Solar Q: roof J-box
Trying to figure out how to attach small 4x4x2 PVC J-box on the EPDM/plywood roof. There will be a big hole in the bottom, where a pair of #4 cables will go into the trailer. With a hole that big i...
Forum Discussion
wintersun wrote:
Every box I have seen is not fully waterproof when mounted horizontally, even the box from AMsolar.
I've put this statement to test, since it claims to provide protection against "hose-directed water and water entry during prolonged submersion". This is $8 box from Home Depot, with rubber gasket - 1st link in the 1st post. IP code suggests duration from 5 minutes for spraying and 30 minutes for immersion. I'm not that patient. Filled the sink with water, tightened the box lid and held the box under water for 20 seconds. Opened again - not a drop inside. Since my roof will not be "immersed", I can make a plastic or neoprene hood over that lid, in case of some VERY heavy rain storm. So water ingress through the box lid does not worry me.
wintersun wrote:
With my setup I could see that there was 1/2" thick particle board before I made the hole for the cables. I avoideded any kind of gland or nipple as it would have interfered with routing the cables inside the cabinet that was below the box. I did use waterproof glands with the 10-2 cables from the panels.
"Waterproof glands" are probably what they call "strain relief"? I am not an electrician, correct me if I'm wrong, but the glands like Liquidtight (last link in the 1st post) are not waterproof around the cable. They are only waterproof around the end of the conduit - if you use a conduit - and around the J-box wall.
