Comment on Prototype of RTX 5090 Appears With Four 16-Pin Power Connectors, Capable of Delivering 2,400W
InverseParallax@lemmy.world 1 week agoAmps are voltage over resistance (I = V/R), volts absolutely matter, the human body has a decent resistance and the higher voltage helps burn through that.
ExcessShiv@lemmy.dbzer0.com 1 week ago
There’s a reason we talk about lethal current and not lethal voltage…30mA can kill you, even at something ridiculously low as 9V, but 5-10kV will not necessarily kill you, e.g. fences for horses will not kill you if you’re electrocuted by them because there’s basically no amperage. Voltage is not the determining factor in lethalness.
mriguy@lemmy.world 1 week ago
In most household shocks, you touch a conductor, and you are the resistor to ground. Your resistance is independent of the drive voltage, so if you touch a 110V wire, the current will be half of what you get with a 220V wire. So the voltage determines the current, and this the lethality.
There’s lots of other factors that go into the effective resistance like the amount of moisture on your skin, what shoes you’re wearing, and what the floor is made of, etc, but in all cases twice as much voltage will cause twice as much current.
It’s a bad idea either to go touching live wires either way, but the rule of thumb I heard was was that a 110V shock usually won’t kill you and 220V shock usually will.
ExcessShiv@lemmy.dbzer0.com 1 week ago
That’s completely incorrect though. I’ve been shocked by 230VAC at least a dozen times, if not more. And the fuse for the circuit absolutely should not be the limiter, the RCCB should trip WAY before the main fuse.
mriguy@lemmy.world 1 week ago
While that certainly SHOULD be the case, in the US at least while RCCBs (we call them GFCIs) are generally required in wet areas and perhaps for new construction, in most older houses the majority of circuits don’t have any sort of ground fault protection other than the fuse/breaker. In my current house we have them on only two outlets - one in a bathroom and one in the kitchen.
InverseParallax@lemmy.world 1 week ago
There is no current without voltage, what you’re saying makes no sense.
Current is voltage over resistance, you get as much current as you have voltage, unless there’s an artificial effect limiting voltage, like a voltage regulator or zener diode or just fet.
When you say ‘it’s the current’, that electric fense has x volts before you touch it, and the fact that it doesn’t kill you means either the voltage is too low to produce a decent current in your body, or, there’s a voltage regulator/limiter that means when you touch it the voltage drops to some lower level, which I could calculate using the nominal resistance of the human body and the voltage of the fence.
In a way, the output impedance of whatever is driving the fence determines how much the voltage drops under load.