Any qualified electrician will wire it to code in and out of the box. It is the same for audio applications as any other outlet. AFAIK ground loops are negated by properly grounding each line, at least that's what I've been told.
Dedicated Line Advise
I currently have a 20 amp dedicated line run to my small HiFi rig; amp, preamp, CDP, TT, power conditioning. I wish to add a second line using the same electrician who has worked on my house. It looks like he used 12 gauge Romex last time.
What are the key facts that I should know in case he is not familiar with doing wiring for audio systems?
I'm talking about the installation at the breaker box, e.g., keeping proper phase and preventing a ground-loop between the 2 circuits.
What are the key facts that I should know in case he is not familiar with doing wiring for audio systems?
I'm talking about the installation at the breaker box, e.g., keeping proper phase and preventing a ground-loop between the 2 circuits.
49 responses Add your response
When you say use the same phase, does that mean phase = leg. Use the same leg? I see that audio AC line 1 is installed on left side of circuit box, which is now full. As long as he puts line 2 on the right side of box, same phase, then everything is cool. Is that correct? Also, previous owner installed 220v furnace on left side and 220v dryer on right side. Am I in good shape for this install? Thanks. |
Definitely run both lines on the same phase/leg otherwise you will most surely get hum form your system. If you don't have enough room on one side, you can just move breaker's around. One of the best "upgrades" i did for my system was completely reconfiguring the electrical panel, tightening up all the connections etc. You can see a more detailed description on my systems page here on AG. Good Listening Peter |
Great info, many thanks. There is adaquate room on the right side of the box. Is this the best way to proceed... move line 1 to right side, add line 2 to right side (same phase). This would move the audio AC lines away from the furnace breaker on the left. Now there would also be room for additional lines. Your thoughts? |
BTW- It doesn’t matter which side of the breaker box a 220V breaker is mounted on. It’s still connected to both phases. Your Electrician will know what to do, regarding getting your audio breakers on the same phase. But- you might mention to him, you'd like the least number of appliances possible on that phase. |
Lowrider - if your panel is like mine (i.e. a two bank North American panel ) - the adjacent switches in each "bank" of switches (i.e. if you have multiple banks) alternate between the two phases - e.g. BANK "A" BANK "B" Switch # Phase Switch # Phase 1 A 15 B 2 B 16 A 3 A 17 B 4 B 18 A 5 A 19 B etc... For your two phase devices you will see a "linked switch PAIR" which takes two adjacent spots - one switch of the pair is connected to phase A and the other connected to phase B (or vice-versa) You need to make sure the electrician knows you require both lines on the same phase. He/she should understand how to connect to the same phase FYI - It only takes one two phase device to "pollute" both phases - so your goose is cooked - along with most other North American homes. The only real protection against noise introduced by two phase devices is to get 1. an Equitech transformer $$$. 2. a power re-generator I would not be too worried - unless the power in your area is prone to brown outs or surges, the noise from the furnace switch dissipates really quickly down the power-bus Which switch bank is immaterial, but the farther away from the two-phase device switches the better This link shows you a typical two-phase panel layout https://www.google.ca/search?q=two+phase+house+distribution+panel+pic&num=20&tbm=isch&tb... Regards... |
forgot to add, the most noise you will hear from two phase motors is when they turn off and on, normally via a solenoid relay. Any more than that and I would co sider having the motor replaced - it's past its prime. My furnace has a setting that runs the fan at a low speed all the time. so there is no switching as such and no high current spikes on the supply, which can cause a brief voltage drop, depending on your supply. regards |
willie, I appreciate your time. First, all electrical is modern and up to code. Second, I have a different circuit box, it's for a small row home and the layout is like this... BANK "A" BANK "B" Switch # Switch # 1 A 2 3 B 4 5 A 6 7 B 8 9 A 10 .... up to # 20 **I found a diagram of my box online and this is what was posted. ------------------------------------------------------- #1, 3 are a "linked switch PAIR" for furnace. #2, 4 are linked and marked as MAIN DISCONNECT. and BTW, the electrician placed my audio line in #5. Are you familiar with this type of box? |
Lowrider, I’ll just add to the many excellent comments that have been provided the suggestion that it may be worthwhile to re-read this thread from about two years ago. Note particularly the comments by electrician expert extraordinaire Jea48 (Jim). And in regard to ground loops, which you had asked about in your initial post above, note especially his reference to pages 31 through 37 of this paper. It is explained in those pages that what "drives 99% of all ground loops" (to a greater or lesser degree depending on the designs of the specific components that are involved -- my words) is lack of uniform geometry in the power wiring. Which in turn results in the magnetic fields surrounding the hot and neutral conductors, that would ideally cancel each other perfectly at the mid-point between the conductors due to the currents which produce those fields being in opposite directions, cancelling less than perfectly, and therefore causing voltages to be induced in the safety ground wire. Which in turn will result in ground loop issues to a degree that depends on how safety ground and signal ground are connected to each other within any pair of interconnected components. As you’ll see in the paper, the Romex you indicated is being used in the existing run is a good choice in that regard, given its essentially uniform geometry. Note also the list of common sources of high frequency noise, on page 37. Good luck. Best regards, -- Al |
