Can a 250v kettle cable power a 230v power supply?

redped

I'm not sure what the voltage has to do with anything, as it's current that kills rather than voltage. All I'm doing is saying to the OP that if they're not confident installing a PSU, they should go to a PC repair shop instead.

m5rcc

Talking of PSUs, does anyone know a suitable replacement for the dead PSU?

ukcarper

redped wrote: »

I'm not sure what the voltage has to do with anything, as it's current that kills rather than voltage. All I'm doing is saying to the OP that if they're not confident installing a PSU, they should go to a PC repair shop instead.

I’m not sure that’s true I believe it’s a combination of both otherwise I would have been killed years ago.

esuhl

redped wrote: »

I'm not sure what the voltage has to do with anything, as it's current that kills rather than voltage.

The voltage is being used to indicate the power source. Most people are more interested in avoiding pain/death than they are in understanding whether it's the voltage, the current or both that cause tissue damage.

The average person is likely to know that mains power is rated at 230V and the DC voltages inside a PC are 3V, 5V or 12V. They are unlikely to know how many amps of current a particular device draws. Therefore, when referring to a power source, it makes more sense to distinguish by commonly-known voltages than widely unknown and device-specific currents.

redped

So you guys are saying the 12V lines used inside a PC are safe to touch when live? Given that the PSU referred to by the OP lists 12V DC outputs of up to 18 amps (see here), I'd rather you touched them than me. A DC current as low as several hundred mA can kill a human, no matter what voltage it's at, whereas static electricity can be several kV and won't kill, due to the very low current.

We only got side-tracked into this when I said that electricity can kill, and macman said "I don't see how it could be lethal, since a PSU is only outputting 12V - hence me saying the voltage isn't the killer. All of a sudden we're back to basic principles of electricity!

Bottom line is - always respect electricity, no matter what voltage you're working with. If the OP's not confident about replacing a PSU, they should get someone else to do it for them.

fwor

redped wrote: »

So you guys are saying the 12V lines used inside a PC are safe to touch when live?

Yes, they are, and they are correct.

Are you aware that a 12V car battery can deliver several hundred amps into a load such as a starter motor, yet you can touch both terminals by hand without any ill effect?

The reason why is that the human body has too high a resistance for 12V to cause a high enough current to flow to cause any harm, or indeed even be felt (unless you use your tongue!).

barak

Ohm's law

V = I x R
or
I = V / R
Current [Amps] = Voltage [Volts] divided by Resistance [Ohms]

As fwor says the human body's resistance is very high - perhaps 100,000 Ohms

So 12 Volts DC / 100000 Ohms gives a current of 0.00012 Amps or 0.12mA [E&OE!]

Nevertheless, that's not to recommend that anyone touches any live wire.

cit_k

Besides, you wont be touching any live wires, or wiring anything up incorrectly seeing as its all plug and play really, and all connectors just plug into matching sockets.

Not only that, why on earth would you be doing the work with the mains supply plugged in?

ukcarper

I have touched 50v live feeds many times and not felt a thing and these can supply a lot more than 12 amps. But as barak says the amount of current they do supply is depended on resistance.

As barak says it’s not recommend as the resistance of your body varies if you are sweating for example.

macman

redped wrote: »

So you guys are saying the 12V lines used inside a PC are safe to touch when live? Given that the PSU referred to by the OP lists 12V DC outputs of up to 18 amps (see here), I'd rather you touched them than me. A DC current as low as several hundred mA can kill a human, no matter what voltage it's at, whereas static electricity can be several kV and won't kill, due to the very low current.

We only got side-tracked into this when I said that electricity can kill, and macman said "I don't see how it could be lethal, since a PSU is only outputting 12V - hence me saying the voltage isn't the killer. All of a sudden we're back to basic principles of electricity!

Bottom line is - always respect electricity, no matter what voltage you're working with. If the OP's not confident about replacing a PSU, they should get someone else to do it for them.

You are missing my main point, which is that you do not work on a live supply when replacing a PSU.
A PSU is a user-replaceable part, assuming basic skills. Obviously if you are incapable of changing a plug, you'd probably not want to tackle a PSU.