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Posted By Topic: Solar systems - roof penetrations

Apr 28 2018 16:13

Hey guys, got a query, currently installing my first solar system and wanting to get some thoughts on roof penetrations. Best case would be to drill under the soffit, add conduit box and flex onto roof and then run cable along, ugly as shit! But then you cant get water into the hole.

I am thinking about using a flashing, right next to panels, run conduit through flashing, add a bend and then flex under panels for and of course load up the flashing with silicon etc.

Just wondering, has anyone had issues with flashing directly through the roof or anyone have any better recommendations? The roof is corrugated iron. Cheers

Apr 28 2018 16:33

On solar systems I have done I have come across variety of iron profiles, where I can I have used a 16mm cable gland on the double insulated single conductor on the high part of the rib and typically make the penetrations under the panels - I have had no leaking issues, have seen multiple ways some pretty some not so.
I have found it depends on how one can run the HD conduits to underside etc, everyone seems to be quite different

Apr 28 2018 16:39

Cheers Sparky59,

The problem i have, i brought all pre MC4 connected cables(had to run all cable in 32mm conduit due to this) and so the 16mm2 tight gland sounds great but unless i cut the connectors off and order some more, trying to figure out best option with what i have, but yeah. Maybe cutting them is an option

Apr 28 2018 17:27

unless you use an approved system, you may have issues when a building inspector next visits the property, personally I use a dektite flashing or similar 3m and bring the HD conduit through it underneath a solar panel, then 2 90deg bends to stop water egress. I\'ve had no issues with leaks or building inspectors.


Apr 28 2018 17:34


Apr 28 2018 17:35

Conduit through the Dektite of course, not just the cables. As Dlink said.

Apr 28 2018 20:33

Cheers guys. Will give that ago. Always risky drilling a hole in a roof. I brought a roof flasing from JA that i thought of using that looks similar but obviously, from your guys experience, better to use the recommended

Apr 28 2018 21:33

When installing the dektite make sure the corners point up and down the slope of the roof so that there is no horizontal lip for water and debris to build up behind, the same can be said for anything else you attach to the roof, watch you don\'t create a dam. Have used them on both residential and commercial roofs and never had one leak yet.

Apr 29 2018 19:51

get some formal training dude !

Apr 29 2018 21:07

Well ive read most of 5033, completed the wiring and installation of the inverter, panels, batteries etc. Once completed it does become pretty straight forwed. Just a few things i thought i would double check, always a worry when drilling into a roof.

The other problem is actually finding some type of training course etc in NZ. Plenty in aussie .