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2 questions

Tyler702

Desert dweller, quiet prepper
Joined
Aug 20, 2020
Messages
178
So I basically have Wills identical 24V 2000W setup. Mounted on a wood panel on the wall of my garage. The grounding screw on both the inverter and the CC are not currently being used. Am I ok to run a 12 or 10 guage wire individually from both, directly to my neg distribution block? At this time, nothing is earth grounded, except the ground mounted pv panel out in the backyard, which is wired from the pv frame to the steel frame its attached to, which is sitting directly on the ground.
And #2, I wish to tap one of the outlets on the inverter to bring power around one side of the garage to the other, to my work bench, and affix a receptacle there. Would it be wise to make that a GFI receptacle? Any harm one way or another?
Thanks in advance.
Tyler
Btw, the inverter is the Giandel 2000W pure sinewave unit.
 
In a garage, you should ground the bodies of the inverter and charge controller to earth.
ALL ac power should be fed ONLY through GFCI protected wiring.
Concrete is a earthed conductor, and you can EASILY be electrocuted from ground impedance...
 
Ok. So since the panel w all the devices is mounted on an exterior wall in the garage, I could drive a stake into the ground just outside the foundation, and penetrate thru the stucco with a heavy gauge wire, and a tie that to my negative distribution block, then run my inverter & CC ground leads to that? As depicted in the attached pic in orange?20201127_211447.jpg
 
I think this stuff you're talking about grounding includes the negative side 24V DC. Probably no need.

Chassis of everything that includes 120V AC (probably just the inverter) should be grounded.
Maybe also chassis of charge controller as Supervstech says. If the PV strings exceed 50V I think that could be a good idea. If < 50V I wouldn't worry.

I would connect ground to ground of the utility wiring, if present in the garage. Otherwise to a ground rod. Code likes to have foundation steel connected too, but I don't know how well foundation bolts are tied in - I think they're usually just a "J" bolt hanging under re-bar.

Only inconvenience of GFCI is if it trips when you don't want it to. Some of my appliances are a bit leaky.
I'm not aware of a need or requirement to have GFCI for use inside a garage. Just for kitchen/bath/outside. But I see Supervstech's point that concrete floor isn't well insulated like wood/carpet/vinyl, so I guess that makes sense.

By the way, do we know if the Giandel has a true neutral which can be grounded? Or if it produces +/-60V with two hots?
 
Unknown on that one Hedges. The only thing that even mentions grounding in the Giandel manual is this. So I'm still a bit confused. I currently have a 4 post neg distribution block that all neg dc wires (inverter/CC/BMS C- from battery negative) share in common. So I guess, if I understand the manual right, I may need to pound a rod into the ground just outside the panel wall, and bring a wire inside to the neg distribution block, then also ground the chassis Giandel and chassis CC to that same distribution block as well? This would effectively earth ground everything needed as indicated by Supervstech. Am I ok with this course of action? From there, bringing power around to my workbench from the inverter, do I still need a GFI receptacle? It's certainly NOT in a wet or harsh place. Just inside the garage, for general purpose use like charging my cordless drills, laptop and general shop lighting.
20201127_225741.jpg
20201127_223120.jpg
 
I think this stuff you're talking about grounding includes the negative side 24V DC. Probably no need.

Chassis of everything that includes 120V AC (probably just the inverter) should be grounded.
Maybe also chassis of charge controller as Supervstech says. If the PV strings exceed 50V I think that could be a good idea. If < 50V I wouldn't worry.

I would connect ground to ground of the utility wiring, if present in the garage. Otherwise to a ground rod. Code likes to have foundation steel connected too, but I don't know how well foundation bolts are tied in - I think they're usually just a "J" bolt hanging under re-bar.

Only inconvenience of GFCI is if it trips when you don't want it to. Some of my appliances are a bit leaky.
I'm not aware of a need or requirement to have GFCI for use inside a garage. Just for kitchen/bath/outside. But I see Supervstech's point that concrete floor isn't well insulated like wood/carpet/vinyl, so I guess that makes sense.

By the way, do we know if the Giandel has a true neutral which can be grounded? Or if it produces +/-60V with two hots?
NEC code has required all receptacles be GFCI protected in a garage for a long time now...


Yes, all garage outlets must be GFCI-protected-no exceptions. Since 2008, GFCI outlets have been required for “all 125-volt, single-phase, 15 and 20-amp outlets” in the garage. In fact, both the NEC (National Electric Code) and the IRC (International Residential Code) require this.Mar 20, 2018
1606572837855.png
georgebrazilplumbingelectrical.com › ...

 
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OK, I've never owned a new house. Or a new car.

I think OP's inverter only has sockets for plugs. Could use:


A portable GFCI like that would disconnect both line and neutral. An outlet or breaker GFCI would just disconnect line.


Line and neutral of house wiring are supposed to be electrically connected, at one point. Usually this is the main breaker panel, where grid power enters. For marine/RV with shore power plug, it is connected through shore power pedestal to that main panel. When unplugged from shore power, neutral is connected by relay to ground inside the inverter.

For a stand-alone inverter such as this one, with no AC input, it is often floating. Some inverters can tolerate having neutral wired to ground externally. Some can't, because they deliver 60/120V split-phase, with the center tap connected to the battery. Having 60Vrms relative to ground (85Vpeak) is less hazard than 120Vrms, 170Vpeak, but could still cause a harmful shock. A GFCI may note that it is wired incorrectly. Some will still function, but the "test" button may not (because test current leaking to ground through a resistor would be half as much.)

I suggest using a volt meter to measure AC outlet voltages (Line to neutral), (Line to ground), (neutral to ground), (line to battery negative). Tests with high impedance (a meter) aren't completely conclusive. Try also an incandescent bulb (to apply a load) across those pins, and measure voltage across the bulb. With inverter shut off, measure resistance between neutral and ground.

Maybe neutral to ground is already zero ohms, in which case nothing to do.
Maybe neutral to ground lights a bulb or applies voltage across it, in which case it can't be grounded.
Maybe line to battery lights a bulb or applies voltage across it, in which case grounding neutral could make battery wires electrically hot with AC.

Ideally you end up with neutral grounded, either inside the inverter or externally. Then it is like house wiring and GFCI work and self-test as intended. If you can't then you just have portable inverter generating 120V across its line/neutral; portable GFCI would be good to try. Grounding the ground pin is still good, so if you hold a tool or appliance its case is grounded and won't shock you.
 
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