I made a big error today on wiring a new circuit. I pulled 2 cables (for 2 circuits) back to the consumer panel and then connected the wrong cable. The cable that I connected was stripped at the other end but not yet connected to anything. When I went to inspect it, I tugged on it and there was one short pop/spark/flash. I realized my error and went back to the consumer panel - the breaker to that circuit had NOT tripped. I am concerned as I thought that any arcing should immediately trip the breaker. Do I have a faulty breaker? Is it possible that my grounding is insufficient? Is there any way to test my breakers (without intentionally setting up s short circuit!)?

A few details - the cirucit was 10/3 cable with a 30A breaker. The wires in closest proximity were the black and the ground.

I don't think the breaker is bad, is possible, but when the short occurred, the arc burns or melts the metal quickly, clearing the short, and if the short was not definite, the breaker saw it as a load, and allowed current to flow until the short did clear.

There is no method to test a small breaker in the field, and is not practical to have a testing firm test a CB just for a routine event. If there was a fire involved and a CB was in question, then a testing firm would be hired to determine if a CB contributed to the fire.

What you described is a typical high resistance short that cleared in a few cycles before the CB could react.

Hope this helps and makes sense.

It makes perfect sense and I will sleep better at night. Thanks!