Fuse keeps blowing on Christmas lights


Old 12-05-04, 04:19 PM
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Fuse keeps blowing on Christmas lights

I have 7 of those 25 bulb (type C7) Christmas light strings strung together that I've used on the exterior front of my home for 7 years. I put them up for Christmas and take them down again. Now for some reason the string keeps blowing the fuse in the plug of the first string (the one that plugs into the extension cord). Replaced the fuse - didn't work. Replaced the string - didn't work. Replaced all 7 strings - didn't work. I can't figure out why it keeps blowing the fuse. I've tested the circuit with a circuit tester and it is showing good. The fuse blows immediately. I drape the strings over hooks that I permanently installed years ago. I don't use any staples. With a complete set of new light strings there shouldn't be any shorts (besides, wouldn't the GFCI trip if there was). The lights draw .98 amps so I should have plenty of current (7 strings is about 7 amps). The circuit is my 15 amp GFCI garage circuit and I do have some other stuff plugged in like a refrigerator and overhead florescents but I've had that for the past 7 years so I don't think that could be causing it. I also tried unplugging the fridge and turning off the florescents and it didn't make any difference. Besides, would too much stuff cause a fuse to blow or would it trip the breaker instead. Anybody know what is going on with this?
Old 12-05-04, 05:08 PM
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Have you always plugged all seven strings together in one long string. Every string of lights I've ever seen tells you that three is the most you can string together. Each string takes about one amp, but there is a 3-amp fuse in the beginning of each string. Each string must carry the current not only for itself but for all downstream strings as well. The 3-amp fuse is what limits you to three strings in one line. Please don't be tempted to increase the size of the fuse. It's what keeps the wire from catching fire.
Old 12-06-04, 07:08 AM
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Ohhhh.... That makes sense. My strings actually have 5 amp fuses in them (rated for 5 amps I should say and I always replace them with 5 amp fuses). I've always strung the 7 together but never had a problem till now. Guess I will need to split the strings into separate strings. I guess I've been stumped by this because it use to work fine with 7. Thanks for the advice. I've felt like Chevy Chase in Christmas Vacation with this problem. My wife and daughter teasing me about it didn't help either.

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