Tuesday, February 20th 2007

I had some sort of a debate lately regarding overrated power supplies and their necessity. And when I came to browse through the websites that I read on a weekly basis afterwards I found a very interesting article about how to prevent electrical fires caused by draining too much power from the wall outlets. Though the stated formulae, calculations and hardware devices are dedicated to the '110V world' only the theory behind is applicable to the rest of us with ease.Source: OverClockers.com

#1
...No offense but how is this news?
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#2
it isnt. and its a load of garbage. every house requires circuit protection via fuses or breakers that trip far beyond the maximum of the circuit where there could be problems. Also, where did they come up with this crap that a household outlet will drop to 98volts when loaded?
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#3
WeStSiDePLaYa said:
it isnt. and its a load of garbage. every house requires circuit protection via fuses or breakers that trip far beyond the maximum of the circuit where there could be problems. Also, where did they come up with this crap that a household outlet will drop to 98volts when loaded?
Actually that's quite true. It is true for the 240V world anyway, just take your multimeter and measure the power in the power outlet at home, it most likely is around 115V or 240V (depending on where you are) Try the same in heavily loaded situations, at the office/school for example, often the output is slightly lower there, normally this isn't a problem though.
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#4
cool. thanks for the info.
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#5
***** SERIOUS HEALTH WARNING - PAY ATTENTION!!! ******

@dan,

This is TERRIBLE if you discover this. For a local voltage drop to occur, there would have to be a voltage drop at the last transformer (street or town level). This is not possible.

The only occasion you can experience 98v at the socket is when a voltage DIFFERENCE is measured at 98v. This can occur is if there is a near FULL load at the socket... and the house is serving 115v, but the WIRING between the supply and the socket is "losing" 17v from the 115v.

THIS IS VERY VERY DANGEROUS. It suggests that a high current is being transmitted through thin wires designed for low current. The resistance is too high. There is SIGNIFICANT probability of the cables over-heating, arching, burning, shorting, causing one or more of:

1./ Fuse cut off (hopefully)
2./ Cable burn out within the walls or socket (will need to recable house)
3./ Major fire (will need to rebuild house).

IF YOU EVER MEASURE 98V at the socket (115v countries) or only 200v at the socket (230v countries), then SWITCH OFF IMMEDIATELY and call an electrician to recable the house.

The National Electric Code (USA) recommends a 5% MAXIMUM before risk. This means a 120v sully can go to 114v, or a 115v supply to 110v MAXIMUM. http://www.psihq.com/iread/faqvolt.htm

In Europe the maximum allowance is 2.5%
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#6
The sky is NOT falling!

Yes, house voltage dropping below 98V happens on occasion esp. in CA. in the Summer. When voltage drops / amperage draw goes up on a circuit under load then the circuit breaker is supposed to open the branch circuit when it has sensed a 15a load on a #14 wire or 20A on a #12 wire circuit.

A Uninterruptible Power Supply (UPS) system of about 750 watts will prevent your performance computer from dropping below 104V or above 136V. A UPS also cleans up a lot of the electrical noise (RFI) on a computer ac typical 115V circuit. My 1200 watt APC ups cost about 130. It gives me about 45 minute of back up time. :toast:
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