to calculate the amount of amps your breaker needs to be ,you divide your 2000W by the voltage of your outlet (US is 120 volts) (UK is 240) that will give you the amount of amps you need.... but if you have a 50 amp breaker.... you wont need to change them
2000W/120volts=16.66666 amps.... so a 20 amp should also be fine.... but BE CAREFUL WITH ELECTRICITY!!!!!! IT KILLS..... DONT DO YOUR WIRING UNDER THE INFLUENCE !
(if you have a 20 amp breaker, be careful not to go over the limit it could start fires)
hope it helps
I<3