Grounding over kill

Question is ground wiring going a bit overboard ?

example: The enphase cabling has it's own ground lead which connects the inverter frame to ground. The inverter frame has an additional ground connection.
The inverter frame is mounted to the racking mounting system which is also supposed to be grounded using a separate ground wire.

Do we really need 2 sets ground wires all going to the same connections when the enphase cable will ground the inverter the frame and the mounting rails ?

Comments

Toddbaily,

Great observation: The answer is "It depends". You are completely correct that the running of a #8 grounding conductor parallel to the engage cable is duplicating the ground path and may be avoided in some cases.

Even though metal is touching metal in the inverter frame and racking, it isn't a reliable (or NEC approved) path to ground or Grounding Electrode Conductor (GEC). You need to add WEEBs to the system for it to qualify. Here's a paper by Enphase on the topic:

This can save you money and the appearance of an unsightly bare copper wire, but there are at least two reasons why you might want to use a #8 bare Cu wire.

Your AHJ is stubborn and insists on the bare #8 wire and your time is too valuable to argue with her (or him).
You have even the slightest concern about a lightning induced surge in the system and you don't want to route that potential into your sweet little inverters and then through a puny #12 stranded wire and all its resistance laden connectors.

Here's a detail from an Enphase document showing the two grounding conductors:

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