@dpop - A GFCI outlet senses differences in current at the outlet between the hot and neutral. A voltage on the ground won’t cause this, necessarily. A leak between neutral and ground at the appliance connected would.
In fact, GFCI outlets don’t even need a working ground, so can be used to retrofit outlets without a ground conductor. If all is well, the current flowing from hot and through the neutral back to the panel should be identical.
The theory of voltage differences between neutral and ground is related to whether or not current is flowing. Since ground should have no current, it should also have the same voltage as at the panel. Neutral on the other hand, when it has current flowing through it, will be lifted from ground by the imperfect resistance of the copper wire.
Ohms Law:
Volts = A * R
So with 1 Amp, and a resistance of 0.1 Ohms you should see Neutral lift to 0.1V above ground.
The ground conductor also follows the same math, but:
Volts = 0 Amps * 5 R = 0 Volts
That is, from one end of the ground to the other is still 0 Volts.
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The voltage drop / 2 method only works if the voltage drop is equal. It is possible the voltage drop is higher on the hot due to resistance.
Best to measure with a multimeter for the most accurate results.
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So, A'gon apparently got upset with me that I said A M A Z O N in an e-mail. Sheesh! :D
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Unfortunately, it's a random draw with this one. Mine was within 1-2 volts. Others have reported as the poster in the thread did, that some can be much more off than that. Good news is [filtered] allows free returns. They do make other meters which get better ratings on reliability, but I dont' know of any that include the Neutral to Earth measurement standard.
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AC voltage, harmonic distortion and line frequency are all measurable
Indeed, but most of us can only measure AC voltage. Harmonic distortion is definitely not something you get with your average multimeter, and the one thing I have the most faith in is the AC frequency. So in the absence of anything else, it would be nice to correlate AC voltage with listening experience.
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@bolong No, not at all. I'm just kind of curious why. :)
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@bolong It would be nice if you got a plug - in V meter and could look at it during the day and night to see if you have better voltage at night. I'd be really curious.
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@bolong I'd be interested in knowing if that's a voltage or noise issue.
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@dpop The specs seem nice. One of the major issues with WHSP units is the high clamping voltage. The other is activation time. Another is the ability for a surge current to be induced by the AC wiring in the house.
For all these reasons, I still protect anything sensitive and/or expensive with a Furman or Tripp Lite at the outlets.
Still, I have sunk a lot of money into the advanced breakers, home automation, GFCI outlets and fire alarms in this house, so the WHSP unit in my panel is very worthwhile.
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@dpop Sounds good!!
GFCI outlets are cheaper ($20), but if it's not in a convenient location to reset when it trips then a new combination breaker is the way to go.
I also have Siemens. My panel used 100% Siemens breakers, that were 15 years old when I moved in. My neighbor had a weird assortment of breaker brands in hers. I've replaced 100% of the single pole breakers and added a whole-house surge suppressor. It makes me feel better, but I still lost a laptop in a storm that had no other surge protector on it.
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My house was built in 1942, and the pizza oven wiring has never been updated, except with a new outlet at some point.
@dpop
Ahhh! Yeah, you can’t do that today. The microwave gets it’s own circuit, which as of 2023 has to be CAFCI and GFCI protected.
Within the past 10 years I updated that microwave/pizza oven circuit breaker to the recent AFCI type.
Nice! Please make sure that all your kitchen counter top circuits are GFCI protected as well. Not sure if an outlet or updated breaker will be the most convenient for you in this case. Leave the fridge alone though, those trip GFCIs all the time. GFCI for kitchen counter top outlets has been code for decades but the latest 2023 NEC code expands GFCI to the dishwasher, microwave, and washer/dryer combos. I’m not sure you need to go that crazy, but I do think it’s worth the GFCI outlets on the counter tops for sure, and any outlets under a kitchen counter as well.
If you buy more GFCI outlets, any major brand but Leviton seem to have high trust factors with online electricians.