Al, always appreciate when you participate. Thanks for reminding me of that thread. Early on in this hobby I only had one line installed since I had low power devices; live and learn. There's great info that you've provided me and have downloaded it. Through our conversations, you know about the atypical grounding design of my amp and I'm glad you alerted me to possible unpredictable results. (and I had a lengthy conversation with Jensen; thanks). But adding one or more dedicated lines is still the plan. |
Lowrider - The box you have is just another variant of a two phase supply. The electrician will simply use two switches and ensure they are on the same phase - e.g. switch positions 7 and 8 or 9 and 10 (assuming they are available.) It does not matter which phase they are located on, as long as they are both on the same phase. Some people believe having outlets on different phases do not improve SQ - HOWEVER, from a safety perspective, havin all components on a single phase is safer should one component fail, there is no risk of exposure to voltages across two different phases, which is much more dangerous Placing the new breakers at position 19 & 20 will ensure they are located as far as possible from the noisy appliance breakers. A separate breaker panel just for the audio circuits might be the quietest solution - but more expensive Regards... |
Your mixing phase and leg. There are one 2 legs split from one phase. Read some of these replys to the phase question, they are in layman terms. http://www.hobby-machinist.com/threads/why-is-220v-called-single-phase-when-it-has-two-phases.17428/ |
Lowrider, somehow I lost tract of your post and not responded. However seems you have gotten the info you requested, and more, from those that are far more knowledgable than I. Lots of great info here, thanks for the post. As pre willie, I have my audio lines at the bottom of my box and the dual phase breakers at the top. |
Lowrider - in your depiction of your panel - for two lines on the same phase.... You would have one switch on 19 and the other on 20 - which would be PHASE B Alternatively, you could have the switches placed at locations 17 and 18 - which would be on PHASE A Either option is OK - just keep these switches away from the two phase switch-pairs Regards... |
Lowrider - since you will be juggleing swtches - I believe the best place for the two phase switches will be closest to the end of the panel where the incoming wire connects to it - that way any noise will dissipate back to the supply The audio switches would be at the opposite end farthest away from the two phase switches. One other thing - ensure the electrician maintains the "power balance" between the two phases Regards... |
Not trying to start any argument here, but there is absolutely no reason for the equipment to be on the same phase at all. The AC is converted to DC within the device, so AC voltage phasing is irrelevant. As long as the dedicated line have hot, neutral and ground going back to the panel and do not share neutral or ground before the panel. you are fine. Also, any electrician worth their salt will want to have your AC panel loads balanced on both phases. I read that many posts about dedicated lines and some advocate placing them on the same phase. But, if your equipment carries a large load =, that load must be balanced on the AC panel to avoid overloads. I ran dedicated lines for my audio equipment. My house fortunately is on a raised foundation, so crawling underneath the house was the way to go. Hot, neutral and ground all back to the panel and not shared. I have to Audio Research REF 250 mono amps connected to the individual dedicated lines back to the panel (on the same phase at the panel) and one Mark Levinson 23.5 connected to the other phase via a dedicated line. My low level equipment are all connected to a Transparent Audio Power Isolator 8 line conditioner, then via a dedicated line back to the panel. I tried to balance the loads as best I could. Noise floor is just gone. No ground loops, no buzz, no noise whatsoever. no equipment's ground lifted via cheaters. Noticeable difference from when I didn't have dedicated lines. Being an Electrical Engineer, I know that AC is AC and DC is DC and every piece of equipment I use converts the AC to DC internally. Therefore, phase absolutely does not matter and my system's sound is wonderful. If you are going to put all your equipment on the same phase at the panel, try to make sure your house loads are balanced at the panel. enjoy |
It seems that my circuit box is balanced... Left Right - furnace, - refrigerator 15amp 30amp linked. - light duty 15a - A/C 20amp - dryer, 30amp, linked - light duty 15a But, the original electrician did a poor layout of the breakers for my purposes. The only open area for expansion is in the middle of the box. High current breakers are at the top and the bottom. |
Minorl - my only preference for keeping the gear on the same phase is for safety only. In the event of some very rare condition(s) occurring in audio components, having the components split between two phases could result in (and I stress very rare and could) - a voltage difference between present on the chassis of two components of 240 volts and not 120 volts if the components were on the same phase. e.g. I’ve read of members "removing the ground pin" in order to get rid of hum - this is one action that I believe can have dire consequences, since it defeats the purpose of the ground wide in that components - the chassis could become live if something inside fails. e.g. I’ve also experience third party power cables that were wired incorrectly, i.e. the live wire went to the neutral side of the IEC connector, which, from the perspective of AC makes no difference in operation - however from a safety perspective it could mean that the neutral side of the input to the power supply is live. Most of these issues may not impact general component operation, but there are design standards for a reason - safety! I also believe there are other factors pertaining to the age of the external supply lines and transformers that might result in noise being transferred to the components, but that may only occur when the electrical infrastructure is old - which does not apply in this case. Won't happen? - maybe not, but I've lost count of the number of musicians that have been electrocuted from what was supposed to be - safe amplification I also do not wish to start a debate - but I thought I would provide the above info for everyone’s consideration. BTW - I’m also in the EE camp :-) Cheers |
