electrical phase

I am reading 241 Volts phase to phase with a Fluke 2860 A. Phase to ground is 120 on each leg.

On the topic of this thread. Would audiophiles not benefit from my suggestion of keeping one of the two 120 volt supplies as the primary power for the stereo and the noisy stuff on the other?

Other than the confusion about the set up of the breakers in the box and the fact that I have 3 phase, it seems the two 120 volt supplies most readers (probably) have could still benefit from Killerpiglets idea of separate runs.

Also, why could everyone not use a meter to differentiate between the two 120 volt drops? I do this often behind my equipment. I just meter several plugs, and the one that is the low leg gets the digital equipment, as I keep it on the opposite run from the analog gear.

I would be surprised if two runs coming in were EXACTLY the same voltage, and this would be an easy way to tell them apart. It always works here, the voltage may change a little during peak usage periods, but the two supplies stay almost the exact number of volts apart, day or night.

Electrical comes into most homes in the US at 240 volt, phase one and phase two.

This means phase one @ 120 Volts and phase two at 120 Volts. These together such as to a clothes dryer or electric oven is how you arrive at 240 Volts.

If problematic household products are on the phase OTHER than the one your audio gear is on, the stereo is isolated from the pollution introduced by these products. The worst of these are refrigerators, microwave ovens and household computers, although any electric motor or pump is likely to cause noise on the line.

If you look at your electrical panel, there are twin rows of breakers or fuses ( usually running vertically top to bottom ). One vertical row is first phase 120 Volt supply and the other vertical row is the second 120 Volt supply.

Basically if all the stereo gear is connected to breakers or fuses on the same side of the panel, they are more isolated than if they share power with the household products that generate noise.

During new construction or a complete replacement of a panel, have your electrician read each of the two supplies with a VOM. Most of the time they are different.

In my neighborhood, readings are usually around 119.5 for one, and 121.7 for the other. I chose the 121.7 to dedicate to audio.

I have the rare luck to have a three phase drop, and dedicate that to the air conditioning system. This further isolates noise from the audio system and saves power.

Glen, I have three phase as pointed out in my post, it is 120 / 240 as I mentioned already.

My comments are correct for my particular configuration and did explain that there are two supplies coming into my home. Are you saying that in most home electrical drops the panel does not get power from two different 120 volt supplies?

I have two panels in my utility drop closet. One three phase that runs the AC and one that does not contain the third leg, that has two 120 volt AC drops.

Inside the house is three panels, two are 100 amp Square D and both have two different voltages supplying them (they always meter differently).

The third panel is 220 only, and the two hot legs measure the same as each of the 120 Volt supplies.

The power coming in is a four line double zero cable, and a 750 amp box with a amprobe type meter (pull the meter, the power stays on).

I am reading the two phases that come into the house, the third phase as mentioned already, goes to the big commercial AC unit that keeps us comfortable during the hot Texas summers.

Glen, regarding your comment: There's no way to separate a 2-pole 220v breaker to one side or the other. I think we all know that? No matter what you do the noise from your 220 circuits will always be present on either side of the panel.

Looks like from what you said that the 220 shares with both circuits, but the two 120 Volt drops ARE separate, and therefore could be dedicated specifically to the stereo for one drop and noisy ( refrigerator, computers, etc.) on the other.

Back again to the fact that they can be separated, and that is what I prefer to do. Your suggestion to balance the panel is your answer to best sound. So until someone has a bunch of time on their hands to try this both ways (would that prove anything owing to the differences home to home?) we are still two opinions.