Did a small job yesterday making a short run of outdoor conduit watertight; homeowner gave me the connectors (elbows and compression fittings) and had me replace the existing ones.
The compression connectors were labeled "concrete tight", and when I asked him if that meant they were truly watertight, he said he was told they were by someone where he bought them (which I think was a big orange store).
So what's the recommended practice to make metal conduit watertight? Yes, I know one can use plastic, but I'm interested in how to make the steel stuff withstand weather.
I have seen wiring failures in outdoor conduit caused by the ingress of water; in one case, a nick in a wire caused by pulling it caused corrosion to the point that the wire actually broke in two.
(This installation is mostly under an eave, so watertightness isn't super-critical, but keeping water out is a Good Thing.)