Timer with less than 1-minute intervals?

[powerboy]

goto your local hydroponic store and ask them for a "green air cyclestat"
this little beauty is exactly what your looking for, its grounded, and if memory serves me correctly, rated for 15 amps 110V
it allows you 5 seconds to 30 min of "on" time and 7 minutes to 8 hrs "off" time between cycles

itll run ya about $100 cad.. hope this helps