GerryAZ
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Re: Level 1 charging with an ungrounded plug

Wed Jun 17, 2020 9:09 pm

billduck wrote:
Wed Jun 17, 2020 6:58 am
This is good information. Let me deconstruct it. Everyone understands that a 240 volt service is 2 each of a 120 volt sine wave that are phased 180 degrees apart. Are you saying that the voltage from a 120 volt recepticle on the pure sine wave inverter is kinda the same. That is, it is 2 sine waves at 60 volts separated by 180 degrees, time wise?
The inverter I am using is from reliable inverters - a pure sine wave inverter. Do not want to let the smoke out.
The inverter output is 120 volts RMS sine wave but it is either completely floating with respect to ground (which means bonding the neutral to ground would create a grounded neutral system and allow charging) or it is two 60-volt sine waves as you describe which yields 120 volts with both neutral and line conductors offset from ground by 60 volts. I suggest you ask the manufacturer of the inverter to find out if its output is floating with respect to ground. If it is floating (like both of my inverter-type generators), then you can create grounding plugs as I described earlier to ground the neutral and allow car charging. If the inverter output is not floating, you could get an isolation transformer to create a separately-derived system and ground the neutral on the output side of the transformer.
Gerry
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Oilpan4
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Re: Level 1 charging with an ungrounded plug

Thu Jun 18, 2020 1:56 am

Virtually all 120v inverters run 60v on the neutral and the hot, put them together for 120v.
A few years ago I was able to find exactly 1 inverter that ran a 120v hot and had a neutral bonded to ground.

Most but not all pure sine wave inverters fry when you ground one of the current carriers.
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GerryAZ
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Re: Level 1 charging with an ungrounded plug

Thu Jun 18, 2020 2:38 am

Oilpan4 wrote:
Thu Jun 18, 2020 1:56 am
Virtually all 120v inverters run 60v on the neutral and the hot, put them together for 120v.
A few years ago I was able to find exactly 1 inverter that ran a 120v hot and had a neutral bonded to ground.

Most but not all pure sine wave inverters fry when you ground one of the current carriers.
Good to know--I am starting to search for a 2 kW sine wave inverter (12-volt input) that I can use with test equipment which checks for safety ground by injecting a small current to ground. Like an EVSE, that equipment will not function if neutral is not grounded. I may need to use an isolation transformer if I cannot find one with neutral bonded to ground.
Gerry
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Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019

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Nubo
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Re: Level 1 charging with an ungrounded plug

Thu Jun 18, 2020 7:49 am

Since nobody's mentioned it, why not install a grounding rod in Earth and run a line from it to the ground lug of the receptacle to provide a reliable ground that doesn't require any tricks?
I noticed you're still working with polymers.

LeftieBiker
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Re: Level 1 charging with an ungrounded plug

Thu Jun 18, 2020 1:03 pm

Nubo wrote:
Thu Jun 18, 2020 7:49 am
Since nobody's mentioned it, why not install a grounding rod in Earth and run a line from it to the ground lug of the receptacle to provide a reliable ground that doesn't require any tricks?
That was why I suggested using the box as a ground source. You really aren't supposed to have multiple grounds for your house, as I understand it, but maybe a system like this is the exception...
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goldbrick
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Re: Level 1 charging with an ungrounded plug

Thu Jun 18, 2020 2:01 pm

I don't want to be pedantic but both wires - 'hot' and 'neutral' - are conductors and carry the exact same amount of current. If they don't, that's the definition of a ground fault and it will trip a GFCI and/or cause more serious problems. The 'ground' wire should never carry current in normal operation. It might carry a small amount for the GFCI test but the ground wire should never be used as a conductor in normal operation.

Oilpan4
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Re: Level 1 charging with an ungrounded plug

Thu Jun 18, 2020 2:03 pm

Or just run a 240v inverter.

Back when I got rid of my modified sine wave inverters I read the manuals and at least one of the samlex and xantrex manuals said not to attempt to make a bonded neutral and ground. Actually both have a GFIC receptacle so unless you take the inverter apart and attempt to modify it you can't make a N-G bond.
trumpvirus
Is going to get you.

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