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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.
128x128lowrider57
williewonka
3,075 posts
 
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
pbnaudio's avatar
pbnaudio
1,613 posts
 
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
almarg's avatar
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almarg
9,670 posts
 
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

minorl
1,015 posts
 

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
1,964 posts
 
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