How many amps would you estimate a plasma tv using 400 watts might pull?
3, give or take. The main source of power consumption is the screen, so the draw is pretty much constant, but the 400 watt rating is probably a smidge high.
Amps are a different story, as a 500 watt amp that's only 50% efficient would draw 1000 watts at full power. But amps are seldom run at full power or anything close to it. At average listening levels they usually coast along at 10 to 20 watts.
Because one of the main reasons for them is plugging into different outlets, and that's very often the case when powered subs are remotely located from the rest of the electronics. As to being an 'annoyance', tell that to someone who can't get rid of the 60Hz noise that they create.
Oops, sorry, fly-by posting and did not make the connection. I was addressing the "risk of damage" issue he raised, not the level of frustration entailed trying to troubleshoot a ground loop (something I have done many, many times; the annoyance at home is nothing compared to the frustration of spending hours setting up for a live performance and then dealing with a ground loop 1/2 hour before performance! Or during, when the guitar player suddenly decides to move over and switch from pluggin in "here" to "over there" to be closer to the lead singer...)
"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
I just installed whole house surge...and 2 of the 3 electricians giving me estimates still recommended using outlet protectors too.
I have a subwoofer (400W RMS, 800W peak), amplifier 945W (135W*7), a wireless router, a DVR, a PS3 250W, and a CD player.....all 6 devices that I am planning to plug into a Monster Cable MP HT 850 Home Theatre PowerCenter (2590 joule rating with 1,875W limit).
I think a lot of people plug all or most of their gear to run off one circuit. You are never using all the max power of the gear's spec. I run 2 amp(250 watts), TV, cable box, BDP, avr, SUB amp all off a 15 amp circuit with no problem. The highest I have eve seen the power console/conditioner go was a 960 watts and amp never past 7. I spin off some of the other gear to a second circuit. A 15 amp circuit is capable of 120 volt, around 1800 watts. Unless you have gear that calls for a 20 amp circuit, you should be fine.