[audiogoober]

I recently had a local certified electrician install a new SqaureD circuit panel. I spoke with one audio distributor who told me that with two vertical columns of breakers, all my dedicated stereo lines needed to be in the same vertical column (either left or right) to be on the same phase.

When my electrician was here doing the work, I told him this and he disagreed and said this was incorrect with this particular circuit panel. He tried to explain this to me but honestly lost me with his electrician lingo and choice of technical words.

Can anyone out there please confirm if my three dedicated stereo lines are wired correctly and all on the same phase? The three stereo circuits in question are # 27, 28 and 31. Photos of the panel configuration, and SqareD model/information are attached for your review.

Thanks in advance.

[JerryM]

Circuit #28 is not on the same phase as the other two circuits.

[Elizabeth]

Skip the theory. Go directly to experiment:
The way to tell is:
Each outlet has a hot, neutral, and ground.
If you stick a voltmeter (suitable for Ac240 volts) into the hot and neutal you get 120 volts. Ditti the hot and ground, you get 120 volts.
If you have another line, that duplex will be the same within itself.
In they both are on the same 'leg' then connecting the two hots (using the voltmeter will give you zero volts.
If they are NOT on the same leg, then that action of using the two hots will get you 240 volts.
Ditto a third. so if you cross connect all three separate HOT runs and get zero volts from trying two hots each. AB BC AC.. then you are 100% absolute on one leg.
If any combo gets you 240 volts. you are using two legs..

That 240 volt potential IS the issue with using more than one leg of incoming power.

Added: If as JerryM suggests the circuit #28 in not on the same phase as the other two.. then that hot connected to eiither of the other two hot wires is a potential of 240 volts.

[audiogoober]

Circuit #28 is not on the same phase as the other two circuits.

And how do I prove this to my electrician and make him return to fix the work?

[Wayner]

There is no "phase differential" in home wiring. You have 2 incoming 120 volt lines, a neutral, and a ground that goes to a copper rod pounded into the ground, outside of your home. The 2 120 volt lines are in the same "phase" and when you put the two 120 volt lines (instead of 1 120 volt line and a neutral), you have 240 volt. It is all single phase. Just because there are 2 120 circuits, does not mean you have 2 phases. This is a common misconception.

And Elizabeth is correct, to get 240 volt you need 120 volt from each of the 2 incoming branch circuits.

Wayner

[audiogoober]

There is no "phase differential" in home wiring. You have 2 incoming 120 volt lines a neutral and a ground that goes to a copper rod, pounded into the ground, outside of your home. The 2 120 volt lines are in the same "phase" and when you put the two 120 volt lines (instead of 1 120 volt line and a neutral), you have 240 volt. It is all single phase.

Wayner

VERY interesting. I wonder why my audio distributor told me this, and why my electrician was reciting "phase A, phase B" about 100 times?

[audiogoober]

Skip the theory. Go directly to experiment:
The way to tell is:
Each outlet has a hot, neutral, and ground.
If you stick a voltmeter (suitable for Ac240 volts) into the hot and neutal you get 120 volts. Ditti the hot and ground, you get 120 volts.
If you have another line, that duplex will be the same within itself.
In they both are on the same 'leg' then connecting the two hots (using the voltmeter will give you zero volts.
If they are NOT on the same leg, then that action of using the two hots will get you 240 volts.
Ditto a third. so if you cross connect all three separate HOT runs and get zero volts from trying two hots each. AB BC AC.. then you are 100% absolute on one leg.
If any combo gets you 240 volts. you are using two legs..

That 240 volt potential IS the issue with using more than one leg of incoming power.

Added: If as JerryM suggests the circuit #28 in not on the same phase as the other two.. then that hot connected to eiither of the other two hot wires is a potential of 240 volts.

Thanks but I don't have the tools or the experience to even begin thinking about doing this. 

[kc8apf]

I found the CAD drawings for this load center on Schneider's website.  The important part is the set of schematics on the right-hand side of the drawing.  Look at the one for your load center (QO140M200C).  Breakers in the same row are always on the same hot.  The rows alternate between the two hots.  So, slots 27, 28, and 31 are all on the same hot.

BTW, this arrangement is fairly common since it allows you to install 240v breakers like this:

[audiogoober]

I found the CAD drawings for this load center on Schneider's website.  The important part is the set of schematics on the right-hand side of the drawing.  Look at the one for your load center (QO140M200C).  Breakers in the same row are always on the same hot.  The rows alternate between the two hots.  So, slots 27, 28, and 31 are all on the same hot.

BTW, this arrangement is fairly common since it allows you to install 240v breakers like this:


That's great information! Thank You.

[Glen B]

VERY interesting. I wonder why my audio distributor told me this, and why my electrician was reciting "phase A, phase B" about 100 times?

The correct term to use is 120V leg.  Both are halves of the same phase.  The use of the term "phase" is just a bad habit people have developed for use of the word to describe each leg.

[4krow]

And then if you are going to use say, an electric range that requires 240v to operate, how could you accomplish that with two 'legs' of the same 'phase'?

[4krow]

I should add that electrical panels are deceptive after the breakers are placed. I would have assumed that all the breakers on one side were of one phase, and all the breakers opposite were of the other phase. This is not true. Every other breaker from top to bottom on each side, is of the opposite phase. This makes the 220v double breakers easy to install. It confused me as well, until I saw a panel with no breakers in it.

