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bldginsp
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# Posted: 8 Dec 2015 08:58am
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I think the takeaway is that you need to know if you are dealing with an inverter with a 60/60 split, or not. Thus far they have only been described as 'portable'- is there another more technical description? As Don said- you should only use the inverter for what it is intended for, which is that you plug appliances directly into the inverter, and not use the inverter to power up a true single phase 120 hot/120 hot/neutral configuration.
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bldginsp
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# Posted: 8 Dec 2015 09:04am - Edited by: bldginsp
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Quoting: Don_P If I ohm the receptacle on an inverter and it is not bonded, I cannot get continuity between either slot and ground.
That would be true in either case.Quoting: Don_P Then a panel cannot have a bond between neutral and ground, Nor can anything downstream of that inverter.
Correct, for a 60/60 split inverter. But these, apparently, should never be used to power a panel to begin with.
You should get 60 volts to ground with one of these inverters. Hmm- on second thought- since there is no grounded neutral, I don't really know. Like a larger transformer system with no neutral, there is no voltage to earth, only to the other phases. these 60/60 inverters are basically like a transformer with no neutral that is used only across phases, getting 120v. There is no way to get 60v out of it, which is good, cause that would fry your appliance.
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MtnDon
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# Posted: 8 Dec 2015 05:10pm
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Quoting: Don_P Can I read if it's the half volt system by checking either slot to ground for 60 volts...or will I simply realize that it was a half voltage setup?
I don't know for sure. My mod sine wave inverter left for Los Alamos so I can not go and probe it. I believe the chassis of these are often supposed to be grounded to the vehicle chassis; I don't know how that affects things. ??? (need the scratch my head smiley)
There are two UL standards in play here. UL1741, aimed at use in a RE situation (renewable energy off grid) and UL458, aimed at mobile markets, RV and Marine.
Here's something further I found....
" UL1741-listed inverters must allow for the neutral-to-ground bond to only occur at the main AC service panel. UL458-listed inverters have internal neutral-to-ground switching relays to allow for this bond to occur at the inverter if in off-grid mode, OR at the utility power service if it is connected to a utility hookup. Some inverters are listed under both standards, so you'll need to read the installation instructions carefully. Many Internet sources market off-grid inverters as "UL-listed," but don't clarify the actual listing, so they may not be appropriate for residential use."
source
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Don_P
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# Posted: 8 Dec 2015 08:09pm - Edited by: Don_P
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Quoting: Bzzzzzt I checked mine with a meter and there is NOT a bond between them on the inverter. Seems like there should be, but nope.
Quoting: bldginsp Quoting: Don_P If I ohm the receptacle on an inverter and it is not bonded, I cannot get continuity between either slot and ground. That would be true in either case.
How are you metering for a bond in the inverter?
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bldginsp
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# Posted: 8 Dec 2015 10:49pm
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I'm not. I said that just based on the idea that if the neutral is not bonded to the ground, it's not possible to get a voltage from a hot wire to a ground, there is no path. That's true of standard 120/240 setup, but also true of the 60/60 setup, I guess, because it has no neutral to begin with. The only way to complete a circuit is across the two 60v hots. At least, that's what I'm guessing based on what we know about them.
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Bzzzzzt
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# Posted: 9 Dec 2015 12:06am
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Quoting: Don_P How are you metering for a bond in the inverter?
What I was referring to was using a standard ohm meter or continuity tester to see if there was continuity between the neutral slot and the ground slot in the receptacle of my inverter. I discovered accidentally that it was a 60/60 inverter when I was trying to wire up a ceiling fan. Had never thought about that as a possibility before then. It just goes to show you that even someone who is a certified expert in a field can learn something new every now and again.
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Don_P
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# Posted: 9 Dec 2015 07:18am
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Thanks Bzzzt.
We have a freshly minted master sparky on the job today, more breaktime fodder 
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Bzzzzzt
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# Posted: 9 Dec 2015 08:30pm
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Usually the newbies are very interested in how stuff works. I've been doing it long enough that I don't really care HOW it works, only that it DOES work.
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