110V/125V = This is the standard household style plug. Each circuit can provide up to 20 amps/2000 watts (typically around 15amps or so). Most electrical needs will fall into this category. NEMA refers to this style connection as 5-15P.
Heatlamps: 1 heatlamp per outlet. A heatlamp & any other piece of equipment will blow fuses for the entire row of vendors!