[RE-wrenches] grounding the Enphase inverter

[Bill Brooks]

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-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at 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-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at 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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