Building a temporary circuit breaker.

Building a Temporary Circuit Breaker
By Daniel Harvey

Concept & Use:
Although this is not a sweep tool, it is a very simple and convenient troubleshooting tool. It has been used in similar form by several manufacturers for protecting feeder legs in a short circuit situation.

Description: It is a simple 7-amp fast self-resetting circuit breaker. I prefer the glass bulb types because they give a visual flash every time they are tripped, but any self-resetting breaker will do. I am using the breakers from Jerrold Starline bridger legs.

Construction: Refer to the sample drawings below: Just take your breaker and put your own test leads on it. You can use probes or alligator clips or you can solder the leads to a blown fuse to plug directly into your amplifier.

I generally use this on feeder legs only because you should never see this much current draw on any single feeder. You can, however, use it on trunk if you are sure that the normal operating current of the trunk leg does not exceed the current rating of the breaker--otherwise, you could be chasing your tail !

This tool will keep you from blowing a handful of fuses while tracking down the short and you won't have to subject your expensive digital voltmeter to extreme currents while checking current draw.

In Addition: It is nice to have a helper on this type of trouble so you won't have to drive back and forth to see if the short is gone.
You can have a man keep an eye on the breaker while you go down the street to eliminate suspected components. Or, you can get some cheap 2-mile radios and tape the breaker close to the mic on one and tape down the transmit key, then you can hear the breaker click every time it trips. You won't have to wait on it to trip--the breaker trips on and off about once per second--so, you will have a constant tick-tock-tick-tock-tick sound.

Happy sweeping----
Daniel Harvey

Here are two sample drawings: