Gridtie, breaking grounded conductor [RE-wrenches]

[Bob Maynard, Energy Outfitters]

Wrenches,

Now that Oregon has a gridtie rebate program (severely under funded), we are starting to feel many of the inspector related issues that have been discussed before.  Oregon's program in addition to inspection by the AHJ, must pass inspection by the rebate program's own inspectors.  The contractors in certain Oregon jurisdictions are being told by the AHJ's inspector that a  dc disconnect is required at the array on roof mounted arrays, any advice is appreciated on the best way to address this.

More importantly is a recent issue brought up by a program inspector.  What could be happening?

The inspector said that he received an electrical shock from the negative conductor within the dc disconnect of a standard residential, battery less, PV system. At first, this seemed very odd to me since the unbroken conductor should be bonded to ground and thus possesses the same potential as ground. Upon further discussion with him,  he is convinced the system is ungrounded since the grounding bond occurs on the ac side and the GFI prevents the proper dc grounding. He contends that the bond needs to occur at the source; the PV array. I am still puzzled about this. Since the grounded bond occurs within the inverter, does this not properly perform the bond required between the negative dc conductor and ground. Could there possibly be a capacitive charge build up. If so, how is it possible with a bonded connection to ground?  His recommendation now is that the dc disconnect must break the array positive AND negative.

We've got some real pro's on this list and I look forward to their input.

Regards,
Bob Maynard
Energy Outfitters

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