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Circuit Breaker to Outlet AC Wiring and Ground


Johnseye

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I would have the electrician run a heavy 120V feeder (say 40 to 60 Amp) to the music room. With a small 6 breaker box in/near the room.

That way everything can be connected to the same Safety Ground in that box.

 

Let the electrician worry about the connection to Planet Earth. It's called the GEC (Grounding Electrode Conductor). What you have now is probably all you need.

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I was writing about 40 to 60 Amps for a 120V circuit or 20 to 30 Amps for a 240V circuit.

 

One of the main reasons for the breaker box in the room is so that you only need one heavy Safety Ground/Protective Earth back to the main panel.

The shorter the S.G.s are from hi-fi component to component the better.

Nothing wrong with plastic conduit or real Romex® for that matter.

And if you use plastic conduit or  Romex®, you don't need Isolated Ground receptacles.

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1 hour ago, Johnseye said:

A couple other thoughts were: put power amps on their own circuit and separate heavy duty motors and compressors on a different phase from the audio equipment.

Actually it would be a different leg or pole as US residential power is center tapped single phase.

Anyway, yes it's a good idea to put separate heavy duty motors and compressors on a different leg from the audio equipment.

But smaller power amps should be on the same circuit as the rest of the audio equipment.

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1 hour ago, Johnseye said:

I was reading an article which stated the wiring should be "One with hot on one side of neutral.  The other on the other."  I don't know what this means exactly and it 2 electricians couldn't make sense of it.

Maybe it had something to do with that leg/pole thing. On leg is on one side of Neutral and  the other leg is on the other side.

So it's 240V from one Hot to the other.

On ther other hand it could mean something else.

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4 minutes ago, KingRex said:

I'm an electrician and have done a lot of experimenting on the best way to get power from my panel to my rack.  It's easy to create a ground Loop, but it's also very easy to avoid. Grounding is a very key element in the equation. An old ground rod attached to your panel may not drain as effectively as you want it to.  Utilizing dielectric potting material or a ufer ground in your foundation will greatly reduce unwanted noise.  

While the Safety Ground connection to the Neutral is an important part of the AC power system, the connection to Planet Earth does not enter into the day-to-day operation equation. It's only there for safety during thunderstorms, high voltage failures and to keep the Neutral near the potential of the soil.

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On 1/1/2018 at 7:01 PM, KingRex said:

What they are saying is use the same phase.  Always A or B phase.  There can be small differences in voltage between A and B phase.  That small voltage difference can cause voltage differential to ride on the ground casing humming.  

Small difference? Nope, there is a 240 Volt difference between the A and B leg or pole. It's a center tapped single phase system.

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On 1/1/2018 at 6:20 PM, Speedskater said:

While the Safety Ground connection to the Neutral is an important part of the AC power system, the connection to Planet Earth does not enter into the day-to-day operation equation. It's only there for safety during thunderstorms, high voltage failures and to keep the Neutral near the potential of the soil.

 

On 1/1/2018 at 7:03 PM, KingRex said:

True but untrue.  It matters and will affect the SQ of your system.

If the connection to Planet Earth changes the Sound Quality of your system, then something is wrong with the AC power wiring.

Maybe a lost Neutral or a Neutral, Safety Ground swap problem.

 

 

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As for Arc Fault Circuit Interrupters or Ground Fault Circuit Interrupters, more and more jurisdictions are requiring them in more circuits.

So with any new work or updates, they may be required. Now GFCI's are rather benign, but AFCI's can be problematic with legacy equipment or appliances. Oh wait, some power conditioners or surge suppressors can leak enough noise current onto the Safety Ground to trip a GFCI.

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2 minutes ago, Johnseye said:

I'm thinking about using this wire for the breaker to outlet run.  10awg twisted hot, neutral and ground.

Just twist the Hot and Neutral with the Safety Ground in close proximity. Bill Whitlock wrote a paper about this. With maybe 3 or 4 or 5 twists per foot (the number of twists is no big deal, just whatever is easy and looks good).  Most electricians will think that you are crazy. 

