I am assuming that the 2000 watt lamp is pluged into a duplex receptacle. If that is the case, you are in violation of 210.23(A)(1) which limits the load that can be drawn from a other than single receptacles. the load of a cord and plug connected load is limited to 80 percent to the rating of the branch circuit, in your case, 16 amperes maximum for a duplex GFCI receptacle.
