More than 120V harmful?

[VirtualLarry]

I was just checking my Kill-A-Watt, and now the AC voltage is reading 122.6V. Is this higher-than-normal voltage dangerous for anything?

Would it be dangerous if I were using a non-APFC PSU? (The ones with the 120/240V slider switch in the back.)

 

[nutxo]

I think I read 115/125 was normal

 

[BoomerD]

YES!! You should send your computer to me immediately!!



My line voltage fluxuates from about 118 to 122 on a regular basis.

 

[imagoon]

In the United States and Canada, national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 to 126 V (-5% to +5%).

My math instinct says 122 is between 114 and 126.

 

[Zap]

My math instinct says 122 is between 114 and 126.

If it isn't your Spidey senses, then plz turn in your geek cred card at the door.

 

[SparkyJJO]

Everything you have is going to explode.

 

[Modelworks]

The killawatt isn't accurate for AC voltage measurements either. You need a True RMS meter for that. 110 - 125VAC is fine. Providing AC power to homes is VERY tricky because as people turn on and off devices the load changes and so does the voltage. To compensate utilities have to switch in and out generators constantly to keep the power stable. If they are too slow in adding a generators output you get brown outs, too many generators and you get surges. I have never seen AC exceed 125.5 volts in all the time I have been in electronics, the utilities are pretty good at what they do.

 

[stahlhart]

It could be potentially harmful if the device in question were much older, say, 40 or 50 years old, when it was designed with the expectation that the line voltage in your home was more like 117VAC. The higher voltages we have today can put older power supply components such as step-down transformers under greater stress, to the point that a fire hazard is possible. Some folks running vintage gear have taken to putting bucking transformers in the primary circuit to drop the voltage a bit.

But a PC power supply? Nah.

 

[Gillbot]

The killawatt isn't accurate for AC voltage measurements either. You need a True RMS meter for that. 110 - 125VAC is fine. Providing AC power to homes is VERY tricky because as people turn on and off devices the load changes and so does the voltage. To compensate utilities have to switch in and out generators constantly to keep the power stable. If they are too slow in adding a generators output you get brown outs, too many generators and you get surges. I have never seen AC exceed 125.5 volts in all the time I have been in electronics, the utilities are pretty good at what they do.

No, they can regulate right at the sub for smaller demand changes. Larger ones require changing turbine output or bringing turbines on/offline as required. Much of it is now completely automated as well. Target voltage will also very by delivery point. Keep in mind that many stations are generating hundreds of thousands of volts. They are not "tweaking" their signal to maintain 120v at your house. That's to be regulated at your local switchyard after it's been stepped down to more reasonable levels.

 

[Modelworks]

No, they can regulate right at the sub for smaller demand changes. Larger ones require changing turbine output or bringing turbines on/offline as required. Much of it is now completely automated as well. Target voltage will also very by delivery point. Keep in mind that many stations are generating hundreds of thousands of volts. They are not "tweaking" their signal to maintain 120v at your house. That's to be regulated at your local switchyard after it's been stepped down to more reasonable levels.

Here they use autotransformers to maintain the voltage, but that is being replaced by a new substation that is going to be DC power based, only converting to AC when the power exits. I have an uncle who is the lead engineer and he was saying it is part of a DOD mandate to be able to add redundancy to military bases without the need for generators. All I could think was that has to be one hell of a bank of batteries. My uncle laughed and told me to invest in lithium mines , that the one project alone he is doing could make me rich.

 

[BladeVenom]

Doesn't your UPS have a voltage regulator?

 

[LiuKangBakinPie]

Voltage is mostly a measurement of 'potential' energy available, not necessarily how much is actually used. Measure what is actually drawn by your appliances Amperage

UPS devices can only deliver about 60 percent of their VA rating.

 

[PreferLinux]

Neither voltage or current on their own represent power or energy in any way. Power is represented by voltage multiplied by current. Energy is represented by power multiplied by time. Also, voltage is nothing to do with potential energy in any way: it is more like water pressure. It is known as "potential difference", but that is different to potential energy.