Time for dedicated outlets!
@mizike, Pay close attention to pages 31 through 35. https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf |
There are also different grades of breakers depending on the manufacturer of your panel.Per NEC only the panel manufacture breakers can be used in the panel. Breakers Listed for use in the panel are listed on a label found inside the panel. Usually on one side or the other +3 for 10/3 romex.What do you do with the bare #10 ground wire in the Romex cable? |
cerberus79 14 posts 05-06-201710:40am Early in this thread is was recommended that 10-3 with ground be used instead of 10-2 with ground for a single 120V 20 amp dedicated branch circuit. The idea is to use one of the insulated conductors for the equipment grounding conductor instead of bare equipment grounding conductor. (I assume the red would be rapped with green marking tape to identify it as the equipment grounding conductor.) I assumed the above wiring method is what falconquest was referring to in his post, that I responded to. So my question, What do you do with the bare #10 ground wire in the Romex cable? |
@cerberus79, Run a 12/3 romex that is a neutral with two lines and a ground. This will give you two dedicated 20 amp cicuits with one run.No, that would be 2 separate 120V circuits. A 3 wire 120/240V multiwire branch circuit. Two separate 120V circuits with a shared/common neutral conductor. A 120V dedicated branch circuit is a branch circuit with a dedicated, Hot conductor Neutral conductor Equipment grounding conductor. A true dedicated circuit does not share a raceway, conduct, or cable assembly, with any other circuits. Multiwire branch circuits are not recommended for feeding audio equipment. Especially where audio equipment is connected together by signal wire interconnects. It also should be mentioned the 2 circuits of the 120/240V 3 wire multiwire branch circuit must be connected to a 2 pole breaker, per NEC. Only the imbalanced load, of a 3 wire multiwire branch circuit will return on the shared neutral conductor back to the source, the electrical panel. The balanced load of the 3 wire circuit is in series with the two hot ungrounded conductors. Example: If the connected load on L1 to neutral is 5 amps and the connected load on L2 to neutral is 5 amps, zero amps will return on the neutral conductor of the branch circuit back to the source. The two loads are in series with one another, essentially being fed by 240V. So say Digital equipment is fed from one of the separate 120V circuit outlets and the analog is fed from the other separate 120V circuit outlet, Only the imbalanced load of the digital equipment and analog equipment will return on the neutral conductor. The balanced 120V loads, of the two connected loads, will be in series with one another. Do you really want the digital hash going back out on the power cord/s of the digital equipment coupled to the power transformer/s of the analog equipment? Here is a very good video on how a multiwire branch circuit works. https://www.youtube.com/watch?v=eVamt9IdQd8 . |
cerberus79 17 posts 05-06-2017 9:09pm Multiwire branch circuitshttp://ecmweb.com/code-basics/branch-circuits-part-1 "single-pole circuit breakers with handle ties identified for the purpose" The tie used must be a Listed tie for the intended purpose. Or, just use a 2 pole breaker...... Or, in the case of a 3ph. 4wire multiwire branch circuit a 3 pole breaker. Just going from memory I believe this was added to the 2008 NEC. After State and local AHJs adopted the new language, at least in my state, the 120V as well as 277V multiwire branch circuit became a thing of the past. I don’t know of anyone that installs them today, or for the last 8 years. Best regards, Jim |
@cerberus79 Please read the first 36 pages of this white paper. https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf quote from page 31 The “Conduit Transformer”• This finally explains what drives 99% of all ground loops! •Load current in line and neutral produces opposing magnetic fields since instantaneous current flow is in opposite directions •Imperfect cancellation magnetically induces voltage over the length of the nearby safety ground conductor •Strongly affected by geometry and proximity of wires •Highest voltages with randomly positioned wires in conduit •Lower voltages with uniform geometry of Romex® •Voltage is directly proportional to load current, wire length, and rate of change in current or ∆I/∆t •Mechanism favors high-frequency harmonics of 60 Hz •For constant current in L and N, induced voltage rises at 6 dB/octave . |
