What it sounds like is an arc fault in the power cord. This type of fault occurs at broken wiring, loose connections and damaged insulation with bare wiring touching (grounded) metal. It is likely that your power cord has a strand or two that broke apart. When you turned the breaker on, the power arced or jumped the air gap between the broken wires. This is similar to what spark plugs and electronic lighters do. The resulting energy then burned a hole in the outer jacket.
As for your questions:
1. It's a good idea to turn off expensive equipment before cycling circuit breakers.
2. Breakers become more sensitive with time. There is a chance that the breakers "nuisance trip" but it is more likely that the breakers are simply protecting the circuit. Breakers can also trip when connection to the outlets are loose.
Two monoblock amps on one circuit is pushing it. Each amp I guess has a 750 watt power draw or 1500 watts total. If the breaker is 15 amps, it's too short; if it's 20-amps it should take it provided that the wiring is sound.
3. Anything is possible - but if your electrician gave the panel and wiring a looking over, then it's not the problem. If the lamps worked at the affected receptacle and you have a gaping hole in the power cord, it's not your receptacle or wiring, obviously.
4. To test your power cord, drop it in the garbage.
As an aside, this type of fault is what burns down houses. You drive a nail in the wall, nick the power wire behind it, and the resulting spark sets fire to the loose fill in the wall cavity. This is why the new electrical codes require arc-fault breakers for bedrooms - prevent this arc from forming in the first place.
As for your questions:
1. It's a good idea to turn off expensive equipment before cycling circuit breakers.
2. Breakers become more sensitive with time. There is a chance that the breakers "nuisance trip" but it is more likely that the breakers are simply protecting the circuit. Breakers can also trip when connection to the outlets are loose.
Two monoblock amps on one circuit is pushing it. Each amp I guess has a 750 watt power draw or 1500 watts total. If the breaker is 15 amps, it's too short; if it's 20-amps it should take it provided that the wiring is sound.
3. Anything is possible - but if your electrician gave the panel and wiring a looking over, then it's not the problem. If the lamps worked at the affected receptacle and you have a gaping hole in the power cord, it's not your receptacle or wiring, obviously.
4. To test your power cord, drop it in the garbage.
As an aside, this type of fault is what burns down houses. You drive a nail in the wall, nick the power wire behind it, and the resulting spark sets fire to the loose fill in the wall cavity. This is why the new electrical codes require arc-fault breakers for bedrooms - prevent this arc from forming in the first place.