NEC 690-35

[Nalagia]

Hi,

I am looking for some feedback for NEC 690-35 which basically states that the PV system is permitted to opertate ungrounded if the following items are met. I think it's pretty clear that "ungrounded" to the article means ungrounded on both the "source and output side". I have a system that is grounded on the DC side to the negative leed thus the items listed in the article do not need to be met. Correct ?

 

[cameljoc]

PV Systems

PV Systems

I just came off a very large Solar Plant in central California. One has to understand 690 and why its used. The Terms Input and Output has to deal mostly with your DC Voltage applcation as it applies to the combiner box and inverter. The grounded negative applies only to the DC Side of the PV System for fault protection. It has nothing to do with the AC (collection system) side of the system. NEC now looks at it as a power supply and distribution system. The Local Code Enforcement Inspector will be glad to assist.

 

[jaggedben]

I have a system that is grounded on the DC side to the negative leed thus the items listed in the article do not need to be met. Correct ?

That is correct.

I think it's pretty clear that "ungrounded" to the article means ungrounded on both the "source and output side".

System grounding of PV systems refers to the DC side only. That pertains to 690.35 and other system grounding wording in 690. The AC side may or may not have a grounded conductor. That is not addressed in 690. And just to be clear, none of this is the same as equipment grounding, which is always required on both the AC and DC side.

Your use of the terms "source and output" is imprecise, as output could refer to both PV output circuits (DC) or inverter output circuits (AC).