You can put up to 40 lights (based on 50 watt light) on a 20 amp breaker.
can you run lights on a 20 amp circuit? Lighting fixtures can be put on any 20 amp circuit except those that are required by code not to have lighting fixtures (washer, kitchen small applicance, and dedicated equipment circuits).
One may also ask, what can a 20 amp circuit support?
A 20 AMP circuit at 120 volt (at 80%) will hold 1920 watts for long periods. It would be possible to operate a 1200 watt coffee pot and even a 600 watt can opener, but not a 1200 watt coffee pot and a 1500 watt microwave oven.
How many watts can you run on a 15 amp circuit?
1,800 watts