[RE-wrenches] PV GEC

[Wallace W. Weeks]

Wrenches,

On a recent install I've come across a question I would like to get your thoughts on. 

In regards to running a GEC on a "separately derived power system",  more specifically A single phase 600 v residential PV system with a string inverter.

From my past experience and building from approved plansets throughout the bay area and Monterey Counties. I have always pulled a #10 ground with my DC conductors.

A recent conversation sparked The idea a local jurisdiction wanted a GEC (minimum # 8 AWG In conduit & #6 bare free air) pulled from the roof to the inverter ? Also #6 bare bonding the rails ?

Furthermore The GEC coming from the array shall not be permitted in FMC? The scenario was transitioning from EMT to FMC in an attic.

Referencing and potentially misinterpreting 
250.64 B,  It does seem to exclude FMC from approved means of protection ?

My questions are as follows.

-Is it a common requirement to bond rails with # six bare & run a GEC from the roof to the inverter ?

-Why would the transition from EMT to FMC not be acceptable because the GEC is in the raceway ? when In a scenario that is free from damage. For example in attic ?

Thank you for your clarification on these topics.

Cheers-W.W.W














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