Minorl, Having worked on this issue extensively with many different systems, the chance of getting ground loop hum when powering equipment from the two opposing phases in your panel is greatly increased. While I agree that in theory it should not matter, in practice in most cases it does. You mention that your two amps are powered from the same leg in your panel while your front end is powered from the other leg, however you also mention that "My low level equipment are all connected to a Transparent Audio Power Isolator 8 line conditioner, then via a dedicated line back to the panel." This could be the one reason that you don't experience this phenomena, as an experiment why not try to eliminate this one and see (hear) what the result is. Coming from the EE camp also Good Listening Peter |
Having worked on this issue extensively with many different systems, the chance of getting ground loop hum when powering equipment from the two opposing phases in your panel is greatly increased. While I agree that in theory it should not matter, in practice in most cases it does.According to a reference authored by world renowned authorities on relevant aspects of electrical and electronic design, which was cited in this thread, it even matters in theory. See the first of my two posts in that thread dated 5-16-2013, which provides brief relevant excerpts of their paper, as well as my comments on it. The paper was initially cited and commented on in the thread by electrician extraordinaire Jea48 (Jim). The thread also contains further discussion of both this issue and the criticality (or lack thereof) of load balancing, by me, Minorl, Peter (pbnaudio), and Jim (Jea48) among others. It would seem that those on opposing sides of these issues will just have to agree to respectfully disagree. As for me, FWIW, I’m with Peter and Jim on these issues. Best regards, -- Al |
One thing that I like about Audiogon is that one can have good discussions with others here without having to worry about trolls and negative discord. I disagree with the idea that the power feed must come from the same leg on the power panel and we had discussions about that here and yes, we do agree to disagree. Having the power feed from the same leg will not be a problem at all, except as I mentioned the load at the panel may not be balanced. Which can cause electrical issues. I have seen nor heard any evidence that having power from both legs causes any problems at all and in my case it definitely does not. But, remember, that either way, one must not share ground or neutrals with anything. The hot, neutral and ground leads must go all the way back to the panel. Other things that can and often do cause ground loops and buzzing is poor interconnect cables where the return is tied to the shield. Or, if the electrical component has a poorly designed grounding scheme. There are many reasons why people experience ground loops/buzzing. The very last reason that I would suspect would be using separate power feeds from the panel. The ground and neutral are all tied together in the panel. So as long as these run independently back to the panel, you are good. I suspect bad component ground design scheme or bad/poor interconnects. In my case, this is a non-issue and I have my power feeds balanced on both sides of the panel. If someone has this same set up and has ground loop or noise problems, I would love to hear about it. Audiogon is a great place for these types of discussions. enjoy |
ptss, The cost of installing a dedicated 20amp line plus grounded outlet was $200 back in 2010. But now, it will be more complicated since I'll need to reconfigure the box; moving high-current appliances away from the audio lines. I don't know the hourly rate for labor to do that. And I'll be adding Porter Ports this time. |
lowrider57; moving hot leads from one phase to another in the panel takes no time at all for an electrician. Adding a new box takes a little more work. But what you described is really not complicated. You could actually do this yourself if you knew how. On my house it is simple. I would go outside to my meter panel. There is a large circuit breaker for my house. Yes it is that old. I will trip off that circuit breaker, de-energizing the house feed from the meter. (I actually don't have to do this, but it is safer), Then I would go into the house to the breaker panel in my house. I would locate the breaker that feeds the line described, then remove the breaker, take the lead from that breaker feed and move it to the other hot phase in the panel. reconnect the circuit breaker, turn on the main breaker and you are done. If you are doing this yourself, just take a volt meter with you and measure that the voltage is turned off before proceeding. There are two hot leads coming into your home. An A and B phase and a neutral. A is on one side of the panel and B is on the other. They both measure 120VAC with respect to the neutral. They are out of phase with each other. If you open your breaker panel, you will actually see the two phase wires connected to the breaker bus bars on either side. You will see the neutral also and a ground (which is your house ground). If you are not comfortable doing this, an electrician shouldn't charge more that an hour's labor (that is very conservative) to do this. enjoy |
