Dedicated Outlets - The Latest Recommendations


This topic has received a lot of attention over the years, but I'm having trouble pulling all the pieces together so that I can communicate to the electrician exactly what it is I'd like to have done.

I'm hoping to add two separate, 20 amp lines for my audio equipment, and since we are having our roof redone, this presents an ideal window for a project like this.

The service panel is on the lower level of the house near an outside wall, and the lines would come up the wall, travel across the space above the ceiling and under the roof (roughly 12 inches), and then down an inner wall to a room on the upper level.

I'd like to know what type of wire is best to use (the total distance from panel to outlets is about 75 feet), how it should be attached to the service panel, and what type of outlets are recommended.

I recall seeing advice in the forums to use twisted wire to reduce hum and EMI, and not to have the two runs too close to each other.

Any advice for specifying specific materials, and communicating with a non-audiophile electrician would be greatly appreciated!

And I'm hoping Jea48 and other knowledgeable members will chime in with either sage advice, or links to relevant sections of past discussions.  Perhaps we can make this thread a starting point for others contemplating similar projects.
rel
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If you look for an electrical contractor that does commercial work, not just residential, you may already be in the ballpark in terms of dealing with some of this stuff (less arm-twisting). At least that's been my experience. Good luck.
I went through the same gyrations recently.  Here are a couple things to consider:

Use a panel that has a copper bus bar.  The only commercially available panel I found that fits the bill is a Square-D QO series panel.  The QO panels are more for commercial use...the copper is "tinned" so it will not look like copper though.  All other panels I looked at had aluminum bus bars, including the Square-D Homeline series.

Your electrician will really fight you when you tell him to put all circuits one one leg but stay strong!  FYI, in many panels each leg alternates from slot to slot on each side.....each side is not necessarily on one leg or the other.

One thing I did not do, that I suppose I could have, was to run 10-3 Romex instead of 10-2.  10-2 has two insulated legs and an uninsulated ground.  10-3 has three insulated legs and an uninsulated ground.  Some people recommend 10-3 and using the 3rd insulated wire as a ground and not using the uninsulated leg.  Supposedly it is possible for the uninsulated ground wire to act as an antennae for RFI.  Just something to chew on.  One caveat....10-3 is very very stiff.

Lastly, one thing I'd like clarified from someone else....How do you define a sub-panel?  We ran a dedicated panel for my audio circuits directly off the meter loop and gave it its own ground.  When I hear "sub-panel" I assume this means it is tapped off the main panel.

Good luck!
Corrections / Clarification:


If you can use NM-B cable (Romex is a trade name) that seems to be the most popular. If you use NM-B cable have the electrician use plastic outlet boxes instead of steel boxes if possible.
Have the electrician keep the NM-B cables separated from one another when parallel to one another for long distances. Also try to keep them from other parallel branch circuits after he gets out the the electrical as soon as possible, within reason. Especially lighting branch circuits. (Dimmers, electronic ballasts, CFL lamps, LED lamps. All radiate RFI harmonics through the air.)
Should read:
Also try to keep them from other parallel branch circuits after he gets out *of* the electrical *panel* as soon as possible, within reason.

.

Because of the 75ft length of the branch circuits I would use #10awg solid core copper wire. Don’t let the electrician talk you out of it. Don’t let him try to talk you out of using solid core wire either. He will tell there is no difference between solid and stranded wire. LOL, for him there is, Stranded is easier to work with. Expect to pay a slightly higher labor cost though.
Should read:
He will tell *you* there is no difference between solid and stranded wire.
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If conduit is used ask the electrician if he will twist the hot and neutral conductors together the entire length of the conduit run and pull the insulated equipment grounding conductor in the conduit along side the hot and neutral twisted pair. If he can not or will not, then there is a very good chance, high probability, with a 75ft run of conduit with the hot and neutral wires pulled loosely in the conduit with the equipment grounding conductor wire you will have ground loop problems, 60Hz hum.

I should have added, though I have read the benefits of twisting the hot and neutral conductors together prior to installing them in an empty conduit it may not meet electrical code requirements. I have looked at the NEC and have not found anything that directly prohibits twisting the hot and neutral conductors together and then pulling the twisted pair in a conduit. That doesn’t mean it isn’t in there somewhere though. Bottom line, is it allowed by the AHJ (Authority Having Jurisdiction) electrical inspector in your area? He/she has the final say. Period.

Jim
whart
1,252 posts                                                                      09-27-2017 2:17pm

If you look for an electrical contractor that does commercial work, not just residential, you may already be in the ballpark in terms of dealing with some of this stuff (less arm-twisting). At least that’s been my experience. Good luck.
Bill,
I agree.

Jim