[Wayner]

And then if you are going to use say, an electric range that requires 240v to operate, how could you accomplish that with two 'legs' of the same 'phase'?

Because they are the same phase, 2 legs of 120 volts (same phase) in series. 120 volts (leg 1) + 120 volts (leg 2) = 240 volts.

If they were of different phases, we would have an arc flash explosion. I suggest you go educate your self on how electricity is made and how it gets to your house. Try looking up an "Ugly's Electrical References" manual. It will also show all you want to know about 208 volt, 3 phase and 480 volt, 3 phase stuff.

Wayner

[4krow]

Nothin like an A hole to set you straight.

[Davey]

Some confusing and incorrect posts here.  The power that enters your house is "split-phase."  The transformer on the pole has a 240 volt secondary with a center tap that becomes neutral/ground.  It's not incorrect to think of the two "hot" legs at the top of your load center as separate/different "phases."  If you monitored each with an o-scope (with neutral as a reference) you'd see the polarities of each "leg" are 180 degrees out of phase with each other.

http://en.wikipedia.org/wiki/Split-phase_electric_power

It's a very simple system.

Cheers,

Dave.

[cheap-Jack]

Hi.

Can anyone out there please confirm if my three dedicated stereo lines are wired correctly and all on the same phase? The three stereo circuits in question are # 27, 28 and 31. Photos of the panel configuration, and SqareD model/information are attached for your review.

All USA & Canadian home powerline distribution networks employ the same single-phase 3-wire midpoint neutral system.

For audio use, I would hook up all dedicated powerlines from the same feeding line of the incoming HV duplex distribution lines. This is to ensure the same & equal HV voltage supplied to all the dedicated powerlines for yr audio. Why? Different loads of different household electrical lightings & appliances, resulting different voltage drop across each of 2 duplex feeding lining from the distribution transformer outside of yr house despite they both being in the same phase.

In yr case, I suggest you to have the dedicated powerline now hooked up #28, connected to the same 'side' of terminals rack where #27 & #31 now hooked up to. By such reconnection, ALL yr 3 dedicated powerlines are sharing the same incoming feeding line of the duplex distribution system. So same & identical voltage will be supplied to all yr dedicated powerlines for yr audio.

I'vd done it simple for my 2x 125V dedicated powelines as I only use one single larger gauge size  RW90 cable hooked up to my house contactor panel to a dedicated 125V wall outlet, from where I branched out 2 dedicated powerlnes (each with inline RFI filter) to my analogue & digital gear discretely.

c-J

[rockadanny]

OK, then since both legs are same phase, is it necessary to put all audio gear on the same leg?
If so, why?

[Elizabeth]

OK, then since both legs are same phase, is it necessary to put all audio gear on the same leg?
If so, why?

Two possible issues: First simple: grounding. the two legs may possibly have a different ground potential, or stray DC difference. WHY: you get HUM with that problem.
Second:. because of the 240volt differential which could possibly arise from using both legs in connected equipment.
The only issue with using two legs is if an accident, or short developed. A few odd bits of garage tinker sort of stuff might straight up have issues with the other leg, and inverted AC wiring job and chassis ground to neutral..
All sorts of very minor problems with only one leg, can be major problems if they land in the wrong place on a system using both legs.

Normally nothing bad would happen. It is the 'possibility' of a problem, and the damage to you and the equipment if a 240 volt issue arises.

[mcgsxr]

I don't have a tech answer, but I do have live experience with this.

As part of my basement finishing, I had a pony panel installed for the AV gear.  I have 5 dedicated lines in my media closet.  3 of them are on the same phase, 2 are on the other.

I plug my receiver into 1, the sub amp into 2, and the blu ray into 3.  I use 4 and 5 for the hard drives, netbook, logitech IR blaster and other non essential but related AC gear.

Sounds great.  No hum etc.

So, I don't think you need to plug them all into one leg.  I don't.

[kc8apf]

Hi.
All USA & Canadian home powerline distribution networks employ the same single-phase 3-wire midpoint neutral system.

For audio use, I would hook up all dedicated powerlines from the same feeding line of the incoming HV duplex distribution lines. This is to ensure the same & equal HV voltage supplied to all the dedicated powerlines for yr audio. Why? Different loads of different household electrical lightings & appliances, resulting different voltage drop across each of 2 duplex feeding lining from the distribution transformer outside of yr house despite they both being in the same phase.

In yr case, I suggest you to have the dedicated powerline now hooked up #28, connected to the same 'side' of terminals rack where #27 & #31 now hooked up to. By such reconnection, ALL yr 3 dedicated powerlines are sharing the same incoming feeding line of the duplex distribution system. So same & identical voltage will be supplied to all yr dedicated powerlines for yr audio.

I'vd done it simple for my 2x 125V dedicated powelines as I only use one single larger gauge size  RW90 cable hooked up to my house contactor panel to a dedicated 125V wall outlet, from where I branched out 2 dedicated powerlnes (each with inline RFI filter) to my analogue & digital gear discretely.

c-J

His panel isn't divided down the middle.  See the panel schematic I posted above.  Both breakers in a row (e.g. 1 and 2) are on the same leg.  Adjacent rows (3/4 and 5/6) are on opposite legs.  So, 27 and 28 are on the same leg as 31.  If 28 was moved to 29, it would be on the other leg.