Looking for final blessings: Schematics for Review

[Old_Skewler]

Here is my final design for my off-grid cabin PV installation. I would appreciate any last minute feedback or blessings from the group:










I am comfortable with most of the design but a bit reluctant about the DC disconnect switch rated at 32A. I think I should've bought a higher current switch but i don't know how to gauge whether this should be of concern when Isc=27A.

I also do not know whether combined array wiring should be AWG 8 or 10: different tables show different currents. This would be for a 100 feet total run.

Lastly, the EMT conduit hardware turned out more complicated than I expected after a visit to Lowes: it is not clear to me what is water-tight or not and I suspect since this will go on the roof that need to be water-tight? For instance, they have two options for 3/4" LB boxes, but one is threaded and the other has set screws. Are any of these water tight? The EMT conduit they sell at Lowes does not have threads hence my confusion. Am I supposed to thread these conduits?



Thanks in advance for any feedback or blessings!

 

[Old_Skewler]

I was able to find "rain tight" compression coupling and compression connectors for EMT at Lowes:




But I have not been able to find "rain tight" EMT 90* Compression Connectors. Should there be rain tight versions for these compression connectors or maybe this is not applicable to 90* bends?




Should I be able to find all EMT fittings in "rain tight" version or only a few of the items?

 

[rodrick]

The threaded lb is outdoor rated with the proper fittings used with it, make sure the gasket comes with it

 

[Old_Skewler]

The threaded lb is outdoor rated with the proper fittings used with it, make sure the gasket comes with it

But how to use the EMT with the threaded LB when the emt doesn't have a thread?

How is this connection actually done?

 

[rodrick]

use a fitting like you showed in previous post compression with male threads they will screw into lb

 

[pvgirl]

This system does not appear to by compliant to NEC, at least the 2017 version which seems to be the version for new york state(no rapid shutdown, arc fault or ground fault protection are the most obvious issues). Have you confirmed the requirements for permitting in your cabin's location?

 

[Old_Skewler]

use a fitting like you showed in previous post compression with male threads they will screw into lb

I see it... I didnt realize the thread from the compression connector would match the thread in the LB box.

Thanks!

 

[Old_Skewler]

no rapid shutdown

Doesn't the IMO DC switch satisfies this requirement?

arc fault

Does the SPD cover this requirement? Voltage Surge Arrester Device, 2P Surge Protective Device DC Photovoltaic Lightning Protector Low-Voltage Arrester 3.0KV (2P40KA)

or ground fault protection

What would entail this? And would the Victron MPPT offer this protection?

 

[pvgirl]

Doesn't the IMO DC switch satisfies this requirement?

For solar panels installed on buildings NEC 2017 requires module level rapid shutdown, requiring a rapid shutdown module at each panel, along with a transmitter to control those modules.

Does the SPD cover this requirement? Voltage Surge Arrester Device, 2P Surge Protective Device DC Photovoltaic Lightning Protector Low-Voltage Arrester 3.0KV (2P40KA)

Arc Fault protection is not surge protection. This is provided by the charge controller/inverter, sometimes requiring an add-on.

What would entail this? And would the Victron MPPT offer this protection?

This can be accomplished with a special breaker(midnite solar sells them), or built in to a charge controller/inverter. I don't believe Victron offers any of these protections in their charge controllers, which often means they are not suitable for solar installations in the US.

Also you should verify all components in your system are listed, in particular the breaker box, breakers, and spd before the charge controller.