nema 12 enclosure modification

[lowvoltman]

Can a nema type 12 enclosure be modified by drilling drain holes in the bottom to nema 3r? I've seen this stated before but would like to find some documentation that states that.
thanks!

 

[jim dungar]

Can a nema type 12 enclosure be modified by drilling drain holes in the bottom to nema 3r? I've seen this stated before but would like to find some documentation that states that.
thanks!

There is more to a NEMA 3R than simply drain holes in a NEMA 12. For example, a NEMA 3R enclosure must have provisions to prevent water from puddling on the upper door trim gasket.

There are so many companies that make NEMA 12 enclosures which may be field modified to NEMA 3R, that many people assume this is a standard modification. Check with your manufacturer.

 

[pfalcon]

From NEMA 250:2008 Brief on the NEMA.org website

This standard does not cover the requirements for protection of devices against conditions such as condensation, icing, corrosion, or contamination which may occur within the enclosure or which may enter via conduit or unsealed openings.

So drilling holes in the bottom doesn't change the enclosure rating. The holes you drill are not covered by the NEMA standard. Therefore drilling holes in the bottom of a NEMA 12 makes it a NEMA 12 with holes drilled in the bottom.