[RE-wrenches] Replacing grounded inverters

[August Goers]

This topic came up on the list previously. Since isolated transformer based
inverters are going the way of the dodo, the only reasonable inverter
upgrade choice is to replace old inverters with new transformerless models.
As was previously pointed out here, these modern inverters have much more
robust ground fault and arc fault detection capabilities, so they’re safer
anyway. We just phase tape up the previously grounded white DC
conductor(s), make sure the positive and negatives on the DC side are
switched, and call it a day. I realize that some of the NEC technicalities
are being bent here, but this solution is the lesser of evils.



August





*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *Glenn Burt
*Sent:* Friday, July 22, 2016 5:08 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Replacing grounded inverters



If you read some of the proposed changes for the 2017 NEC, it is looking
life there will be no problem replacing isolated inverters with
non-isolated versions. In fact the proposed wording seems to allow either
USE, or PV wire to be used with non-isolated inverters explicitly going
forward.
It made me feel better about doing recent replacements.
I'm having more trouble with the TL inverters and AFCI issues on older
systems, however.
------------------------------

*From: *Gary at Santa Ynez Valley Solar <Gary at SYVSolar.com>
*Sent: *‎7/‎21/‎2016 21:43
*To: *re-wrenches at lists.re-wrenches.org
*Subject: *[RE-wrenches] Replacing grounded inverters

We are all facing having to replace the old transformer based inverters
when they run out. Really difficult to find replacements. Against code to
replace with transformer less ones. I wonder if a DC/DC transformer could
be installed just ahead of the transformer less inverter for isolation
purposes? Not clear on the concept.





Gary





Gary Gordon



   [image: cid:image001.jpg at 01D06621.23813A90]

   www.SYVSolar.com <http://www.syvsolar.com/>

   PO Box 688

   Santa Ynez, CA  93460

   805 688-1213

   NABCEP Certified Installer

   CA Licensed Solar Contractor
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