I in the process of installing lights. These Light uses 208v at 1.35 amps each with a 250w load, how many lights can I install onto a 20amp beakers that is connected to 208v?

Where are you using 208V lights? I assume not in a residence.
This does make a difference.

I in the process of installing lights. These Light uses 208v at 1.35 amps each with a 250w load, how many lights can I install onto a 20amp beakers that is connected to 208v?

Since you are using 208V, I am going to guess that you are installing these lights in a commercial environment.

Given that there is a 10 "Outlet" circuit restriction (NEC imposed) your answer is 10 lights per 20 amp circuit.

Also, if this is a commercial environment, then only licensed electricians can do the work, also a requirement of the NEC.

208V is nothing to fool around with. It will literally kill you in a heartbeat if you make the simplest of mistakes. Work on the light circuits must be completed without the circuit being energised.

Given that there is a 10 "Outlet" circuit restriction (NEC imposed) your answer is 10 lights per 20 amp circuit.Don, can you tell me where you heard of this imaginary code?

You can have up to 3300 watts on 208v, 20 amp breaker. Lighting is usually considered a continuous load ( 3hrs or longer) and can only us 125% of the breaker amperage. 20 amp divided by 125% = 16 amps. 16 x 208v = 3328 watts

You can have up to 3300 watts on 208v, 20 amp breaker. Lighting is usually considered a continuous load ....... in a commercial environment...
Which I would also consider this.

IMO this should be done by a qualified electrician. Commercial electrical work is not a DIY/handyman kind of thing.

Don, can you tell me where you heard of this imaginary code?

Stan,

You are correct, as usual. I went through the 2008 edition and the 2011 edition of the NEC, no joy.

I also went through the following books.

Thanks for your help. I got the 10 lights to one 20amp breaker, but just wanted a clarification. Right now we have 30 lights running on 6 20amp breaker. I just needed to add 5 more lights to certain section of the building.

Thanks everybody.