Little help with my system please

Re: Little help with my system please

To answer the GT inverter question:

1000 watts / 110 Volts = 9.1 amps nominal maximum

9.1 amps * 1.25 NEC breaker/wiring derating = 11.4 amps minimum

So, the branch circuit for this inverter should be 15 or 20 amps (typically 14 awg or 12 awg wire minimum, respectively).

A 200 amp main panel with a 200 amp main breaker is "legal" to support 20% of its rating as solar GT power input--Or 40 amps @ 240 VAC maximum--A 40 amp double pole breaker would be the maximum allowed to be wired to your sub-panel. The 40 amp breaker should be installed at the "bottom" of the main panel (opposite end of the AC bus bars from the 200 amp input breaker).

The sub panel you are wiring in is usually only allowed to be used for connecting GT inverters into. Your system would be allowed 4x 20 amps single pole breakers.

You will also be following electric code regarding the wiring/installation of the solar array? If you have lightning in your area, you don't want a strike hitting the panels and bringing the energy into your home (bedroom/office/etc.). Most installations require metal conduit from the roof to the first disconnect/protective breaker panel before you can go to Romex (or similar) interior style cabling.

As Marc said, in most locations, installing this system without permits/utility approval/licensed electrician is illegal. And can be very dangerous. Pretty much all of the small GT plug and play inverters sold in the US are not UL/NRTL Listed and illegal to connect. They also tend to have a nasty habit of overheating and early failures (not very reliable).

Also, you need to find out what kind of power meter you have for your home. The range from:

Old mechanical meter, will turn backwards when you generate excess power (more or less, Net Metering without utility knowing).
Mechanical meter with one way clutch... Any excess power does not turn meter backwards (you give extra power to utility for free).
Digital meter that turns forwards/backwards (net meter).
Digital meter that turns forwards only (the utility charges you for putting excess power on grid).
Digital meter that reports unusual power conditions to utility (excess power generated, unusual power details).

If your utility bill drops, the utility may send somebody out to figure out if you are illegally connecting a GT solar power system (look for panels on roof, look for meter turning backwards during day).

If you generate more power than you use (I did this with my GT system install--Turned on after approval, but utility took ~1 month to install new meter/change billing plan)--Utility computer may guess that meter reader read the meter wrong, and "play" with the numbers until they "make sense". In my case, I went from what should have been a $40 summer credit to a ~$187 bill after the computer "gamed" the meter numbers.

Grid Tied Inverters do work well and there is not really much reason to experiment on a Utility connected home. You might be able to bury a 250 watt installation and not have the utility notice. You might even be able to bury a 1,000 watt installation if you use a fair amount of power (HVAC, electric stove/hot water/etc.).

But with full professional/permitted installs getting down to the $3-$5 per Watt (~$3-$5,000 for your system capacity--But probably realistically based on a 5-10kWatt system, small systems will have minimum charges/permitting/engineering fees that would probably make a small system more expensive to install). Plus (at least for the near future) a 30% federal tax credit.

You could be very surprised if you install your system at what happens down the road. You may very well be lucky and nothing happens. But there is a risk.

Lastly--Even off grid power systems still need to be properly designed. Battery banks and DC systems have a tremendous amount of stored energy and have other safety issues. Even they should be treated with respect when designing/installing.

-Bill