I am installing a 2000w 120v power inverter in to new construction with no "grid power". My question is: Is it better to split the Hot wire in the main panel box for L1-L2 or better to install a sub panel and do the split there. I am the owner/builder and not an electrician as I'm sure you can tell. I am using a 125 amp main panel with 4-15amp, 2-20amp and 1-30amp circuits. Thanks in advance

Is this a temporary hookup until "grid" power is hooked up? Not sure what it is you want to achieve.

I built this house to use wind/solar/generator power only. Grid power is not possible. I wired the house as if it were a normal residential building. I hate to use the term "green" but that's basically it. The way I have it wired now is I split the HOT inside the main panel with a 40 amp breaker to get the same amount of power to both sides of the panel. I also have a service disconnect outside with a manual transfer switch for the times I need to run my generator for 240v. My concern is with the way I have the HOT spit. Should it be inside the main panel or another way?

With a 2000 W inverter, you only have 16A available at 120 V.
30 A at 120 V isn't going to happen.

Would have considered a 240 V inverter, in esscence a system designed to supply 120/240 VAC.

You might have been better off using a 240 V panel wired to the generator for the 240 loads.

Then you could have used a generator transfer panel to select which loads are used.

Asymetricly, things could still work out. A genuine transfer switch or interlock kit. See Generator InterLock Kit for the generator. This will absolutely prevent both from being engaged at the same time.

And use a generator transfer panel from a single breaker. These panels basically can be connected to a single load in the panel and each selected.

In generator mode, the generator would not be loaded anywhere near evenly.

I doubt you would want a 240 panel and a 120 V panel without the ability of the generator to supply the 120 V loads.

Check out Schneider Electric | Xantrex

I have researched a lot of the options before deciding on the AIMS 2000 watt inverter. The 30 amp was more of a "what if" I really can't see a need for it anytime soon. As far as the transfer switch, I am using a switch that if one breaker is turned on the other also moves to the off position. I do appreciate the information. But, it does not answer my original question. Maybe it’s just something that needs not be worried about.

My confusion is "split the hot" and "When I need 240". This seems to be an incompatible option. When you "split" the hot, which I interpret to mean connect both busses of the 120 together, the panel is incapapable of delivering 240.

Thus it seems you need separate panels for 240 and 120 V. The 240 panel could provide 120 V loads though.

On your manual transfer switch, hook up the generator as usual.With the inverter,split the 120 power wire on the line side of the transfer switch.

Matt, thanks for the reply. I was leaning in that direction but just wasn't sure.
Thanks everyone for the help.