Minorl, While I agree that it is quite easy to change a breaker to the other phase in a panel - but if one is not familiar at all with electrical work - I will strongly caution about the DIY approach on this one. For one there is lethal voltages inside the panel and even though the main beaker is turned off, depending on the design of the panel there could still be live voltage inside the panel - in my main panel the feed coming from the meter to the main breaker are still live with the breaker in its off position. Another one I will never forget, while an electrician apprentice back in Denmark, where I'm originally from, we were called to a vacation home to install an electrical outlet for a TV. Initially the owner had tried to install it himself, even though back there its actually again the law. Also every house is fed with three phases and neutral, 220V from neutral to each phase and 380V between the phases. He managed to get 380V on the outlet, and there was an empty TV stand in front of the outlet :-) Good Listening Peter |
Thanks for the detailed info, minor1. My box has the Main Disconnect linked on #2 and 4, so it's very convenient. I'm sure I could move a breaker myself, although each wire may only be cut to length. It's a very poor layout of my household appliances. Even though the load is balanced, there are some high-current breakers in the middle, then blanks and low current, then more appliances at the bottom). If it's only an hour labor charge, I'm fine with that. Thanks. |
Peter, I have a quick story about my respect for electricity. I'm not an EE or electrician, but I did hold a 2nd Class FCC license and worked as an audio engineer. On my first remote, we were going to tie-in the truck to the venue (an old theater), so I went with the Chief Engineer to the basement and located the circuit boxes. He handed me a heavy length of wood and said that if he started to get electrocuted, I was to knock his body away from the wiring. |
I bought a home for my kids to live in while going to college. Built in 1923, it had a new box installed, actually 2 boxes. One outside box that carried a mains breaker which fed a interior box for the home. Never seen this before. If wanting to work on the interior box with no fear, simply throw the breakers on the exterior. Wish I had used this system when I built my home in 2000. Now, if I wanted to restructure the breaker positions in my home box I would have the utility company remove the supply meter for the day. |
I love these stories. This is why it is always important to use a volt meter and check to see that the voltage is zero on the phases. In the utility industry, one always checks hot voltage first to see if the meter is working, then check the "de-energized" circuit to see if it is zero, then go back and check the hot voltage again. to make sure there is no fault with the meter. Also, as always, it is better to hire a licensed Electrician if one does not know how to do this. Safer is always better. enjoy |
mesch "One outside box that
carried a mains breaker which fed a interior box for the home. Never
seen this before. If wanting to work on the interior box with no fear,
simply throw the breakers on the exterior. Wish I had used this system
when I built my home in 2000. Now, if I wanted to restructure the
breaker positions in my home box I would have the utility company remove
the supply meter for the day." That shouldn't be necessary. It would suffice to throw the master breaker in your service panel. |
I like the idea Coli has... If your gear will run 220 volt, you will have a lot more power available, and honestly could convert the line you have now to 220 and use a regular plug near by to run the 120 volt stuff. Maybe even save a few $ as it would only take a different breaker. If you still want the second line I would make it 220 if you have any gear that can use it. |
@Lowrider57 If 120V is fine why do you want another line? I assume you need more power in this location by adding in another line VS just wanting another line to look at. I don't know your level of knowledge in regards to power, but if you double the Voltage 240V in this case the draw your equipment has in terms of amps will drop in half. So basically you can run twice the amount of draw in watts on the same wire you already have if you change the breaker in the box, and and plugs at the other end the cost from your electrician should be much much lower. I'm also assume the area already has an outlet near by so you have 120V available for the TV, cable box and the new 220 Line can take care of the hungry power hogs like the amps. Example of your power avalible now in 120 VS 240 setup Volts * Amps = wattage. 120 * 20 = 2400 Watts of power 240 * 20 = 4800 Watts of power. To be honest I'm setting up a new HT and I'm hoping I won't need to run more power for it but this thread made me think about it and Coli Idea was like hitting the bell at the county fair, If I have to run another line it will be 240 as it just makes more sense. But in your case if your equipment can use 240 it would be a big money saver. Also not talked about is you could in theory install a small breaker box and convert the new 240 line back to 2 120 volt lines. What my long winded TLDR point is there are possibly many more options available some potentially at less costs, and possibly better as well. |
@imjustdave, I appreciate your input. I'm adding an additional line so that the power amp can be isolated and have its own breaker. I am aware that if I doubled the voltage to 240V, the current draw from my system would be less. I just don't think it's necessary with my small system and small room. And to be honest, I'd like to keep the costs down, given that I will be asking the electrician to rearrange the breakers in the circuit box for optimal placement of the audio lines. As far as the cost of my electric bill, I don't remember noticing an increase after I added my high power amp which is powered up 24/7. It's SS and probably doesn't draw much current at idle. |
