One 30 ampere, single phase, 240 volt branch circuit supplys only six electric space heaters. Each heater is rated at 1000 watts. What is the maximum number of these space heaters this branch circuit may supply?

One 30 ampere, single phase, 240 volt branch circuit supplys only six electric space heaters. Each heater is rated at 1000 watts. What is the maximum number of these space heaters this branch circuit may supply?