Help with DIY dedicated circuit


I am wanting to install a dedicated circuit for my amp, but getting from my panel to the wall behind my amp is going to be difficult. As I was investigating in my attic, I realized that when I changed my stove from electric to gas, the unused 30 amp Romex 10/3 wire will reach within 15 feet of where I want the wall outlet. Do I install a junction box and run Romex 10/2 to the new wall outlet and use the 30 amp breaker? What is the best way to connect the wires in the junction box?
128x128jonandfamily
Your stove should be on a 40 amp circuit, which requires 8/3 Romex cable. Change the breaker from the 40 amp twin breaker to a 20 amp twin breaker then make the stove receptacle box a junction box where you splice some 12/3 Romex to the 8/3 Romex and then run the 12/3 to a duplex 20 amp receptacle with the tie on the hot side removed. This will give you two 20 amp receptacles. 
It is definitely a 30 amp twin breaker with 10/3 (orange) Romex. Do I need to change it to a 20 amp breaker? Is it ok to use the 10 gauge wire with the 20 amp breaker to a 20 amp Porter Port outlet?
You can use 10/3 with a 20 amp you can always go larger gauge but never go smaller. 
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So I will change the 30 amp twin breaker to a 20 amp twin breaker. If I install two 20 amp Porter Port outlets and use 1 hot of the Romex 10/3 to each outlet (red and black) sharing the common white wire, will that defeat the purpose of having 2 dedicated 20 amp circuits. By the way, the stovetop was a cheap radiant electric cooktop and was a piece of crap.
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A word to the DIYer re: DIY electrical mods

check with your insurance company first...

You may require a licensed electrician sign off or risk voiding your insurance policy.
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If you have to ask how to connect wires within a junction box I’d suggest getting professional help.

Best of luck


Peter 


You're not suppose to use the same neutral wire for 2 seperate breakers you can for a double pole since any overload on the neutral will trip both. 
You also need to make sure the new 20amp  double pole is on different phases in the panel box. It should be if the old 30amp was installed correct. 
pbnaudio....the physical wire connections are not what I'm asking about. I am comfortable with that. I'm asking whether to use the 30 amp twin breaker and the 10/3 cable that is currently in place (too short to reach wall outlet) with a piggytail from a junction box I'll install to the outlet, or I'll have to pay significantly more to have an electrician run a new 20 amp line from the panel to the wall. Also, could I install 2 independent outlets without running a separate cable since there are 2 hot cables with the 10/3? It appears best to change the 30 amp twin breaker to a 20 amp breaker since it will be serving a 20 amp rated outlet.
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mental522

@djones...you are very mistaken, he’s running two circuits using the same neutral. Two single pole breakers should be used, one for each circuit. A double pole breaker is designed to use different phases, all he has to do is put the single poles back in where the double pole is. I suggest you stop giving out electrical information, you are clueless.

@mental522
The National Electrical Code permits multiwire branch circuits, but adds requirements to make them safer. Section 210.4(B) states that in the panelboard where the branch circuit originates, all ungrounded conductors must be provided with a means to disconnect them simultaneously. This is usually a double-pole breaker, but two single-pole breakers may be used if they have an identified handle tie.
https://www.jadelearning.com/multiwire-branch-circuits-nec-210-4/

Mike Holt on multiwire branch circuit
https://www.youtube.com/watch?v=_VjZ5ySblew
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Not sure if it was suggested, but you could run 12/3 and have 2 separate 20 amp outlets. :) Get an electrician to do it.

If it were me, I’d use 15 amp breakers with spark detectors. You don’t need 20, and 15 will be safer. There’s no audible difference. Also while there ask the electrician about a whole panel surge protector.

Also, in some high-heat areas, you may need to underrate your wiring anyway.


Best,
E
I also recommend an electrician.  One of the comments indicated to make sure both of the "HOT" wires to your two new outlets are on the same phase.   Your stove ran on "220/240 Volt" which means that, in the United States, the two "HOT" wires are just 120V that are out of phase.  When you wire these to the stove, the stove uses both 120V in a push/pull configuration.   You really should have an electrician do the work because you want either one single 20A breaker with both "HOT" wires leading out of that.  Or you could install two 20A single that are BOTH ON THE SAME PHASE to connect to your two "HOT" wires  of your romes 10/3.  However, there are definitely electrical codes to follow and I'm not sure of this particular configuration.  So, again, I highly recommend an electrician do the work and discuss the options with you.
Read your own link jea48 it clearly states to use 2 PHASES ,  I suggest you quit giving advice you are past clueless. If he puts 2 20amp breakers on the same phase using the same neutral wire then the neutral could carry 40amps  his 10/3 existing wire is rated for a 30 amp load which could cause the neutral wire to overheat causing a fire. The breakers need to be on seperate phases where they balance and the neutral carries the difference between the loads, on the same phase the neutral would carry the sum of both.  You can use 2 seperate 20 or 15 amp breakers running one hot black and one hot red  and both use the same white neutral as long as those breakers are NOT on the same phase. Code is to use a linked 2 pole breaker IF it's a 240v  single phase OR multi- wire branch circuit with a SHARED  neutral. The OP needs to call an electrician mental is right  to much nonsense to confuse him. 
After all this and watching the YouTube link, I am more confused. If I do the work, I think I will use the 10/3 wire that is in place already, but change the 30 amp twin breaker to a 20 amp single breaker only using one of the hot cables and capping the other on both ends. I'll piggytail either a 10/2 (will it fit in the wall outlet?) or a 12/2 cable from the junction box to only one 20 amp outlet and forget about installing 2 outlets at this time.....or I'll get an electrician....
Pigtail with 12/2 it's easier to use and is fine for a 20 amp receptacle. Most likely the old 30 amp breaker is on 2 phases and you would be fine running 2 new breakers but unless you know for sure do what you said. 
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djones51
313 posts 10-08-2018 11:59am

Read your own link jea48 it clearly states to use 2 PHASES , I suggest you quit giving advice you are past clueless.
@djones51

HUH?

