Transformer location

If I set up a small grid tie inverter on one leg and it produces more power than is consumed by that one leg, will it flow back through the meter, then to the other leg? Or will it hit the other leg before hitting the meter?

Yes. Do 120v grid tied inverters exist? Anyway, as phrased, the answer is yes, to the first question.

All exporting configurations, including zero export, will cause some single leg export. It's unavoidable unless you isolate and balance your loads.

For what it is worth those 120vAC plug in micro grid tie inverters are a waste of money in my experience. Not only do you have to carefully follow sequence in how you turn them on, so they do not give up the ghost, they will just fail anyway after a short time. There is also the fact that without a grid tie agreement with your electrical company that it will quickly bring a representative out to tell you to cease and desist using it now that smart meters are common.

I played around with one back 5- 6 years ago when I first decide to investigate PV utility for accomplishing anything. I was scrupulous to ensure that i always had an adequate load so that no back feed would occur. I also was very careful in setup/start of the unit. After a couple of months of babysitting it it just up and quit working one day. Do not recall what it cost me but it did not prove itself as a good idea.

Just exactly is it you are trying to do with your PV setup? I have found that going with a GAB (grid as backup) Off grid AIO with LiFePO4 batteries does make for a worthwhile setup. Better bang for the buck.

Sometimes I just like to play with electricity. It was a $90 inverter so I figured why not. At idle my house consumes about 1500w of power, 600w of that being my home office. A while back I set up 4x240w panels on the back patio with an oukitel 2kwh battery for the deep freezer.

So I bought the thing and hooked it up just to see what would happen.

Unrelated, i have a 3k growatt set up as SUB mode powering my office, with no panels, since they're in my garage waiting for me to erect a new structure.

nasomi said:

Sometimes I just like to play with electricity. It was a $90 inverter so I figured why not. At idle my house consumes about 1500w of power, 600w of that being my home office. A while back I set up 4x240w panels on the back patio with an oukitel 2kwh battery for the deep freezer.

So I bought the thing and hooked it up just to see what would happen.

Unrelated, i have a 3k growatt set up as SUB mode powering my office, with no panels, since they're in my garage waiting for me to erect a new structure.

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Understood. An affliction that I suffer from as well.

hwy17 said:

Do 120v grid tied inverters exist?

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Yes, I have an Outback FX3648 (not currently connected) that is 120V only and could sell back to the grid.

If you have a 2400W 240V GT PV inverter, outputting 2400W, and your house loads are 1800W at 120V,
then yes, it will export 1200W (10A) on one leg and import 600W (5A) on the other leg.

Load draws 15A at 120V, gets 10A from inverter, 5A from grid, and returns 15A through neutral to grid.

The meter may combine current of L1 and L2 magnetically and be none the wiser. Or it could measure them separately.

If you happened to attach a transformer with 120/240V windings to the grid it could also import on one leg and export on the other, due to imbalance.

There are better ways to do this without messing with the utility. Put a relay, contactor or ATS of sorts between the appliances you want to power (e.g. office circuit, hot water tank, washing machine, microwave circuits) and the micro inverter. That way, you are doing it more safely and without upsetting the utility.

nasomi said:

will it flow back through the meter, then to the other leg?

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Yes

timselectric said:

Yes

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I figured that was the case. I wasn't sure if the transformer was after the meter or before.