electric usage for Christmas Lights

[ejs1097]

I'm hanging Christmas lights for the first time this year. I have 1 circuit with an outside recepticle. It's a 15 amp circuit.

If the Xmas lights say 120V 60Hz and 0.324A.

At 110 V a 15 Amp circuit can carry 1,650 Watts

Watts= 110*.324= 35.64 watts per strand

Let's say I plan to hang 10 strands of lights. That means I'd be using 356.5 Watts of power, well within the range.

The lights of course say not to chain more then 3 strands together. As long as I do that, I should still be able to run them into the same circuit.

Is this correct? it's getting somewhat confusing.

[Tom Miller]

Yep, that's right. But, there's really no need to convert to Watts in the first place. Just add up the current of each strand, and compare to the 15A max of the circuit. Leave plenty of headroom, though (i.e. >=20%, which would make the max ~12A).

Regards,
Tom

[TheRic]

If there is anything else on that same circuit you would have to take that into account also.

[linear]

The lights of course say not to chain more then 3 strands together.

The way I understand it, that's a requirement for UL listing.

You may want to look into LED Christmas lights. Wal-mart is carrying some pretty good ones this year for not too expensive. They are a premium over the mini-lights, but if you get into large displays, the power savings can add up.

[Rslaugh]

The way I understand it, that's a requirement for UL listing.....

In all the new strings I've seen there are tiny fuses in the plugs which are sized to blow when you plug that 4th string of lights in.

[Wood_workur]

I have a dozen strands linked togethor with no problem, also powering a dozen lamps for ceramic houses, a couple computers, a train set, ect...

I doubt you will have any problems with power consumption.

[scorrpio]

The problem is not circuit overload, but wire inadequacy. Those strands use fairly light wire. A 24AWG wire has about 1.3A ampacity, so chaining more than 3 0.32A strands is pushing it and can overheat the wire. I order to safely chain 10 strands, you'd need 18AWG.

[ejs1097]

I was at Costco this weekend and they had 'commerical' grade lights with large amounts of lights on them. The box said you could chain 6 strands. So it would definetly be wire size.

Thanks for the confirmation. I wanted to check before I spend a few hours aloft on a ladder and haning all the lights before I find out I didn't have enough outside power to run it all. that would ba-hum-bug my season.