Measurements for a dedicated line
The question of whether a homeowner should get a dedicated line is often like "should I get bangs." It’s a little complicated. Here are a couple of reasons to consider not:
I. My experience is that you won’t eliminate all the other noise coming from your home even if you do run a dedicated line. I still hear motors switching on and off despite being on completely different circuits.
II. A little resistance and a little inductance may actually be a good thing in keeping noise out of your line, so overkill on the wire gauge may not help this.
Why you definitely should get a dedicated line, with thicker wiring:
Less voltage sag.
Voltage sag means that under load the resistance in the line will cause the AC cabling int he wall itself to consume some of the AC voltage, giving your gear less volts to work with. This sag is proportional to current, so the more amps your gear is drawing the more sag.
This sag is something you can measure. There are two things you need to look: The hot to neutral voltage and the neutral to ground.
With nothing on the circuit your N-E (neutral to earth or ground) should be 2V or less. If it’s significantly higher than that stop and call an electrician. That’s true for any circuit in your home. High N-E values are indicators of a problem which may be in the circuit or in the service wiring from outside to the panel.
What happens when you turn your equipment on and play music is that the line will sag. The H-N (hot to neutral) voltage will drop, and the N-E will go up. Some sag as you turn on big amps is normal. So long as you are not tripping breakers you are fine. What you want to measure is the sag after your system has stabilized and while it’s playing music.
Keep an eye on the N-E value, as this will be a good indicator of the sag independent of the incoming line voltage. It may also point out where you may have issues. That is, if you measure an extra 2V of N-E, your sag is probably around 4V, so you went from 120V to 116V and you can be relatively comfortable it isn’t outside influences.
Of course, any good multimeter will work for this but I like plug in meters with built in N-E measurements. This one is cheap, and the N-E may not be hyper accurate, but it is the only device I’ve found on Amazon that will show you both the H-N and N-E voltages at the same time.
The nice thing about any plug-in type voltage meter is you can watch it over a couple of days without hand holding probes in the socket.
If you find another which does both please post.
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. |
@tomic601 Several of my motors are 220V.
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The neutral should have no more than 2 volts to ground. If you have more than that (as measured at the receptacle) the first thing to do is to go to all the outlets with a plug in receptacle tester and make sure they all read ’wired correctly’ and none read 'open ground', in which case call an electrician. If the receptacles are okay, go to the panel and check to see if there is the same voltage between the neutral and ground bus or neutral and panel bond. If it is the same then that is pretty much the resistance to ground causing the neutral voltage. Check the panel bonds to both the panel and the ground rod. If the voltage between G-N buss bars is a lot less than measured at the receptacles, then the most likely culprit is a loose connection somewhere in the circuit. First tighten all the lugs on the neutral and ground bars (a lot of times this will fix it). If that doesn’t do it then you have to trace the circuit for j-boxes and check or replace the wire nuts, then work your way to each receptacle and check the pigtails. If you have the backstab connectors, those too are a source of resistance. Somewhere along the line a loose connection places a high impedance on the neutral creating a voltage divider, which shows as a few volts on the neutral. |
I have a dedicated line and hear no such noise or interference from other circuits, motors etc it also was not expensive or that difficult. I also did not go nuts, no need to. Simple 12 awg romex 50ft, 20 amp breaker, AQ nrg Edison receptacle. Sounds great, no noise that I can hear, and provides enough power to my class A sugden and all the rest. Did it myself to boot. |
@audioguy85 I did exactly the same thing, only my main floor run was 30 feet, and my basement system was 20 feet. I use a Cardas Audio 4181 receptacles. Same result Zero noise, larger soundstage, and more definition. |