* * * * * * * * * *

For other readers doing 120V system wiring.

The Hot, Neutral and Safety Ground should have a 1 to 1 to 1 ratio. All in close proximity to each other (close as in the same conduit or box). This means that the job should use about the same lengths of Hot, Neutral and Safety Ground wire. If the Hot/Neutral split two directions in a junction box, then that's where the Safety Ground should split also.

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19 minutes ago, monteverdi said:

In that link I quoted one of the recommendations is to use 240V for amps etc..I am not likely to try that.

Very few of us have amps that are correctly setup for US style 240V. But it can be a good way to go. Also it's good to wire big permanently  installed isolation or balanced transformers with a 240V input and a 120V output or two 120V outputs.

 

Another thing, for huge home theater systems  with thousands of watts and 120V amplifiers (with balanced inputs). A 120/120V Multi-Wire Branch Circuit that uses both 120V power poles is a good idea.

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6 hours ago, Superdad said:

This will sound crazy, but twist to the left (which is actually called a right-hand lay).

I could see mechanical reasons for twisting stranded conductors one way rather than the other. But with solid wires, it doesn't matter.

 

6 hours ago, Superdad said:

Make sure your electrician uses the screw terminals of the outlets--not the quick push-in holes!

Yes those back-stab connections are bad news.  However there are some very good receptacles that at first glance look like back-stab. The wire goes thru a hole on the back, but is secured with a screw on the side.

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3 hours ago, KingRex said:

I have not re-read the article but I have never seen a high leg in a residential setting.  They only exist off Delta 3 phase transformers. Houses are 2 leg single phase.  Unless you have a serious growler mansion as well as 3 phase being available on the street and you request the utility provide it you wont see it.   I doubt it was a high leg unless he was powering a recording studio or a store showroom. 

Maybe 'pole' was a poor word choice. Because I agree with you.

 

As for High Leg Delta (or Red Dog Delta) no you wont see that in a home, but in an older apartment you could.

(most others will probably wonder what we are talking about)

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15 hours ago, Johnseye said:

Why can't I use 10-2 NMB?  Shouldn't I be able to use this NMB provided it's dedicated per circuit?

I really love Menards, but the nearest is a 2 hour drive. As to NM-B cable, I would go to a electrical supply store and get real SouthWire Romex®.  It's symmetrical enough, so that there is little to gain by going to a Twist Pair & ground. Not all the other NM-B cables are made so that they remain symmetrical after install.

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While SouthWire brand Romex® is excellent, Cryogenically  treating it is stupid!

If Romex® isn't printed on the cable and SouthWire isn't printed on the box, then it's not Romex, it's just ordinary NM-B (or C or UF).

If you need two circuits (and most systems don't)(and one's with a small 1000VA transformer sure don't) but for others doing big power:

Have the electrician run a feeder from the main breaker box to in/near the music room to a small breaker box and split the circuits there.

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10 minutes ago, Johnseye said:

How would you determine how many circuits to use?

Well you could add up all the component's nameplate values, or you could measure it with a 'Kill-a-Watt' meter.

But for a 1000VA transformer, one 15 Amp circuit is the limit. Actually the transformer limit is 8 Amps, but 15 Amp circuits are as small as we go.

 

Now for a 5000VA transformer, I'd go with two 20 Amp circuits.

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12 minutes ago, KingRex said:

They hum, away in another room. Remember, they have about a 7 percent loss. A 2.4 kva transfer wastes 168 Watts an hour.  X 24 a day x 30 days x 12 cents an hour adds up. 

While a transformer while waste some power even when idling, in an audio environment it won't approach rated power more than 1% of the time, if that.

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1 minute ago, Johnseye said:

 

 

@Speedskater, gmgraves points out why I was putting in two separate circuits.  I also explained this in my first post.  My 2 channel equipment is different from the HT equipment (amps, prepro, projector, etc.).  The idea is to keep them on separate breakers, but I was hoping to take advantage of the transformer for both.  Your suggestion of a feeder could get that done.

Tell me again, what size is your transformer?

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