Size of grounding panel to main

[Larry Akers]

It use to say if subject to a lighting strike minimum size ground should be a #8. Article 690.47 (C)(3) states minimum size the larger of 250.122 or 250.166. in article 250.166 (A) AND (B) states minimum #8. 250.122 shows that 15 amp could use as small as a # 14 wire. So what size would be the minimum size of the ground wire from the PV panel to earth. Would it be #8 from earth to the inverter or all the way to the panel. Or from the panel to the inverter be considered a equipment ground. Thanks for any clarification.

 

[augie47]

IMO, it depends on what "grounding" you are accomplishing.
Equipment grounding conductuors would be sized per 250.122 (690.45 in '08 NEC), Grounding Electrode conductors would be sized per 250.66 (690.47 in '08 NEC)

 

[Larry Akers]

What would call the wire attached to the PV panel down thru the inverter to the main?

 

[augie47]

PV is a weak area for me, so take it with a grain of salt. To me those would be photovoltaic output circuits and the equipment ground would be sized per 690.45 ('08 Code).
You really need to check that section for sizing the equipment ground as there are some variables.
(I have found it's normally sized per 250.122)

 

[GoldDigger]

PV is a weak area for me, so take it with a grain of salt. To me those would be photovoltaic output circuits and the equipment ground would be sized per 690.45 ('08 Code).
You really need to check that section for sizing the equipment ground as there are some variables.
(I have found it's normally sized per 250.122)

Have some salt:
The term photovoltaic output circuits refers to DC circuits which may be the output from combiner boxes, etc. The AC circuits are called inverter output circuits instead.
So for sizing, any equipment ground connected back to the DC side would be sized as you note, but any AC EGC will be sized under other rules. And it is allowed, for the most part, to combine the two EGCs on the run from the AC side of the inverter to breaker panels, etc.