It's 120V. Pushing 20A continuous through that kind of wiring is less than ideal.
First of all, let's assume less than ideal conditions so base our calculations on 115V. 2,500 watts is going to be 21.7 amps; assuming a continuous load (which is pretty reasonable for a whole house) is going to need a breaker and wiring that's rated for 125% of that, or 27.2A.
That means the supply needs to be #10 wiring and should be fitted with a 30A breaker at the disconnect. A temporary power tap is not a suitable disconnect. And I highly doubt it's got 10 gauge wiring.
