First residential

[jph320]

This is going to be my first pv system. I would like it to look clean by taking my pv wire into jb. Where it will meet Romex from the attic and them to my ac combiner box. Can't find any section in code book about not being allowed. Egc will still be outside. Any thoughts

 

[GoldDigger]

Your reference to AC combiner box makes it sound like you are using microinverters. If so, why use PV wire outside the array at all?
More info Please!

 

[jph320]

Yes micro inverters. I was referring to the wire from output of inverters to Romex inside outdoor jb on the roof then to my combiner. This roof has 3 different sections so I thought all wiring done inside attic would look neater for customer.

 

[GoldDigger]

OK. So you are using the trunk cable supplied by the inverter manufacturer? And do not want to run that inside?
Technically the inside of a JB mounted on the outside of the roof is a wet area where NM would not be allowed. No idea how your AHJ would view that though.

 

[jph320]

Yes I was referring to the "trunk" cable. I guess I could run it in the attic to combiner instead of transition to Romex or uf. Goal is to eliminate roof conduit all over the place.

 

[jaggedben]

You're probably not going to get enough length on the trunk cable to run it into the attic, so I think your initial idea is on the right track. However, Goldigger is right that using Romex on the roof is not really kosher because that's a wet location.

I'd suggest stubbing EMT through the roof to the J-box, running FMC inside the attic, and pulling properly wet-rated conductors, i.e. TWHN.

Also, other than on the array itself, your EGC should be run with the other conductors.

 

[SolarChuk]

mc cable cannot be used on a roof

mc cable cannot be used on a roof

maybe romex listed for outdoor/sunlight can but wouldnt do it myself. cable that contains same 4 wires as enphase trunk cable available. dependening on how many strings would be deciding issue for where combining occurs. Zilla mount or solardeck or JB depending.

 

[Solar Peep]

Use a soladeck bring circuits into that j box then transition to 3/4" aluminum flex in and through attic.
https://www.platt.com/CutSheets/Select Vendor/rstc-soladeck20specsheet-44099.pdf

 

[SAP]

Romex

Romex

When we do micro inverters we use Romex in the attic, soon has the railing is up and leveled,drill a hole in the roof big enough for 3/4 or 1" EMT, cut the EMT about 6",put a otay roof jack (it has the rubber booty) stick the Conduit threw the hole and the roof jack connect a a 2 gang bell box text screw bell box to side of rail to secure it.from the inside of the attic push your Romex threw the EMT, now your Romex is protected by the EMT.on the roof use a strain relief to go into 2 gang bell box put trunk cable in bell box and wire nut trunk cable to Romex done

 

[jaggedben]

When we do micro inverters we use Romex in the attic, soon has the railing is up and leveled,drill a hole in the roof big enough for 3/4 or 1" EMT, cut the EMT about 6",put a otay roof jack (it has the rubber booty) stick the Conduit threw the hole and the roof jack connect a a 2 gang bell box text screw bell box to side of rail to secure it.from the inside of the attic push your Romex threw the EMT, now your Romex is protected by the EMT.on the roof use a strain relief to go into 2 gang bell box put trunk cable in bell box and wire nut trunk cable to Romex done

I've certainly done this a few times. However, it's good to be aware, strictly speaking, that even the unsheathed romex wires are not supposed to be in a wet location such as a rooftop junction box.

 

[jph320]

Thanks for all the input. Also is rooftop disco required. Here in phila we are still using the 08 code book.

 

[SolarPro]

Enphase white paper to the rescue:

Connectors as AC Disconnects in PV Applications

 

[GoldDigger]

Enphase white paper to the rescue:

Connectors as AC Disconnects in PV Applications

I am not satisfied with their interpretation of "identified for the use."
I agree that "listed" as applied to a normally "recognized" component is problematic. But most of the connector types that a field electrician normally encounters would in fact be "listed". (E.g. NEMA connectors).

My take is that only "recognized" connectors with the reverse RU marking would not in fact meet the code requirement.
NEMA connectors, on the other hand, are generally rated for load breaking, yes?

 

[SolarPro]

Here's text from the Expedited Permit Process for PV Systems report published by the Solar America Board of Codes and Standards (see Annex C on microinverters):

Disconnecting Means

Since most micro-inverters are mounted in locations that are not readily accessible (e.g.
sloped rooftops), then we must review the requirements of 690.14 (D) Utility-Interactive
Inverters Mounted in Not-Readily-Accessible Locations.

This provision specifically allows micro-inverters to be installed in places that are not
readily accessible like rooftops. In order to meet the requirements, the micro-inverter
must have dc and ac disconnects in sight of the inverter. These disconnects would also
be in a not-readily accessible locations so 690.14(D)(3) requires that an additional ac
disconnect be in a readily accessible location. This provision can be met as simply as a
circuit breaker at the ac point of connection in the main service panel on a house. Lastly,
690.14(D)(4) requires that a sign be placed at the service entrance notifying where the
inverters are located on the premises. The cited article 705.10 allows large numbers of
inverters to be identified in groups rather than individually.

690.14(D) begs the question as to whether disconnects now have to be mounted with
the micro-inverters. Bulky, vertically mounted disconnects would clearly make microinverters
impractical. However, the exception at the end of 690.17 clarifies that a
connector may be used as a disconnect provided the connector meets the requirements
of 690.33 and is identified for the application. All the requirements in 690.33 apply, but
the most specific relates to interruption of the circuit, 690.33(E).

690.33(E) Interruption of Circuit. Connectors shall be either (1) or (2): (1) Be rated for
interrupting current without hazard to the operator. (2) Be a type that requires the use of a
tool to open and marked “Do Not Disconnect Under Load” or “Not for Current Interrupting.”

Some micro-inverter manufacturers have their connectors certified as capable of
interrupting maximum current without hazard to the operator. Those that do not have
this certification must have connectors that require a tool along with the required
marking to prevent inadvertent disconnect under load.