Bought a new single strand of C-9 lights, 100 ft. To line the roofline, as I’ve done in the past. Strand comes with a 5 amp fuse.
As soon as I plug in the lights through a grounded extension cord, the fuse blows, lights out.
Tried another extension cord, another outlet, same result.
In the past I’ve had three separate 25 ft strands, connected together, with no problem.
Called the place I got them (Colorado). Guy assured me it was probably a bad strand and that the 5 amp fuse was adequate. He sent me a new strand off the show room that he said was working.
Another hour taking down the old strand, unscrewing, then screwing in the bulbs, plug it in and blows immediately again.
Except for the additional 25 ft and a single strand of lights, all is the same.

Calculates that at 7W per bulb and 100 bulbs = 700 W should require about 5.6 amp fuse (came with 5), I tried a 6 amp and still blew.

Any ideas would be appreciated!!

Merry Christmas!

How long and what gauge extension cord?

Same outlet?

I would try the strand on another circuit, first without and then with the extension cord.

Then if it still good, try the same way on the original outlet.

700w/120v=5.83a

Very close to 6a so if the bulbs are drawing slightly more or you house is below 120v coming in you might be exceeding the 6a fuse, definitely exceeding the 5a. Try running two extension cords. Hook up 2 or 3 to one and 1 or 2 to the other.

Also as the monkey stated if its a long run then you have to deal with voltage drop. The voltage drops the further you run wiring. So if the extension cord is 16awg, then the xmas lights are 16 or 18awg and plugged in a long distance from the panel to outlet to strings you can easily exceed 6a.

quote:

Originally posted by Skins2881:
700w/120v=5.83a

Very close to 6a so if the bulbs are drawing slightly more or you house is below 120v coming in you might be exceeding the 6a fuse, definitely exceeding the 5a. Try running two extension cords. Hook up 2 or 3 to one and 1 or 2 to the other.

Also as the monkey stated if its a long run then you have to deal with voltage drop. The voltage drops the further you run wiring. So if the extension cord is 16awg, then the xmas lights are 16 or 18awg and plugged in a long distance from the panel to outlet to strings you can easily exceed 6a.

This. I had a similar issue and my dad said to tie in another extension cord and my GFCI quit popping in the house.

quote:

How long and what gauge extension cord?

That was my problem the other day...
I blew my extension cord. I used a heavier gauge and they are working again.

Them thirsty l'il lights need a bigger straw to suck all them electrons.

Too skinny a straw, the straw collapses, and then it's lights out.

Thanks much guys! Great insight and think I’ve put your ideas together for a plan that will work.
Tks SigMonkey, you’re right, should’ve plugged directly into wall first off, make sure they work at all. Will then get a shorter length extension cord of heavier gauge wire. That should do it.

Merry Christmas!! Happy again

Are these LED lights ?

Never mind , I looked them up . C-9 is the old school bulbs .

They do make LED C9 bulbs, but if they're drawing 7W each they're not LED.