D/C conduit interpretation

[Liquidoutl4w]

So looking at the code on dc conduit it says must be metal when entering the interior of the structure, now when you look at that the interior wouldn't count the soffit to roof (closed eve) as it's not the interior, now how does an open eve weigh in all that. Am I wrong with my interpretation (see photo) that the red outline is considered the interior space?

 

[ggunn]

So looking at the code on dc conduit it says must be metal when entering the interior of the structure, now when you look at that the interior wouldn't count the soffit to roof (closed eve) as it's not the interior, now how does an open eve weigh in all that. Am I wrong with my interpretation (see photo) that the red outline is considered the interior space?

If you are asking if inside a closed eave is considered to be inside the building, I believe that most inspectors would say yes.

 

[jaggedben]

Honestly I'd probably frown on using anything besides EMT in that location anyway.

 

[paullmullen]

I have a ground-mounted application. So from the solar array to the house underground, I anticipate PVC. The inverter/batteries will be in the garage. Where do you make the transition from PVC to EMT? Any thoughts on PVC vs Liquitight?

 

[ggunn]

I have a ground-mounted application. So from the solar array to the house underground, I anticipate PVC. The inverter/batteries will be in the garage. Where do you make the transition from PVC to EMT? Any thoughts on PVC vs Liquitight?

I assume that you will come out of the ground next to the garage and then enter through the wall. PVC (not liquidtight) UG, transition to a junction box on the garage wall, and EMT out the back of the box into the garage, maybe?

 

[Zee]

I learned 20 years ago not to use PVC on a roof - whether or not it is allowed by the NEC.
EMT 100% for decades.

PVC shrinks and tears out of glued fittings. Exposing wires. (3x higher heat coefficient of expansion)
PVC expands and then sags and looks cheap and flimsy.
It becomes brittle and can shatter easily.

You realize you can use EMT? Unless NY is different....... rigid conduit may not be required.
EMT is light, cheap and easy to install.

 

[pv_n00b]

The only place I can see PVC making sense on the roof is somewhere like Hawaii. It still has all the PVC problems, but the alternatives in metal are just worse.

 

[ggunn]

The only place I can see PVC making sense on the roof is somewhere like Hawaii. It still has all the PVC problems, but the alternatives in metal are just worse.

The company I recently retired from had a policy of using PVC on any rooftops within 20 miles of a body of salt water.

 

[jaggedben]

The company I recently retired from had a policy of using PVC on any rooftops within 20 miles of a body of salt water.

20 miles is ludicrous. That would wrap up the entirety of my career of thousands of rooftop EMT installations with no issues.

Half a mile would be reasonable. But a better approach would probably be to paint conduit or perhaps use aluminum.

 

[pv_n00b]

20 miles is ludicrous. That would wrap up the entirety of my career of thousands of rooftop EMT installations with no issues.

Half a mile would be reasonable. But a better approach would probably be to paint conduit or perhaps use aluminum.

Depends on where you are since the temperature, wind, etc. are variables. In NorCal it's not as big an issue. In the islands, the gulf coast, or Florida the salt travels farther. I've seen EMT outside in Hawaii, it rots pretty quickly. PVC might be a sagging scribble on the roof but it's still intact.

 

[ggunn]

Depends on where you are since the temperature, wind, etc. are variables. In NorCal it's not as big an issue. In the islands, the gulf coast, or Florida the salt travels farther. I've seen EMT outside in Hawaii, it rots pretty quickly. PVC might be a sagging scribble on the roof but it's still intact.

FWIW, the systems affected by the company policy were all in Florida and on the Texas Gulf Coast.

 

[Zee]

yeah different in CA, 1/2 mile and metal is fine. must be air currents or humidity (lack thereof)?

 

[Zee]

put a lot of extra bends in that PVC! It's gonna push and pull, shrink and expand a lot.