A drain hole will equalise the pressure inside and outside of the enclosure, so moisture won’t be “pumped” through the cables.
I am a great believer in small drain holes at the bottom of outside equipment like lights, sockets, switches, P.I.R. sensors or adaptable boxes. Also I try to ensure that all cables only enter at the bottom of enclosures. The holes that I drill are very small, usually less than 1.0mm in diameter. But we must be aware that if the hole is too small it may become blocked by dirt, dust or dead insect bodies. Some outdoor weatherproof accessories have the provision for drainage of water by a drain hole in their boxes and the position is marked inside boxes and have to be drilled out. I also like to provide drainage holes at the lowest points in external conduit at boxes and accessories. This prevent the build up of condensation and aids drainage.
A drain hole will equalise the pressure inside and outside of the enclosure, so moisture won’t be “pumped” through the cables.
I am a great believer in small drain holes at the bottom of outside equipment like lights, sockets, switches, P.I.R. sensors or adaptable boxes. Also I try to ensure that all cables only enter at the bottom of enclosures. The holes that I drill are very small, usually less than 1.0mm in diameter. But we must be aware that if the hole is too small it may become blocked by dirt, dust or dead insect bodies. Some outdoor weatherproof accessories have the provision for drainage of water by a drain hole in their boxes and the position is marked inside boxes and have to be drilled out. I also like to provide drainage holes at the lowest points in external conduit at boxes and accessories. This prevent the build up of condensation and aids drainage.
