Should I be concerned?

A friend was wiring a subpanel for me last night. In the main breaker box, things were kind of tight so he had to make space on the neutral bar and ground bar for the #6 wire I brought into the main panel.

He began to unscrew one of the neutral screws containing an active circuit when it sparked. I asked him to turn off the main breaker (something he hadn't done), but prior to turning it off, I went inside to tell my wife to shutdown PC's (there was no additional sparking at this point, to my knowledge).

My hall light was "pulsating" - getting dimmer and then brighter although I'm not sure the "brighter" was anymore than normal illumination. I headed back out to tell my friend about the effects of the light and he retightened the neutral. In addition, a 20amp breaker was off in the box (I don't know if it had tripped or he turned it off and I don't know if this was the same circuit as the light).

We then shut down the main, connected everything and turned it all back on.

Everything seems fine. The lightbulb (60w) still works fine, I didn't smell anything downstairs or upstairs, and I've done a cursory examination of the wires in my attic and don't see anything out of the ordinary.

Could have anything (wiring) been damaged? If so, I would suspect I would have some indication of any damage almost immediately. Correct? Should I have any lingering concerns?

Thanks in advance for any info.

 

Your friend is lucky. Once you disconnect an active neutral, that wire has 120 volts on it. Enough to cause damage.

Although it is theoretically possible that sensitive electronics could have been impacted by the voltage fluctuations, it seems unlikely. I think you got off scott free. Rest easy.