wiring....

[inline 6]

getting ready to add outdoor lighting. I am putting up 8, fixtures with 50w bulbs in each. I want to add a breaker and switch just for this. I know how to do the wiring. My question is what gauge or spec of wire should I use? Is there a formula for this kind of thing?

[93smokinsnakeSVT]

20 amp breaker with 14 guage wire should be perfect for that

[slyhog22056]

How many 50 watt bulbs in each fixture????
Current = power (Watts) / Voltage (120 or 240)

www.sengpielaudio.com/calculator-ohm.htm

[RuStYpNuS]

20 amp breaker with 14 guage wire should be perfect for that

LOL wrong sir

pm me for more info

15a - 14/2 romex Max Ampacity Rating
20a - 12/2 romex Max Ampacity Rating

50w x 8 = 400w/120v= 3.3 amps

15a circuit and 14/2 would be perfect. If by chance your going to be exposing any of the wire then buy 14/2 UF cable as its uv resistant and weatherproof.

[inline 6]

LOL wrong sir

pm me for more info

15a - 14/2 romex Max Ampacity Rating
20a - 12/2 romex Max Ampacity Rating

50w x 8 = 400w/120v= 3.3 amps

15a circuit and 14/2 would be perfect. If by chance your going to be exposing any of the wire then buy 14/2 UF cable as its uv resistant and weatherproof.

Ok, so a 15a breaker is ok. I already have a roll of 12/2 outdoor rated. Will this be ok?

[RuStYpNuS]

12/2 is fine. you just never want to put a bigger breaker on a wire thats not rated to handle the max ampacity of the breaker

here is a useful chart
http://www.cerrowire.com/default.aspx?id=46