DC wiring / conduit within a building

[heimdm]

I was reviewing NEC code requiring the dc wiring once it enters the building since my inverters are going in a detached garage.

The code states:
690.31(G) Photovoltaic System Direct Current Circuits on or in a Building. Where PV system dc circuits run inside a building, they shall be contained in metal raceways, Type MC metal-clad cable that complies with 250.118(10), or metal enclosures from the point of penetration of the surface of the building to the first readily accessible disconnecting means. The disconnecting means shall comply with 690.13(B) and (C) and 690.15(A) and (B). The wiring methods shall comply with the additional installation requirements in 690.31(G)(1) through (4).

If I am reading correctly, does this mean once the pv wires go through the exterior walls, everything needs to be in metal race (rigid metal conduit [rmc], electrical metal tubing [rmt], or flexible metal-clad cable, until it reaches the inverter. In my setup the wires will enter, then hit fuses, then make their way to the inverter.

[PVAndy]

I was reviewing NEC code requiring the dc wiring once it enters the building since my inverters are going in a detached garage.

The code states:
690.31(G) Photovoltaic System Direct Current Circuits on or in a Building. Where PV system dc circuits run inside a building, they shall be contained in metal raceways, Type MC metal-clad cable that complies with 250.118(10), or metal enclosures from the point of penetration of the surface of the building to the first readily accessible disconnecting means. The disconnecting means shall comply with 690.13(B) and (C) and 690.15(A) and (B). The wiring methods shall comply with the additional installation requirements in 690.31(G)(1) through (4).

If I am reading correctly, does this mean once the pv wires go through the exterior walls, everything needs to be in metal race (rigid metal conduit [rmc], electrical metal tubing [rmt], or flexible metal-clad cable, until it reaches the inverter. In my setup the wires will enter, then hit fuses, then make their way to the inverter.

Yes, typically we use EMT or MC, We only use RMC where required by local code (New York City)

Andy

[solarix]

Technically, the fuses (I assume a DC combiner) is serving as the disconnecting means for the array should be on the roof within sight of the array so that whoever is working on the array has the assurance it is off.

[heimdm]

Technically, the fuses (I assume a DC combiner) is serving as the disconnecting means for the array should be on the roof within sight of the array so that whoever is working on the array has the assurance it is off.

It's a solar edge setup, with dc optimizers. Technically per SE, fusing isn't required. However, all the articles I have seen is that is based on their testing, and some AHJ don't accept it. My thought was to do an enclosure that has lightening protection, and the fuses in it, located in the building. My plan at the moment is to run PV wire from the array into the building, and hit that fuse/combiner box. Since I will have the detached garage which is protected from the elements, the idea was to put any of the stuff that I can in there.


This is all going on a standalone pergola, with a detached garage next to it. I am hoping to have the detached garage completed by the end of summer.

Last year, we had an indirect lightening strike that turned the aluminum fence into a conductor and made a mess of electronics in the house.

From a wiring perspective, do you usually leave it as PV wire all the way to the inverter or do you switch to something like THHN/THWN?

[oregon_phil]

I used the Southwire conduit fill calculator to find out if an additional 600VDC ethernet cable could be pulled in the existing EMT for Tigo installation. This was verified by the electrician. Running the conduit fill calculator for PV wire and THWN for the quantity and wire diameter might help you make a decision. My SMA installation transitions from PV to THWN in a box on the roof.

[heimdm]

If I stay with PV wire, it would take close to a 2" conduit, while THWN/THHN is about 1 1/4. I want to plan everything, but I really just have to wait and see how the detached garage and solar pergola turns out. I know how it should be, but who knows. I am guessing, I will end up finding a way to put a junction box up there, and using that as an opportunity move all the wires into conduit.

[peakbagger]

Soladeck boxes are a nice option for roof mounted box. I modified mine to add in Midnight Solar SPD hanging out the bottom with 45 degree elbow

[PVAndy]

Technically, the fuses (I assume a DC combiner) is serving as the disconnecting means for the array should be on the roof within sight of the array so that whoever is working on the array has the assurance it is off.

MC4 connectors are listed as no load break DC disconnects

Andy

[jacknj]

Yes, typically we use EMT or MC, We only use RMC where required by local code (New York City)

Andy

Could you please clarify the following?
1. Can you use PVC through the exterior wall and then start with EMT inside the building/basement?
Is it a topic where the local inspector might have a specific point of view?
2. Does the EMT conduit going to the inverter needs to be bonded?

Thanks.

[Ampster]

.....
Does the EMT conduit going to the inverter needs to be bonded?
.

I am sure the code will vary but installers on two of my systems in different jurisdictions in California used bonding devices to bond the EMT jto ground. In this case they were typically bushings that screwed onto the connector inside the point where the wires entered the inverter. Those bushings had a ground connector screwed to the bushing.

[jacknj]

I am sure the code will vary but installers on two of my systems in different jurisdictions in California used bonding devices to bond the EMT jto ground. In this case they were typically bushings that screwed onto the connector inside the point where the wires entered the inverter. Those bushings had a ground connector screwed to the bushing.

Thank you for your answer.

Am I assuming correctly that the ground connector of the bushing would be connected to the inverter groundung terminal?

[Ampster]

......
Am I assuming correctly that the ground connector of the bushing would be connected to the inverter groundung terminal?

Yes