You're confusing voltage and current and power (watts).

Originally Posted By: carp

Power adopters are basically "low voltage transducers" say from 15 amps down to the device 5 amps and would fry first but how much gets through to the device is a question - thats the job for the surge protector
A lot of people get that confused. Actually the power adapters don't change amps, amps are drawn by the device that's being powered. Adapters change the voltage, so theoretically since there is less voltage there are more amps available. Using a 15 amp circuit at 120 volts you can pull 1800 watts of power before blowing a breaker, IxV=P, amps x volts = watts, so at 12 volts it's 150 amps that can be drawn from the line, 1800 watts = 12v x 150 amps. Of course no IC can carry 150 amps, in electronic land that's an LOL, LOL.

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Keep in mind that the ground wire is basically there for protection from electrocution and possible fire , it gives the voltage an easy route back to the ground - grounding does nothing for surge protection at all ,
It has everything to do with surge protection. In a good surge protector the surge, the over voltage, is sent to ground, not neutral. It's not a current surge, it's a voltage surge. In theory there is more current available since the voltage is higher, P=IV, but there needs to be equipment to pull the current to trip the fuse, sometimes it happens, mainly on circuits with motors or a lot of lighting. By the time the fuse trips it's to late though, the damage is probably done. Voltage is 60 hz, surge protectors generally stop surges within 100 hz or more, so the over voltage can't get to the equipment.

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In short the 3rd prong on a surge protector only protects you from electrocution does absolutely nothing to protect your devices . Thats the job for the built in trip fuse to detect a surge
No, the job of the breaker is to protect against too high of a current draw from the circuit, not an incoming voltage surge. But again at the point it trips it's too late anyway. Like mentioned above the excess voltage can cause the circuit to draw more current if devices are attached, but a circuit with no load will not blow even with a voltage surge of many times the rated 120/240.

Edit - Re: the third prong. It will send any voltage on the case to ground, protecting you from electrocution, but if you grab a hot wire and and it has a path to ground through you the third prong is useless.


Edited by Reboot (07/15/09 07:31 PM)