Is your username mental?

I suggest YOU reread my previous post. mental didn’t have any problem understanding it was directed at him.
.
Sorry he deleted his posts it looked as though you were directing it to me as I didn't see his post. I can see I made a mistake going back and reading it again. 
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@djones51 is correct in his last post, except for the terminology of phasing. In residential electrical systems, it is actually called “split phase”, which is because the utility supplies only one leg of a three phase feed, via a center-tapped secondary on a step-down transformer, where the center tap is considered the neutral conductor, and bonded to ground at the main service panel.
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mental
529 posts                                                                      10-09-2018 6:42am

@Jea...all you did was google nonsense that you yourself do not understand.

You cherry pick portions of the conversation, google, and act like you come up with a correct answer. You did not, all you did was create more nonsense.

Like I said, done with this silliness, but I will remember..
Yes I used Google. It beats the hell out of a lot of typing. Copy and paste... Was any of the info wrong? NO!

What NEC code edition are you using? I am using the 2017. The NEC 2008 added 210.4(B) which requires,
Disconnecting Means. Each multiwire branch circuit shall be provide with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates
Right out of the NEC 2008 book mental. Again what was the last NEC Code book you used?

You cherry pick portions of the conversation, google, and act like you come up with a correct answer. You did not, all you did was create more nonsense.
Nonsense huh? If you are going to give the OP advise on how to do his own electrical wiring you should at least give him info that meets Code. Technically, depending on the AHJ where he lives, he may not even be able to use his existing multiwire branch circuit for his application. Good chance the AHJ in his area adopted the NEC requiring AFCI protection of 120V 15 and 20 amp branch circuits that he wants to install. Also there is a very good chance Tamper Resistant receptacles are required.

In closing I would be more than happy to match wits on my knowledge of the NEC with yours.

Best regards.
Jim
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lmbo @ match wits with me? You're foolish. You have now been deemed google jea....you have a good day there, mr google jea
Had you been so knowledgeable you would have known what to do, but chose to copy/paste from google.
Then you have the audacity to come back and act like you're journeyman, or passed the masters exam, which by the way 90% business over the code. Too funny
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jea48 "Again, what was the last NEC Code edition book you hand in your hands"
It is so funny when one person uses Google to pretend to be an expert meets another person who uses Google to pretend to be an expert and then they both try to convince themselves and the other that he is an expert!
@clearthink...lmfao

This turned into a pee contest, sorry folks, I do NOT do pee contests any longer.

Y'all have a good day.
mental

@djones...you are very mistaken, he’s running two circuits using the same neutral. Two single pole breakers should be used, one for each circuit. A double pole breaker is designed to use different phases, all he has to do is put the single poles back in where the double pole is. I suggest you stop giving out electrical information, you are clueless.
@mental,

You just won’t admit you were wrong, will you? You said djones was clueless on the subject. Turns out he was right and you were wrong. You just refuse to fess up you were wrong.
Yeah, 2 single pole breakers can be used for a multiwire branch circuit providing an approved breaker tie is used linking the two breakers together. Do you know why 210.4(B) was added to the NEC 2008 Code?

If you are going to give out free professional electrical wiring advice, ( you stated you are an electrician), on a public internet forum I suggest you get your facts straight.

.
For those who may not be aware, the many posts Jim (Jea48) has provided here over the years about electrician-type matters make it abundantly clear that his background and expertise in this area are second to none. Second to none not only at Audiogon, but I would feel safe in saying among electricians everywhere.

I for one have learned a great deal from his posts over the years, despite the fact that I have a very extensive background in electronic design. And the help he has provided to a great many members here has earned widespread recognition and appreciation.

Regards,
-- Al 
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Seems I owe an apology to several in here. It happens, my turn to eat crow.

Lesson learned, NEC updated, probably a couple of times since I was in the field. With that said, I'll have to double check any advice I try to contribute.
I feel like the village idiot...lulz. My apologies to those I had conflict with.
@mental

Apology accepted.

Just a guess the last NEC code addition book you were using before you retired was the 1999. The NEC really started changing and adding things in the 2005 edition. Even more changes in 2008, 2011, 2014, and 2017. Probably the most changes in 2008 and 2014.

Jim
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Done! 20 amp breaker. I went with Romex 10/2 from junction box to a single Porter Port outlet which was a little frustrating manipulating the 10 gauge solid copper connections. I decided against 2 outlets at this time since all my gear is connected to a PS Audio P10 Power Plant. Now, to see if I can hear a sound difference.
Nice thread -Jon,
I look forward in reading more about your aural impressions, thoughts, post-installation of 20A breaker and Porter Port outlet.

Happy Listening!
A definite, noticeable, small incremental improvement with the dedicated circuit. I was skeptical because I thought the PS Audio P10 should be able to produce near perfect power from what comes through most any wall outlet. Voices and instruments float a little more distinctly into position and sound-stage is a little deeper. I was already very happy with the sound of my system, so I never expect big changes with these tweaks. I do think it was worth the effort.