[ctviggen]

I don't know if it's "dangerous" per se, but having a separate earth ground is a violation of code, UNLESS the second earth ground is connected to the main earth ground using #6 sized or larger wire. It would help, though, to define what is meant by a "ground".  The neutral (white) and ground (clear/no insulation) wires all run back to the electrical panel. They run to large metal pieces that are themselves connected to the earth ground.  The earth ground is typically a long copper rod pounded into the ground.  However, metal pipes of the house may at times be the earth ground.  There is a very large copper wire that connects the metal pieces in the panel to the earth ground.  Neutral (white, usually) is considered Neutral as it is attached to the earth ground.  Hot (black or red) is not attached to the earth ground.  Both neutral and hot contain one phase of 220v (therefore, each phase is 110v). 

If what JLM means is that his copper ground wires from his outlets get connected to a separate earth ground that is not connected to the house's earth ground, that's a violation of the NEC (and email me if you want a copy of the section, as I have a copy of the NEC).  It can also cause ground loops, which is a bad thing.  If it's something else, it might not be a violation of the NEC.  Is it "dangerous"?  It's unlikely that it's dangerous.  However, many of the rules in the NEC come about because of something that has happened.  For instance, it's code now to put the outlets in so that the ground is up.  This looks odd to me, but fires have been caused by a thin piece of metal falling and hitting the hot.  Having the ground up means that metal should hit ground.

[andyr]

Hi all,

I am planning on setting up a sub power-pannel in my audio room to provide 2 dedicated 20amp circuit to 1) amp and 2) preamp, SB3, EA-DAC1 + Projector (digital gear).

Any comment on this? 

Hi Oris,

I second Occam's comments that, whatever you do, you must make sure you satisfy your electrical code to avoid your insurance company being able to wiggle out of a claim.

Now budyog gave you a pretty straight "waste of time" comment in response to your idea of having 2 x 20 amp circuits.  Mind you, he also categorically said there was no way your amps could be drawing 500w at idle ... so maybe you need to take everything he says with a bucketful of salt?? 

I've been researching mains power recently as I am in the middle of major renovations to my house - so now is the time to make any changes.  The effect of AC power on your sound - like component run-in or the effect of different dielectrics - is something that people who are "engineers" (ie. they believe measurement is king) tend to dismiss.  In other words, they don't "believe" and think there's no point in experimenting.  However, other people do decide to experiment - not because they have "faith" that something will work but because they have an open mind that it might! 

Of course, having proved to themselves that it makes a difference, they generally proselytise and try to convert others (so they too will gain the benefit!) ... to be met with disdain from the "engineer" types! 

I personally am prepared to take on ideas which other people have found out work through their own experiments and so I'm going to implement the ideas of one, Roy K. Riches in the UK who has experimented with AC power - even so far as to install 6 different circuit-breaker boxes in his house (for 6 weeks each, to "run them in") and listen to how they made his system sound.  You should be able to find his posts on the "Pink Fish Media" Forum.

Roy recommends doing exactly what you say (ie. a dedicated circuit-breaker box , aka "Consumer Unit", for hifi) but he says the ideal is to have a separate circuit for EACH component!  And all circuits should be the same guage wire and be the same length (to minimise earth potential differences).

Moreover, 32 amp circuit breakers will typically sound better than 20 amp MCBs - so you should use 32 amp wiring, not just 20 amp.  And certainly never have power amps on the same circuit as source components nor have digital components (which typically have switched PSes) on the same circuit as components which have conventional PSes.

If you want to get even more anal, rearrange your Consumer Unit so that the hi-fi circuits (or the circuit which feeds your dedicated hi-fi CU) are/is nearest the input feed from the street.  And locate the circuits which have fridges, computers, TVs and dimmers furthest away from the feed, to minimise noise transmission into the hi-fi circuits.

Regards,

Andy

[warnerwh]

Bob: When did the NEC start to require receptacles to be installed with the ground up? Last I saw either way has been acceptable. I'm one that likes the ground on the bottom.

With the ground on bottom I figure that if a cord starts to fall out the last contact made will be the ground. If a piece of metal falls and shorts ground to hot or neutral to hot the breaker should trip, right?

I just rewired a good portion of my rental property and haven't had the final inspection yet and definitely don't want to have to redo every receptacle. Thanks

[oscar]

I had a party one time where I decided to hookup the extra refrigerator in the garage to keep some of the goodies cold. Turned out the circuit this extra compressor was using turned out to be the same circuit breaker my HT/stereo system was hooked up to. Half the house went dark when a particularly loud movie scene caused the breaker to pop. The circuit breaker was never the same at which point I decided to go to dedicated lines.

I overkilled with four (4) separate 20amp circuits which probably had created some ground loop problems.  At the time I had inefficient speakers and visions of future massive power-soak monoblock, inefficient SS amps to drive five channels. Certainly I had definite sound improvements going to dedicated lines but I'm sure I could have done better.  E.g separate ground poles, using the same phase etc.

[JLM]

josh/CT,

I'm not an electrican and barely made it through my one electrical engineering class 30 years ago, so I may be using the wrong terms.  I have a 2nd earth grounding rod with copper strap bolted to it for the audio circuits.  Everything else is wired with the rest of the house.

[oris98]

Well,

I am going to try to turn on all my equipment tonight to give it a try (worse case is the panal switch flipped) and see if the std 15amp circuit can tolerate the load especially with a action movie.  If it works ok, I may just get one 20amp circuit instead.   
Will update you guys later !