Electrical – Wires Physically Move When Breaker is Enabled

electrical

I was working on the wiring in an outlet of a home from the mid 1950s. This kitchen outlet connects a switch to the garbage disposal. I connected the live wire from the circuit breaker directly to the wire leading to the appliance and then had the circuit breaker switched back on. At that instant, the wires physically moved a noticeable amount. I repeated this, and the result was the same.

What explanation can there be for the wires moving when the power at the breaker was applied? (Because of how the wires are routed, I don't think the disposal torque pulled the wires, but I could be wrong.)

While I am an electrical engineer, and can sort out connections fairly easily, this has me concerned.

Best Answer

Is the disposal starting? If the disposal is stuck it could be drawing locked rotor current many times the circuit breaker rating causing the wires to jump even if it is starting a motor normally draws 3-5× its FLA or full load amperage for a fully functional motor. This combined with possibly a longer than normal length distance to the first staple it could be somewhat normal. If you hacer ever watch welding leads jump my big welder when on high the leads may jump a couple of inches with a heavy or thick rod. To further explain your home circuit breakers are inverse time they will hold 10x there rating for a very short time 150 -200 amps in that 14 or 12 awg wire will cause to jump. Hope this helps.