How to measure voltage at my outlet

carusoracer · « **on:** 9 Mar 2007, 03:24 pm »

I'm looking for the best way to measure the line voltage at my outlet in my living room

I'm no EE so the simplification is needed to explain. The Amplifier maker is requesting this number to complete the build. I'm in the US.

FWIW, I'm not sure of the reasoning as it should be built for standard 120 in case I move or demo anywhere etc I would think?

Any help appreciated

JoshK · « **Reply #1 on:** 9 Mar 2007, 03:37 pm »

Do you have a voltmeter or multimeter? If so you can *carefully* stick the leads into the wall socket to measure the voltage. In the US it should be between 115V-125V. In NYC area we tend to get >120.

Bob in St. Louis · « **Reply #2 on:** 9 Mar 2007, 03:43 pm »

Get yourself a volt meter. I've seen the cheap little plastic analog ones for less than $15 at places like Walmart, RatShack. (make sure it's able to read AC voltage)
The actual nomenclature varies from meter to meter, but turn the knob on the meter to one of these settings;
"ACV" (AC voltage)
"V~" (or "~V")
Stick the red probe into the outlet, stick the black probe in the outlet (not the ground hole).
DO NOT TOUCH THE METAL PROBE (Sorry, I don't know your level of intelligence)
The measurement you get will vary on the time of day (your neighbor may have a 1,000,000 BTU space heater) and whether things in your house are turned on like the furnace/air conditioner, water heater etc....
You might want to give him a voltage range. ie...get a voltage reading while everything in the house is off. Then another while all the electron sucking devises are cranked at full speed.

Bob

EDIT: Sorry Josh, I was typing while you were posting.

carusoracer · « **Reply #3 on:** 9 Mar 2007, 04:30 pm »

Thanks for the replies. Just did not know if anything else was required. Still not sure why my particular voltage was needed

honesthoff · « **Reply #4 on:** 9 Mar 2007, 06:30 pm »

If your ordering Odyssey it's because Klaus biases the amp to each owner. I had to do the same thing when I ordered mine. I took three readings (three different results) and averaged them.

ctviggen · « **Reply #5 on:** 9 Mar 2007, 06:45 pm »

My voltage varies too much for that. I'll see as low as 105 volts in the summer, and near 130 volts in the winter. (I have a Monster power center that has voltage on it, and you can't turn off the voltage reading.)

Bob in St. Louis · « **Reply #6 on:** 9 Mar 2007, 08:42 pm »

Quote from: ctviggen on 9 Mar 2007, 06:45 pm

I'll see as low as 105 volts in the summer, and near 130 volts in the winter.

I'll bet your PC, TV etc.. LOVES that! WOW!

Bob

ctviggen · « **Reply #7 on:** 9 Mar 2007, 08:45 pm »

I turn off the system (one breaker) and the computer for the low voltage. Higher voltage doesn't seem to hurt (at least not that I can decipher).

carusoracer · « **Reply #8 on:** 10 Mar 2007, 03:19 am »

FWIW, my reading is 123-125

Bill Baker · « **Reply #9 on:** 10 Mar 2007, 03:30 am »

It would be interesting to see what others around the country get as an average. Super high voltage could explain issues with some equipment? I have seen problems with certain Chinese tube products when running with excessive high voltages.

I see an average of 117 - 120 in my shop and at the benches. I wil have to do another reading this summer when the central air is running in every building in the neighborhood.

Audiovista · « **Reply #10 on:** 10 Mar 2007, 02:02 pm »

I live in NYC - Queens. During winter voltage is 117-120V, but in summer it drops, believe it or not, to 93V!!! Yes, I called ConEd (local utility) to complain, as this is well below NEMA standards (120V +10%, -15%, or 102-132V if I'm not mistaken), but they didn't take me seriously....Thinking of it, ConEd has two options - reduce voltage and power consumption or keep the voltage stiff and risk power outages. In my area, for the last 11 years there was only one power outage (August 2003), so I shouldn't complain.

Whoever is making your amp should make sure that it works at 105V and must not blow at 132V.

