Standing seam roof penetration

[btrocke]

I’ve done quite a few asphalt shingle installations with rails but this is my first standing seam installation. The roof on the garage was fairly old so before installing solar we put on a brand new standing seam roof. We are using S-5! Mounts with the panels in a landscape orientation so no rails. The roof is E/W facing and we will have 3 strings on each side for a total of 6 strings 32kw. My biggest question is, what’s the best way to run the PV wire to the inverters? Since there are 3 strings on each side, I’d ideally like to do a roof penetration with a junction box near the ridge on each side to transition to THHN wire. I’m okay with going around the overhang/soffit but can’t think of a clean way of doing it. Any thoughts on best practice here?

 

[BerndL]

I'd actually like to hear from people why they'd suggest a roof penetration at all. I avoid them like the plague and run conduit to a wall penetration.

 

[fuzzmunky415]

Yep, go around eave in a non-conspicuous area.

 

[timselectric]

It's easier to install with the roof.
But it can be done as a retro fit.

 

[btrocke]

Yep, go around eave in a non-conspicuous area.

That's ideally what I would like to do, but I’m having a hard time figuring out where and how to transition from PV wire to THHN since there are no rails I can’t just mount a junction box to a rail.

 

[chill633]

That's ideally what I would like to do, but I’m having a hard time figuring out where and how to transition from PV wire to THHN since there are no rails I can’t just mount a junction box to a rail.

Are you running the PV wire in conduit on your roof? I'm doing EMT on the roof, transitioning to LFMC over the eave and then to PVC down the side. The roof conduit is supported using S-5 Canduit clamps. Mount the box to the wall, under the eave.

Or just throw money at it and don't transition. One long run of unbroken solar wire.

 

[Verbs]

I ran conduit up the roof and in the ridge.

You can see the conduit prepped here. Ignore all the wires running exposed temporarily while working on conduit.




An after photo, again, ignore the temporary free wires while I worked on getting conduit for those.

 

[chill633]

I wanted to avoid having to derate any of the wires because they're close to the roof. They have to be a certain distance above otherwise the extra heat reflected from the roof requires derating according to the NEC. By using the Canduit it raises the conduit a full 4 to 6 in above the roof and heat isn't a problem.

You could always just add a mini rail right there and mount a box to that. Check out the S-5 Gripperfix, which is under their utility mounting solutions. It is used to mount boxes and satellite dishes to standing seam.

 

[dopeassjackson]

Out the peak/ridge flashing is how mine is. Since you have standing seam roofing I would buy standing seam clamps and have Zero roof penetrations.

 

[Verbs]

I wanted to avoid having to derate any of the wires because they're close to the roof. They have to be a certain distance above otherwise the extra heat reflected from the roof requires derating according to the NEC. By using the Canduit it raises the conduit a full 4 to 6 in above the roof and heat isn't a problem.

You could always just add a mini rail right there and mount a box to that. Check out the S-5 Gripperfix, which is under their utility mounting solutions. It is used to mount boxes and satellite dishes to standing seam.

Heh, the solar panels that are too hot to touch have the wires zip tied to them, and that's fine, but the white roof that I can sit on when it's 105° outside, that's too hot for wires to be close to?

The NEC got that one wrong.

 

[timselectric]

Heh, the solar panels that are too hot to touch have the wires zip tied to them, and that's fine, but the white roof that I can sit on when it's 105° outside, that's too hot for wires to be close to?

The NEC got that one wrong.

It's the type of conductor (insulation) and the fact that it's inside conduit that makes the difference. It's all about the ability to shed the heat away.

 

[btrocke]

I ran conduit up the roof and in the ridge.

You can see the conduit prepped here. Ignore all the wires running exposed temporarily while working on conduit.

View attachment 344176


An after photo, again, ignore the temporary free wires while I worked on getting conduit for those.
View attachment 344177

Awesome pictures. Exactly what I was looking for. Did you put any sort of connector on the ends of the conduit?

 

[Verbs]

I put a ziptie to hold the wire together just inside the end of the conduit and help ensure the wire insulation wasn't touching the conduit, and then some silicon caulk to seal it.

 

[fuzzmunky415]

I put a ziptie to hold the wire together just inside the end of the conduit and help ensure the wire insulation wasn't touching the conduit, and then some silicon caulk to seal it.

Was there a reason to not use a jbox or similar? Prolly another failure point?

 

[Verbs]

The junction box is just inside the ridge. I just needed a simple piece of conduit to protect the wires up and through the ridge vent. A jbox usually has a hole going down into the roof. My install method has zero through the roof holes, at least none for the solar system.