Basic electrical theory tells us that power (watts) = potential (volts) * current (amps). Alternately, amps = watts / volts. So, given a 1 amp power supply, it's going to use about 110 watts at 110v AC. A 250 watt PC power supply will draw 2-1/4 amps, and a 1000 watt power supply will draw 9 amps. Amps are cumulative, so on a normal household 15 amp circuit you could have a dozen 2500's without overloading the circuit. Add a Catalyst 5500 to that rack, and you've overloaded the circuit. Keep in mind that these power/amperage ratings are usually maximum ratings, often the power requirements are less than that, once the device is up and running. Startup current is high, then it settles out. In my old apartment, if I turned on both power supplies to my Cat5k at the same time, sometimes the 15A breaker would trip. Note that typically houses are wired with lighting and outlets on the same circuit, so having several lighting fixtures with 100w bulbs will add to the electrical load on that breaker. If I waited a minute before turning on the second supply, life was grand. In my new place, I ran a separate 20 circuit to the spare bedroom outlets, so that I wouldn't have to worry so much about my rack o'gear. I also run all the gear through a UPS, so that the occasional brown-outs don't worry me, as much a before. Running a half-dozen devices off a power strip plugged into the UPS probably isn't the best solution, but I like it better than just the power strip. Note also that the UPS comsumes power, add that to your total current/power draw. As an aside, I also run my TV off a UPS. During an outage last fall, I noticed that several of the neighbors were on the sidewalk, trying to figure out why the game was still on in my apartment, and the rest of the building was dark. :) -jon- --- Richard Chang wrote: > Just a quick question for those of you who have dealt with a home lab > before: > > Currently I got 5 2500, 1 2926 and 1 4000 and just realized that I > probably > want to make sure that I don't blow my circuit-braker off once I turned > all > these on at the same time. According to Cisco's site, the 2500 would > take > roughly 1 amp, 2926 would take 3 amp while I could not find anything for > the > 4000( it only says 200 W). So I am just curious whether anyone has done > any > study on the power consumption of these various Cisco gears. > > BTW, stupid question, anyone know how many amps would a normal desktop > PC take? > > Thanks! > > Richard __________________________________________________ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=8081&t=8081 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
