On 19 Nov 2006 16:42:17 -0800, "gus" wrote:

We are putting light bulbs on a large outside tree in a city park. We
have six 100 foot strings of 100 C-9 lights. We have two 20 amp GFI
circuits available. I plan to put 300 lights on each circuit. My math
shows 2300 watts available and C-9 bulbs use 7 watts. This comes to
2100 watts. I will use 12 guage extension cords. The light strings
and bulbs are commercial grade. This all looks good on paper, but I am
worried because there is not much room for real world error. Does
anybody have experience with this many lights? Wasn't there a movie
about a guy causing a large scale blackout when he threw the switch on
his house decorations?

I think I remember that from "National Lampoon's Christmas Vacation"
and the blackout ended when someone at the power plant threw a switch
labeled "Emergency Nuclear Power".

That was followed by someone saying "Don't look directly at the
house".

I don't want to be that guy. Any help you can
give me would be appreciated.
Thanks,
Gus

I have used 300 around my house, but that was divided among 3 circuits
(shared with other lights). I consider the load to be 6A per 100.
That's a little safety margin.

18A load from lights might be too high for one circuit, considering
the extra current drawn by lights when they're cold.
--
36 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"I have found Christian dogma unintelligable. Early
in life I absented myself from Christian assemblies."
-- Benjamin Franklin