The better question is why is there a solid ground in the inverter.
As I stated before-we are talking about system grounding-with 100+ years of electrical history and precedent to back it up. System grounding rules are not open to a lot of discussion. That is why my recommendation since before they released their first product was to go ungrounded. Just because it is a pain, and we think there is no technical reason, does not mean we can ignore the rules. As I said in my post, this is not really a safety issue, but it is very much a compliance issue. System grounding is so much a part of our electrical culture, that tiny electrical supplies like PV microinverters were never really considered. Any installer can use the "don't ask, don't tell" method of installation, but once we start down that path, the ability of the human mind to justify actions is limitless. We have to go back to why we ground systems in the first place. It is to prevent the voltage on the system conductors from wondering too far from ground potential. There are other ways to prevent this, but in the U.S. we mostly use conductors (not a variety of conductive materials without clear ratings). The advent of the WEEB, with all its great benefits, does not fundamentally change system grounding. The sooner we get PV systems ungrounded, or resistively grounded, the better the whole U.S. PV industry will be. To that end, everyone should move to PV Cable/Wire and modules with PV Cable/Wire so we are using better products than USE-2 and we can easily transition to ungrounded inverters as they become more available. We already have several so now is not a bad time to start thinking about it. Bill. From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller Sent: Friday, March 04, 2011 9:58 AM To: RE-wrenches Subject: Re: [RE-wrenches] grounding the Enphase inverter Bill: Other than complying just because this is a rule that has to be followed, is there any logical foundation to the requirement to provide a #8 ground to a circuit with OC protection at 20 amps? If there is a valid safety reason, then let's all get behind it and become adept at providing this GEC. If the rule makes no sense, let's advocate that it be changed. What is the reason for providing this GEC to an inverter? Thanks in advance. William Miller At 09:51 AM 3/4/2011, you wrote: System grounding requirements. -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Mark Frye Sent: Friday, March 04, 2011 7:51 AM To: 'RE-wrenches' Subject: Re: [RE-wrenches] grounding the Enphase inverter The interesting thing to me is the underlying assumption in the Code that a GEC is requried for grid-tied inverters at all. Why isn't EG sufficient for function and safety. Which of the following common electrical equipment has the same requirement: UPS Motors with regenerative energy disipators DC power supplies Standby generators ?? Mark Frye
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