I've been wanting to install some floodlights in my backyard for some time. Recently I bought some floodlights that I thought would do the job. I purchased 2 sets of lights, each set comes with 2 lights. Each light is a 100 W halogen bulb, for a total max output of 400W.

I wired the lights through my attic, and daisy chained one to the other, such that I have wires going into the first light, out of the first light and into the second light. The 14-2 wire I have terminates at the second set of lights.

I wired them into an existing circuit that currently serves a couple of outdoor wall outlets. These outlets are not being used at the moment.

After I wired them (white to white, black to black, ground to ground) and hooked them up to the switch, I turn the breaker back on. I then hit the switch to turn on the lights. The first time, they lit up the back yard nice for about 5 second, and then the breaker tripped. So I reset everything, and double check all my wiring and made sure these were the only items drawing power from the circuit. I then reset the breaker and turned them on again whereafter I here a buzz for about a half second, and then the breaker trips.

Here's my set-up in a brief summary.

15 AMP breaker
14-2 Romex
light switch wired in tandem with existing circuit
feeder line from the switch to the first set of lights
feeder line from the first set of lights to the second set of lights
Romex terminates at the second set of lights.

Any ideas? I already tried bread.

 

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Well if you tried bread already, I'm out of ideas...

 

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I'd guess that you need to wire it to a 20 amp breaker.

 

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You could have a bad fixture. Try hooking up each set of lights individually and see if a single set will pop the breaker.

 

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Old dry rot breaker? (Note, I didn't run any math on your layout)

For a 20 amp breaker the entire circuit on that system needs to be 12 gauge not 14.

You must have a short in one of the fixtures, I am assuming you wired them in parallel vs series.

Disconnect one light at a time to diagnose which fixture is causing the short.

 

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if everything is unplugged, then I would be running 400 W max, right? a 15 amp w/ 120 V and am 80% efficiency should amount to a max allowable of about 1440 W, right? so the amperage is not the issue.

Hyper, I've wire them like so, where the | represents a three strand wire.

Breaker
|
|
|
Light Switch
|
|
|
Fixture One
|
|
|
Fixture Two

 

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.

 

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Wait, wait, wait! What kind of bread was it? French? Sourdough? Wheat?

 

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It was Rye bread.


So I've checked for noticeable shorts in the light fixtures, and I don't see any.

But here's some interesting news... after undoing the fixtures, and then putting them back in, I'm able to turn the flood lights on... however, whenever I turn them off, the circuit blows.


I turn on all the lights on the circuit, and then I turn on the flood lights, and everything works great... at least 15 minutes great.
I then turn off the flood lights and the circuit blows.

I turn off all the lights on the circuit, and then I turn on the flood lights, and everything works great... another 15 minutes great.
I then turn off the flood lights and the circuit blows.

That's an interesting thing now, any ideas?

 

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