Boris

SET Man · « **Reply #11 on:** 10 Mar 2007, 06:31 pm »

Quote from: Audiovista on 10 Mar 2007, 02:02 pm

I live in NYC - Queens. During winter voltage is 117-120V, but in summer it drops, believe it or not, to 93V!!! Yes, I called ConEd (local utility) to complain, as this is well below NEMA standards (120V +10%, -15%, or 102-132V if I'm not mistaken), but they didn't take me seriously....Thinking of it, ConEd has two options - reduce voltage and power consumption or keep the voltage stiff and risk power outages. In my area, for the last 11 years there was only one power outage (August 2003), so I shouldn't complain.

Whoever is making your amp should make sure that it works at 105V and must not blow at 132V.

Boris

Hey!

I also live in Queens, NY.

Anyway, I remember when I used to live in Midtown Manhattan couple years ago in a 20 stories building and the voltage was around 126V and swing up an down around 120 to 127V often

But I must say that I'm pretty lucky that my current apartment... a small townhouse building here in Queens voltage is pretty steady at around 122V and range around 119V to 125V... not bad

Of cause it is another story in hot Summer time... that when the voltage drop a bit more and swing up and down more than in Winter

I was very worry about spike last Summer when it was very hot for couple of days.... but I was lucky that the electric did not went out in my neighborhood.

Anyway, for solid state this shouldn't be much of a problem up from 110 to 130V But for tube owner this is not good at the higher voltage

Boris, I think that voltage swing also have to do with the condition of the building that you live in also and I don't think ConEd people give a damn about this even if it is their false. And guess what? They have plan to increase the price of the eletricity in a few months from now.... right in time for Summer.

Take care,
Buddy

Audiovista · « **Reply #12 on:** 10 Mar 2007, 06:56 pm »

Buddy,

You're right that wiring in a building plays a role, but distance from a distribution transformer makes a lot bigger difference (if not, then wiring is in serious condition and a fire risk

). And, as I said, utilities regulate load by changing voltage to prevent outages. We have to live with that and ensure that our equipment survives normal voltage fluctuations.

Enjoy,
Boris

mjosef · « **Reply #13 on:** 10 Mar 2007, 07:26 pm »

Or buy a good voltage conditioner/stabilizer.

Wayne1 · « **Reply #14 on:** 10 Mar 2007, 08:33 pm »

Here is a neat little device I picked up for voltage and current monitoring:

The Kill-A-Watt Electric Usage Monitor.

Not only will it show you voltage, it will monitor current, frequency and power factor.

Here is a nice article about it

http://www.the-gadgeteer.com/review/kill_a_watt_electric_usage_monitor_review

You can find these things around the net for $25.00 or less.

ctviggen · « **Reply #15 on:** 10 Mar 2007, 09:17 pm »

That is cool. I'd like to get two of those, for each of what I assume to be some of the large draw devices, a mini-fridge and a freezer. I think, but I'm not sure, that the mini-fridge is a power hog.

JoshK · « **Reply #16 on:** 11 Mar 2007, 01:13 am »

Mine is about 124V according to my meter. This thread reminded me I wanted to add the meters to my power conditioner. Just got done... The ammeter isn't hooked up yet because I think it needs a shunt. It didn't say anything about needing a shunt but when I plugged in my drill press and turned it on, the meter went to >80A (maxed out). I have a 15a breaker in the back so that isn't possible.

JoshK · « **Reply #17 on:** 11 Mar 2007, 02:19 am »

Can anyone decipher what "f.s. = 5 amps use with ext. C.T.R. 80/5" means?

I am going to guess it means that Full Scale is 5 amps and that you need to use a shunt (80/5?) to make the ammeter scale to the meter scaling (up to 80a).

Audiovista · « **Reply #18 on:** 11 Mar 2007, 02:29 am »

I have the Kill-A-Watt and there is one thing I wanted to do, but never got a chance: check the power factor measurement against a calibrated instrument. There are different methods to calculate PF, based on current harmonics or V-I phase shift. In our world, the first method is useful. Luckilly, I have an access to good instruments and may do the test sometime next week.

Boris

ctviggen · « **Reply #19 on:** 11 Mar 2007, 04:03 pm »

Hey Josh,

I searched for that and had a hard time finding it. CTR might mean "Current Transformer Ratio". Maybe the 80 means 80mA should go through the ammeter? Then you determine the shunt resistance via this:

http://www.allaboutcircuits.com/vol_1/chpt_8/4.html

?

Can't quite figure this one out.