locations, and 314.27(C) requires a listing for floor boxes, there may be others).
That said, the inspector would be within his rights to say that a listed box is approved for installation if installed according to its instructions, but he might reject any modifications he thought were excessive or destructive.
Drains required because of moisture buildup in the conduit might be found in boxes designed for the purpose, and require no field modification. A general purpose box is full of small holes, and no moisture will accumulate. Are you installing boxes that are sealed? Maybe they are not right for this application?
Earl
Re: Motor Terminal Box Drains in Class 1 Div 2 Area
Typically the motors in question are those purchased using IEEE STD 841 Severe Duty TEFC motors up to 500 hp. The standard specifies that the terminal boxes should meet IP55. These boxes are typically of cast iron construction / diagonally split. In the 841 standard it states that for motors above 600v or for frame sizes exceeding 445T at 600V shall be provided with a corrosion-resistant, replaceable automatic drainage fitting. I would just like to drill some small holes without violating the spirit of NEC, since these enclosures did not have a drain fitting to begin with.
Typically the motors in question are those purchased using IEEE STD 841 Severe Duty TEFC motors up to 500 hp. The standard specifies that the terminal boxes should meet IP55. These boxes are typically of cast iron construction / diagonally split. In the 841 standard it states that for motors above 600v or for frame sizes exceeding 445T at 600V shall be provided with a corrosion-resistant, replaceable automatic drainage fitting. I would just like to drill some small holes without violating the spirit of NEC, since these enclosures did not have a drain fitting to begin with.
Re: Motor Terminal Box Drains in Class 1 Div 2 Area
Sounds to me like the manufacturer has supplied instructions to deal with the drainage problem. It may be expensive to provide these drains, but the only justifiable way to acomplish this is to pay the piper. Not to say that if you do drill the holes, every thing won't function just fine for the life of the installation. I have seen much worse function for decades. But, if something does go wrong, some smart-a__ lawyer could determine who violated the manufaturer's instructions, and willfully so, and there goes your retirement. Is it worth it to you to make the gamble? What are the risks?
Earl
Sounds to me like the manufacturer has supplied instructions to deal with the drainage problem. It may be expensive to provide these drains, but the only justifiable way to acomplish this is to pay the piper. Not to say that if you do drill the holes, every thing won't function just fine for the life of the installation. I have seen much worse function for decades. But, if something does go wrong, some smart-a__ lawyer could determine who violated the manufaturer's instructions, and willfully so, and there goes your retirement. Is it worth it to you to make the gamble? What are the risks?
Earl
- Location
- Illinois
- Occupation
- retired electrician
Re: Motor Terminal Box Drains in Class 1 Div 2 Area
Why can't you flip the motor connection box so that the conduit entry is on the bottom and put a drain in the conduit system. I always avoid any top entries if at all possible. Another method that I have seen used is a notch was cut into the junction box gasket on the bottom, however this has the same issues as the ones brought up by Earl for drilling holes in the enclosure.
Don
Why can't you flip the motor connection box so that the conduit entry is on the bottom and put a drain in the conduit system. I always avoid any top entries if at all possible. Another method that I have seen used is a notch was cut into the junction box gasket on the bottom, however this has the same issues as the ones brought up by Earl for drilling holes in the enclosure.
Don
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