Parallel Neutral

[ceb58]

Looking at an install done on an inverter brought this question to mind. Here is the set up. Supply side taps from main panel to fused disconnect for inverter 2 hot 1 neutral. In the disconnect neutral has bonding screw installed and a new ground rod installed and grounding electrode conductor bonded to neutral bar and bonded back to the original GEC . From there it is 4 wire to inverter 2 hot 1 neut. 1 EGC. My thought is because the neutral in the main panel is already bonded to the original grounding electrode and now you have tapped that neutral there is no need for the GEC to rebond at the disconnect. The only bonding jumper should be from the original rod to the new second G rod. I am thinking this bond from the disconnect could become a parallel neutral or is it over thinking the thing?

 

[LarryFine]

I tend to agree, if the disconnect is not considered service equipment.

 

[ceb58]

I tend to agree, if the disconnect is not considered service equipment.

That questions is is it service equipment. The feed for the disconnect is in-between the meter and main panel so the wire is unprotected and it serves as the overcurrent protection and disconnect for the inverter.

 

[jaggedben]

The way it is done is perfectly legit for an additional service disconnect as allowed in 230.86.

You can run around in circles for a long time trying to figure out if a PV supply side connection like this is a service disconnect or not. My opinion has always been that it should be treated as such since the fault current issues are the same. Or, you can go overboard to avoid the parallel ground-neutral path, even though the code thinks it's no problem if both disconnects serve loads. Every attempt to get real clarity on this in the code has been so far shot down.