I had a contractor come by my house recently to do AC maintenance for the unit located on my roof. While up there, he mentioned that the conduit pipes that carry the electrical wires were not rated for exterior use and could create problems at the joints. A solution he proposed was to take some silicone caulking and just cover the joints to help prevent water from getting into the pipe.
Does it matter what type of caulking I get, should I just look for a product that is 100% silicon and call it a day, or is there another type of sealant that I should look for?
I would prefer not to have to replace the conduit piping since there is a lot up there (there are 5 other units in my building) and prefer a DIY solution that will help mitigate any problems until ALL of the conduit on the roof can be replaced.
Here are pictures of the joints I am talking about: http://imgur.com/a/xYhhR