Favour please.

If you live in the USA or Canada and you can safely, with reasonable accuracy, measure your mains supply voltage and post the result it would be appreciated.

I understand the utility companies strive to maintain the 120VAC supply somewhere between 114VAC and 126VAC. I am curious to know the actual voltage.


Many thanks

Paul

At work it's 121 V. At my condo it's 125 V with the AC off, 123 V with the AC on. If I crank up my home theater I can get it to sag to 120 volts or so, though at that point I'm close to popping the breakers and I'm sure it's just a wiring issue. The mains voltage at the breaker stays at roughly 125 V +/- 1 volt at my condo.

This is in Clemson, SC.

120 would be the nominal voltage. Both extremes of commonly bad is 123, 118 volts. But for testing purposes 120V is where you would want to be.

I do appreciate 120VAC is where I want to be (hoping it would be a little lower) but:

2000W Power Supply + 240VAC 2.4kW Variac = Lots Of Money!

I was asking because here in the UK 110VAC power tools are used on building sites using an isolating transformer for safety. I have managed to lay my hands on a 2.5kW model. This means I could test power supplies at 110VAC and 230VAC. Would this be useful information for you guys in the USA and Canada (and anywhere else that use 120VAC)?

I have an OCZ 600W running on it at the moment. It's rated for 100VAC to 240VAC so in my opinion it is probably a better voltage range to test on.

What do you think?

Cheers

Paul

Here's mine taken just now...

Testing at 110V would be a low voltage for here. However it would demonstrate the PSU's ability of outputting the correct voltages at a low supply level. Your stated efficency would also be slightly lower then would be found in normal use. I say give it a test and see how everything works out.

Testing at 110, 120, and 130 V would show the ideal case and both extremes. If you've got the extra time in a review to do all three I'd certainly be interested in seeing how PSUs can handle it.

As has been mentioned, obviously 120V is ideal, but 110V testing could be relevant addition to any future reviews for the reason Praz mentions above. SPCR includes a small low VAC testing section in its reviews for example. [H] also performs load tests at 100V.

hmm 115

It's a fixed 230 - 110 VAC isolation transformer so it's 110VAC only I'm afraid.

I have had a look at other power supply testing methodologies and test voltages vary from one site to another. Most but not all use 120VAC only.

So it's 110VAC and 230VAC for OCC. Why not? It is, in my opinion, a huge improvement and will provide the necessary information for readers in the USA and Canada (and other places using 120VAC grids).

The difference in efficiency from 110VAC to 230VAC is no more than 3 - 4%. From 110VAC to 120VAC it will be negligable but better. The mains frequency of 50Hz or 60Hz will have no effect on power supply performance.

If a power supply passes all tests at 110VAC (50Hz) then it will be a certain pass at 120VAC (60Hz) with very slight improvements in some areas.

Regards

Paul

I believe by US law, utilities are only required to maintain 10 or 15% tolerance (I can't remember which) from 120V, but most utilities do strive to maintain 5%.

121 to 123 volts here!

The outlet in my room nearest my multimeter gave me 126.6v with nothing plugged in. The A/C is off as well. Never noticed it was that high - barely at the +/-5% tolerance range of 114-126v that is allowed in the US. IIRC most countries using 230 allow 10% tolerances.

I will need to test it at varying times while the house is at different load levels to see its range.

Pc Perspective does the best PSU reviews I have ever seen online. Although not everone has access to variable autotransformers and dual tracing oscilloscopes, there's would be a nice format to at least check out if you were interested in PSU reviews and testing methodology.

The most recent reviews on OCC with the load tester make me all tingly inside though.

Here is mine:

Yes, they are getting better as well