backfeeding energy into my home

[Bigbillsd]

Curious. Has anyone used a panel, like a 100w panel and a micro inverter to plug into their homes power outlets? Based on how the microinverter works if the grid went down it would instantly stop producing power so there wouldn't be a chance to hurt anyone thinking the power was out, but it really wasn't.

Just curious. I have a friend in rural alaska that told me there aren't even building inspectors where he lives and you can build anything you want. There are no permits to get.

-Bill

 

[Will Prowse]

They are not code compliant, so not recommended. Anything connected to grid needs UL listing and code compliance. If you are off grid, you can use anything you want.

 

[Taz1004]

If we get the UL certified inverter, can we just hook it up or is there any further step required to make it legal?
I don't mind going with off-grid but being able to connect to any outlet with grid-tie seem more attractive. And it's simplicity of setup. Don't care about it going back into the grid. Is there way to achieve that with off-grid? Legally?

 

[Taz1004]

Ok, after watching this video

I decided not to go with grid-tie.
Off-grid requires no permit? Would the guy from power company come out and see my off grid solar panels and make an issue out of it?

 

[Supervstech]

I think ANYTHING tied into a home needs a permit and inspection if the county you live in has inspections... many don’t.
I suppose, if YOU own the home, and you don’t have it insured, no permits are required. If insurance is on it, and something is installed without permits, they can rightfully deny any damages claim... even if it is natural disaster damage.

 

[Taz1004]

Thanks for the reply. But technically, nothing would be "tied" into the home with Off-grid wouldn't it? I'm not even planning to mount the panels on the roof as I have no south facing roof surface. Just ground mount them in my back yard. I'm just wondering if any authority see the panel and assume it's grid-tie. How would they check?

 

[Supervstech]

Thanks for the reply. But technically, nothing would be "tied" into the home with Off-grid wouldn't it? I'm not even planning to mount the panels on the roof as I have no south facing roof surface. Just ground mount them in my back yard. I'm just wondering if any authority see the panel and assume it's grid-tie. How would they check?

Oh, I installed off grid stuff in my own home, tied into the main panel and everything. I’m not saying it can’t be done, just that if no inspections or permits are pulled, insurance inspectors can deny anything.

 

[Bigbillsd]

I talked with a tech from legionsolar and there stuff is not UL listed. But it really's seems like it would work. And if there was an issue, you could just unplug the panels from the 120v outlet and put the equipment in the trunk of your car and drive away. Its an incredibly elegant solution.

I may just buy the initial 300w complete setup for the $599 list price to test it for grins and giggles. My only problem is the distance from my circuit panel to where the panels/inverters reside. The controller only talks to the inverters via a private WiFi connection which might not work due to the distance and all the walls involved. The tech suggested extending the Controller WiFi antenna's closer to where my panels would with coax cabling.

But in hindsight, it might just be simpler to extend the wires from the clamp on cores measuring the power consumption from the grid to the controller.

 

[offgriddle]

The two voltage sources would be out of phase unless the microinvertor matched phase with the grid. Even if the microinvertor is designed to not pass panel voltage when the grid is down, sht happens. When it comes to risking accidentally backfeeding the power companies transformer that serves you, it is best to not do it because you cannot 100% rely upon the human element to act as a transfer switch flawlessly by shutting off the main breaker every time you wish to backfeed an outlet, which is what must be done for safety.

 

[Bigbillsd]

The two voltage sources would be out of phase unless the micro-inverter matched phase with the grid. When it comes to back-feeding the power companies transformer that serves you, it is best to not do it because you cannot 100% rely upon the human element to act as a transfer switch flawlessly by shutting off the main breaker every time you wish to back-feed an outlet, which is what must be done for safety.

Wouldn't all micro inverters have to match the phase to ever work for grid tie installs? Not everyone can afford to buy enough solar capacity to never use some of the power from the grid during the day. Like when you turn on the Air Conditioner or electric stove/oven.

The way they designed this system there is no need to shut off any breakers to use it. The grid tie micro inverters they use don't produce power if you shut off the breakers to the grid. Is't it a requirement to stop producting power if they are grid tie models and the grid is unavailable? -Bill

 

[Rider]

Wouldn't all micro inverters have to match the phase to ever work for grid tie installs? Not everyone can afford to buy enough solar capacity to never use some of the power from the grid during the day. Like when you turn on the Air Conditioner or electric stove/oven.

The way they designed this system there is no need to shut off any breakers to use it. The grid tie micro inverters they use don't produce power if you shut off the breakers to the grid. Is't it a requirement to stop producting power if they are grid tie models and the grid is unavailable? -Bill

In theory, yes. But what @offgriddle is saying is that components can fail. There is no safety in that event and power could go back out onto the grid if the main breaker is not turned off.

There are only two ways to do this properly, either use a transfer switch, or a safety interlock on the main breaker. I use an interlock when using my generator, it prevents the main breaker from being turned on when the genny breaker is on. Both cannot be on at the same time, physically.

 

[Bigbillsd]

Understood, I have an interlock for my generator. But turning off their main breaker with a grid tie system seems pretty odd to me. If I were off grid I would be using batteries and probably not micro inverters.

 

[Will Prowse]

Well, if you just want to run your house panel off an off grid inverter, easiest way would be to wire up a ATS, disconnect the main breaker from grid power, and turn on the inverter when its connected to ATS. So pretty much, make a generator back up system (or pay an electrician to do it to code if you are lazy), then instead of using a generator, use a split phase off grid inverter, and you are set. If you have a roof mounted array and grid tie inverter, bypass it to charge/discharge batteries instead. Lots of options.

 

[Rider]

Lots of options.

Yes. I was looking at it strictly from a 'plug it into an outlet and backfeed' scenario, didn't assume anything else.

 

[Bigbillsd]

I'll bite, whats an ATS? Some sort of sinewave generator?

 

[morth]

Automatic transfer switch

 

[Bigbillsd]

Are there micro inverters available that will continue to put out 120v when there isn't the grid sinewave available after disconnecting the Grid?

 

[Supervstech]

Are there micro inverters available that will continue to put out 120v when there isn't the grid sinewave available after disconnecting the Grid?

You would have to have a transfer switch to isolate the grid if there was... or the load would outpace your equipment.

 

[robstrom]

I'm new, and perhaps not so bright. I'm missing the point of doing this. These microinverters are by nature, not running a house. Why not use them where you need them?

 

[Supervstech]

I'm new, and perhaps not so bright. I'm missing the point of doing this. These microinverters are by nature, not running a house. Why not use them where you need them?

They are micro... they dont put out much wattage.
Most are sub 300watts... usually they are tied to each panel, then combined to send wattage out.