What exactly is a 20 amp dedicated line?

Jea48, Just to clarify,

Did you mean to write "seperate legs" of the power box, when you wrote 'It is...not be fed from separate circuits...
04-21-13: Mesch

Mesch,

Not sure what you mean. Could you copy and paste the portion of my post you're are referring to.

This?

The 2 hot conductors must be fed from opposite Lines, legs, of the electrical panel.
04-19-13: Jea48

This may help.
Click on, Single-phase power systems.
>http://openbookproject.net/electricCircuits/AC/AC_10.html#xtocid174140

Jim

Jea48, Just to clarify,

Did you mean to write "seperate legs" of the power box, when you wrote 'It is...not be fed from separate circuits...

Thanks

Hcbravesfan,

If you use a 3 wire with ground romex (NM-B) for the purpose of creating 2 circuits what you end up with is a multi wire branch circuit.

With a 3 wire multi wire branch you will have 2 separate circuit,(not 2 dedicated circuits), with a shared neutral conductor.

The 2 hot conductors must be fed from opposite Lines, legs, of the electrical panel.

When a multi wire branch circuit is fed from a single phase, split phase, secondary winding of a transformer only the unbalanced load of the loads connected to each separate circuit will return on the neutral conductor.

Example, if a connected load of exactly 5 amps each is connected to each 120V separate circuit, 0 amps will return on the neutral conductor to the source. The two 5 amp 120V loads are in series with one another.

Example, if 5 amps of load is connected to one 120V separate circuit and 2 amps of load connected to the other separate circuit, then 3 amps (the difference of the two) will return on the neutral. The balanced 2 amps will be in series with one another.

It is obvious why audio equipment should not be fed from separate circuits whether connected together by ICs or not.

Why would you want to series hash from digital equipment right out of the power cord right back into the power supply of an analog preamp or phono preamp.

With true dedicated branch circuits that have their own hot, neutral, and equipment ground conductors the dedicated circuits should be fed from the same Line, leg, from the panel when the equipment is linked together by ICs. I would even go so far to say HDMI cables as well. Though I have not read any info on such regarding HDMI cables..... Must be something out there.

Added note.
Per NEC, the 2008 edition, all multi wire branch circuits shall be fed from a multi pole common trip handle breaker.

If you are trying to get 2 dedicated lines with one romex I'm assuming he is speaking of using 12/3 with ground. or 10/3 ...(same)...If you keep each hot on the same Phase in the Main Elect. panel then at your point of contact to your receptacle (in the J-box, at the stereo) there would be no way of accidentally ending up with 220 volts. Wiring is No Hobby, Call a professional. And I'm not trying to be a smart-ass with that comment either...

now the really important question is what's a Porter port? Drawing a slack jawed zero over here!

....

is the NEC the National Electrical Code?

Yes.

Second, if a multi wire branch circuit is set up in the manner I described above, please explain how a multi pole branch circuit breaker works.

The multi pole breaker has the function of controlling all of the circuits of a multi wire branch circuit simultaneously. NEC Code changes mandated that all circuits of a multi wire branch must be de-energized by a one handle action. All on or all off. Pre-code change, individual single pole breakers were used. It is a safety thing for an electrician or maintenance person that may be working on one or more of the circuits of the multi wire branch circuit.

In commercial and industrial buildings 3 phase 4 wire multi wire branch circuits are quite common.
(3) hots, (1) neutral, and (1) equipment ground.

For example, if each hot energizes a separate receptical, is it possible that a short or overload of one receptical fed by one hot would NOT trip the breaker for the other circuit fed by the other hot?

That is true where a single pole breaker is used for each circuit of a multi wire branch circuit.
That is not the case when a multi pole breaker is used. In the case of a 3ph 4 wire multi wire branch circuit a 3 pole breaker must be used for the overcurrent protection of the branch circuit.

If one of the circuits of the three was overloaded the breaker will trip open and take the other two circuits with it.

Multi wire branch circuits are a thing of the past now..... At least in jurisditions that approved that part of NEC.

A dedicated line starts from the electrical panel and ends at only one location. The outlet can be any configuration, single, dual or quad.
Most outlets in your house say in your livingroom are daisy chained and lead to more than one outlet in differant locations.

Thanks Jea48 for the info. Please clarify a couple of points you made. First, is the NEC the National Electricans Code?

Second, if a multi wire branch circuit is set up in the manner I described above, please explain how a multi pole branch circuit breaker works. For example, if each hot energizes a separate receptical, is it possible that a short or overload of one receptical fed by one hot would NOT trip the breaker for the other circuit fed by the other hot? If such is the case, isn't that the practical equivalent of 2 dedicated lines?

BTW, for the benefit of others, if a multi branch circuit is legal under applicable Codes and safe, the reason that it could mess up a stereo system is because the AC current is alternating in opposite phases in each hot. That is how 220 v is obtained. I know this because I was an electrician's assistant when I was in college back in 1970. I remember that a 220 v shock can knock your fillings out -- and if that's all that happens, you're da*n lucky.

However, as far as the specific electronic consequence of mixing and matching different phase circuits in stereo gear is concerned, I'll leave that discussion to the electronics techies out there if they think it's worth a comment or two.

Thanks again.

Bifwynne,

Yes, it is called a multi wire branch circuit. (Two 120V separate circuits.) Not two dedicated circuits....

Not so good for audio equipment that is connected together by ics though.

In 2008 NEC required that multi wire branch circuits must be fed by a multi pole branch circuit breaker. Too many electricians were being killed from an open neutral....

WOW! I think that I bit off more than I can chew from the responses above. Thank you very much for all of the information.

Jea48, do you know if it's Code to run a single 220v romex line consisting of 2 hots, 1 neutral and 1 ground into a single receptical box, with each hot powering a separate receptical and the single neutral and ground doing double duty for the two recepticals? I assume that each hot would be connected to a separate breaker in the fuse box. If Code, this would be an efficient way to run 2 dedicated lines with one romex run.

Of course, the polarity of each receptical would be inverse to the other if powered by the 2 hots.

What exactly is a 20 amp dedicated line?

A line that is dedicated for a specific purpose.

A 120Vac 20 amp dedicated branch circuit consists of,
(1) Equipment grounding conductor
(1) Neutral conductor
(1) Hot conductor.

A true dedicated branch circuit does not share a cable or raceway with any other branch circuit/s.

How many receptacles are connected to the branch circuit depends on what was specified by the customer or manufacture of a piece of equipment.

A single receptacle could be specified.

A duplex receptacle.

Two duplex receptacles.

One duplex is quite common.....

What did you specify when you hired the electrician?

Note.
Per 2008 NEC code if a duplex receptacle is split and fed by two branch circuits the breakers feeding the duplex receptacle shall have a common tie handle so both circuits can be de-energized by one handle.

You can have it both ways; a dedicated line can be used with both outlets, or you can break the tabs connecting the upper and lower outlets and have a seperate dedicated line to each outlet, giving you 2 dedicted lines. With a dedicated line, no other outlets are on the line except the one you will be using.