NEMA rating for damp locations

[NVAP]

Hello,

We have a use case to install an AC powered device in a location that is covered with a roof and walls on three sides (front is open). The device in this installation will be exposed to moisture and potentially some water contact from wind driven rain. This location will be defined as "damp" by NEC.

Is NEMA12 sufficient for such locations or do they need to be NEMA4?

 

[petersonra]

Hello,

We have a use case to install an AC powered device in a location that is covered with a roof and walls on three sides (front is open). The device in this installation will be exposed to moisture and potentially some water contact from wind driven rain. This location will be defined as "damp" by NEC.

Is NEMA12 sufficient for such locations or do they need to be NEMA4?

The reality is that it will work just fine. However it is not listed for such locations. Personally I would get a type 3r enclosure rather than a type 4. The type 3r has holes in the box so it can drain and if you get a type 4 box there is a good chance you will get condensation inside that has no where to drain.

 

[Fred B]

Why are you suggesting NEMA 12? Listing does not suggest use for driven rain or hose down, only suggests moderate protection from dripping water. Does enviroment have issues that would cause dust and fiber dust intrusions issue in an indoors application? That is where NEMA 12 is primarily used. Otherwise a simple NEMA 3r would be adequate and cost way less. If fibrous dust a concern a NEMA 4 would be adequate and provide protection for driving rain or hose down and still less costly that the NEMA 12

 

[retirede]

The reality is that it will work just fine. However it is not listed for such locations. Personally I would get a type 3r enclosure rather than a type 4. The type 3r has holes in the box so it can drain and if you get a type 4 box there is a good chance you will get condensation inside that has no where to drain.

And I think Hoffman used to state that their N12 enclosures could be used as 3R by adding a drain. I don’t know if that’s still true for any manufacturers.

 

[petersonra]

And I think Hoffman used to state that their N12 enclosures could be used as 3R by adding a drain. I don’t know if that’s still true for any manufacturers.

At least some of the type 12 hoffman boxes could be converted to type 3R by adding drain holes and a rain shield above the door gasket at the top of the door.