New construction - normally comes with 200 amps coming in. I asked for a additional 100 amp source.

Now what i see is a 300 amp coming in, 200 amp pannel and a sub pannel connected to the 200 pannel. Can this be right?

How do I know I have 300 am coming in?

I am not an electrician; repeat, NOT. However, free advice being worth what you pay for it, generally, here goes. If you have 300 amps coming in from the meter and a sufficient number of properly sized connections for drawing that much power, then you have 300 amp service. 200 amps being, if not a standard then at least commonplace enough to be familiar and reasonably priced, is is common to use a 200 amp breaker box for the main service and add an additional panel to provide the extra connections needed. If you would rather have one big box, then say so now and be prepared to pay a little extra, but I don't see any benefit to doing that, myself.

Anyone here who is an electrician or knows more about it than my jackleg self, please correct any mistakes or misstatements.

You have a 200 amp service with a 100 amp sub-panel that is tied into this service.
Very rare that you would have a 300 amp service, unless your home is real large.

ok this is where I dont know what is going on.

I paid over 2500 for this additional 100 amp source. If I have 200 coming in and a 100 sub pannel, is it worth the price I paid?

Could not comment on the price as this can vary from area to area as well as many other factors, length of wires to street service, type of panel, and a host of other factors.
If you paid for this additional service and you got both a 200 amp panel and a 100 amp panel, that is fed off of a wire feed that is connected directly to the meter located elsewhere then you got what you paid for. If however the 100 amp panel is fed from a ckt breaker located within the 200 amp panel you still have a 200 amp service with a 100 amp sub-panel connected.

In short, there is no real way of answering definitively without a physical inspection. The fact that you have 2 circuit breaker panels means nothing. It is all in how they are wired, the size wire used, etc. etc. Generally, homeowners really only care that they have sufficient connections of the proper size plus some room for future expansion, but after paying that much for extra capacity you deserve some peace of mind that you're getting what you paid for.

If you have reason to doubt your contractor or sub-contractor, then it would be best to hire an independent electrician who is qualified to inspect what you have. The number of panels really doesn't make any difference one way or the other, unless it matters to you, the homeowner and the one who is footing all the bills. I will say that while it is rare for licensed professionals to take advantage of someone who doesn't have their technical knowledge, it does sometimes happen. A good general contractor knows this and can be your best asset on the job site and best protection against being ripped off. Try not to get him/her too ticked off at you while at the same time getting the reassurances you need.

If you can see the main wires coming in from outside into your panel (sometimes it means taking off the panel face to see these), then that'll be your key. A normal 200 service has 3 big wires coming in 1 for neutral, 1 for 100 amp, another 1 for 100 amp. If you have a 4th wire coming in, there's your 3rd 100 amp service, making it a total of 300 amp.

What in the world would you need 300 amps for anyway?

Jay, I don't know if it's common enough yet to call it a trend but I've been seeing more 300 amp service run recently, and not just on McMansions. I can understand it I guess if you think about garages, shops, swimming pools, outdoor lights, room for future expansion, etc. etc. Not everyone is too concerned yet with power bills or with going green.

I dont believe it !!!!!!

This is what I see:

200 amp coming in (panel filled), a 100 amp sub panel (panel filled), and another 100 amp sub panel (panel empty). Both sub panels feed off from the 200 main panel.

What you have is a 200 amp service, not a 300 amp service.

A 300 amp service has a 300 amp meter base or 300 amp main disconnect which then typically directly feeds to a 200amp panel and directly feeds to a 100amp panel.

These panels are not otherwise connected.

You description indicates you have a 200amp service with a 100amp subpanel feeder.

If you want to verify what you have, ask the electrical inspector who approved the installation.