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@dpop Excellent investigations!! :) While I applaud your work, should also point out how few amps you are drawing is contributing to the stability of the voltage. Your wiring could handle 30 Amps, and you are drawing 2 at peak usage.
Audiophiles should evaluate the potential benefits vs. costs. The longer the circuit from the main panel, the more the power draw is, the more worthwhile a dedicated, large gauge circuit becomes.
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@dpop Those are certainly popular, and I believe the original. There are now dozens of watt / voltage meters out there, with a variety of smart features, including wifi connectivity. What I've yet to find is one that measures N-E at the same time as the V. Still, being able to chart your V over a week can really help you understand your power issues.
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Just so readers understand, when a circuit has no load on it you are looking at the best case scenario. Running a dedicated line won't get you better than that.
Where a dedicated line improves things is in the case of a circuit with load. Less load + thicker cables should reduce voltage sag.
Point is, you can't do better than the panel voltage, and if it's going up and down, your dedicated circuit won't magically improve upon that.
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@baylinor You have really good house power! I have a quasi-dedicated circuit. It runs the HT and a USB house camera on it. I still have more fluctuations in voltage than that, even with nothing on. Typical voltages, with an unused circuit (except USB camera) runs 115-123V and my heat pumps and air handlers definitely move that needle as do the seasons. BTW, I live in an area served by pad mounted transformers and underground feeds, so it should be relatively stable compared to pole mounted power.
I use a Furman voltage regulator as the "front-end" to my power conditioners to ensure the power is even tighter even when running the full system.
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If you are doing a dedicated line, there's a couple of interesting alternatives. Getting a sub panel, and running 240V instead of 120V.
A sub panel means you run say 6 gauge wiring up to your listening room and then use short 12 gauge runs to each outlet. Since you have 6 gauge wiring, your overall voltage sag is going to be negligible.
Another alternative is to run 240V and use a balanced power conditioner to step it down. Again, you cut the current in half, therefore the sag is halved.
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@carlsbad2 Honestly haven't kept up with them that closely. I remember there was an original generation that was essentially using linear amplifiers, then they switched to Class D.
At the same time the founder of Jensen Transformers (really nice guy) founded another power conditioning company, Perfect Power? Forgot the exact name, that used buck/boost transformers. Very efficient compared to the PP, but still based on a linear amp. Sadly that didn't really go anywhere. Sounded like an excellent compromise IMHO.
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@carlsbad2 - The one thing about the Class D power plants is that they do in fact output quite a bit of noise. Personally I prefer to use an old-school voltage regulator.
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@dpop The N-E measurement is the same as the H-N, just volts. You can do the same with any multimeter. The ground wire normally has zero current, and remains at 0 V. The neutral though carries the same current as the hot. It’s that current that creates an elevated voltage. Consider:
V = A * R
So, on a lightly loaded circuit, with 1 Ohm, the neutral will be:
V = 5A x 1 Ohm = 5V.
The trick here is that the Hot will suffer the same voltage drop, 5V. So while the panel may be 120V, you have dropped 5V on the hot and 5 at the neutral so your wall socket will be 110 V just from voltage sag.
OK, this is starting to make a little more sense now. A device on the circuit being tested has to be consuming *some* current for the N - E figure to take place or appear. Got it.
The neutral wire has to have current to elevate the voltage above zero, yes, but you can still measure the voltage even if the voltage is zerol
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Let me rephrase, assuming your circuit has 0 amps, N-E voltage should be the same as at your panel, because 0 current = 0 volts dropped across your circuit.
So to be thorough, make sure your starting point is good. if it isn't, you need an electrician right away.
Next, once current is flowing through your circuit an excessively high N-E indicates excess resistance on the neutral.
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@dpopov2272 Usually the cause is a bad connection upstream from you on the neutral circuit. Of course, having long runs/thin gauges contribute, but if yo find this number much higher it’s usually a bad upstream connection.
This can also happen if the neutral at the service panel is bad.
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