(not a journeyman) It depends on what you mean by a junction box. If it's just a box in the wall: avoid changing it. Run a new line. Just pull your copper and be done with it and add an outlet. An inspector probably won't notice, but you are going to get shouted at less if the box doesn't look like a hot mess. I also believe that your box has a rating on it, and you can't put more current in it than it's rated for, and that rating should be around 20 amps. If you want to do what I think you want to do, you will exceed my guess of the rating. If you are going to be pulling a ton of current then you should preferably avoid splices if you don't have to use them. Remember to turn off the main power before you open the box. Please don't cook yourself

The issue is I believe the box is neither the beginning of the circuit or end. I don't know the outlet path throughout the floor. I know for sure two lamps (only LED bulbs) are on it because they dim for a brief second when the PC is turned on.

The wires should be in the wall. It is more expensive, but you will be saving yourself a huge headache by just running a new line

That was definitely my intention, leave what's there in place and run a new line but wasn't sure what code wise was needed. In another post someone said use a Dual gang which would be more visually appealing than a second outlet and capping the original.

Replacing a box is a lot harder than adding one. You run the risk of breaking wires because copper doesn't like to be bent a lot. Run a new line to code (drill and staple every stud) and add another box where it would be close to where you want it. If you put the box on the next stud over it should look better than right on top of the old one

Are you an apprentice? No offense, but I'd refrain from giving advice until you get further along. Assuming you're in the US anyways.

>I also believe that your box has a rating on it, and you can't put more current in it than it's rated for, and that rating should be around 20 amps.

Boxes don't have current ratings. There's no current running through boxes. They do have fill limitations however, based on number of devices, connectors, and conductors.

>If you are going to be pulling a ton of current then you should preferably avoid splices if you don't have to use them.

13 amps isn't a ton of current, and sure, it's better overall if you avoid splices because it's one less potential point of failure. But if you're concerned OP's splices can't handle 13A, they shouldn't be doing any electrical work whatsoever. Any good splice should have better ampacity than the conductor itself.

What you're describing is fine as long as there aren't box fill issues, and pretty standard.

Hey do you self a favor, just leave that box alone!
just cut in a new box a few inches away at the same height and run yourself a new romex 12-2 and put it on a new 20amp breaker you’ll have your dedicated circuit and you’ll have the original still intact if that doesnt work for you then take existing box out of the wall and put in a two gang box put existing circuit back together on 1 side and your new 20amp circuit on the other.

I have to keep the original. It's definitely inline with other outlets since it causes my living room lights to dim when I turn on the PC

No. I'm basically retired. So you avoided not insulting me. I'm under the firm impression that this person is going to do it with or without good advice. Since we don't know the exact box, because they are especially green and they are obviously confusing a junction box with an outlet box, what I suggested is the safest way just as you confirmed. So... Since they are probably pretty set on doing it themselves, they should not be terrified because that makes mistakes, but they shouldn't be overconfident because they won't see mistakes. Can that circuit handle the current as it is? It's close, but it falls under 80% with nothing else drawing current under the written load requirements. Should they call an electrician? Absofukinlutely, but I'll bet cash they won't. Anything I can do to keep someone from getting bit, or worse, is what I am aiming for. The safest way for them to accomplish their goal is to pull a new line. Safety always.

It seems like you have a lot to learn about how a normal person can screw up electrical shit, especially with joining wires. Solid conductors require a lot of married length to get the conductive surface area for the splice to have less resistance (or ampacity? Wtf) than the conductor. So if they are in the US they probably shouldn't be using twist connectors unless they have seen some burnt and melted so they can see how not to use them. A single run will prevent the possibility of messing up a join. Safety always.

10 milliamps is enough to make muscles uncontrollable. 1 amp can easily start a fire. 13 amps is actually a lot of current. You are probably used to dealing with 3 phase panels so it's not a big deal. When Harry the homeowner starts getting the idea about putting 20 amps in a wall, it's best for them to have it in their head that it's a sizable amount, because it is. Safety always.

At the very beginning I stated that I wasn't a journeyman, which if you were worth your salt, you would have put that bit together. So before you start attacking my experience with people who mess up projects and my intelligence, maybe you should have first checked to see if electrical boxes have current ratings... Because they do. Don't be pedantic to bring me down, just to feel smart, or appear more helpful. You should be worried about them. I'm not the one you should be working on. Keep your eyes on the danger. Safety always.

Actually help them if you want to one-up me. Go over. Pull the line. Be done

Wasn't trying to insult you, when you said you weren't a journeyman I just thought you might be an apprentice.

> Can that circuit handle the current as it is? It's close, but it falls under 80% with nothing else drawing current under the written load requirements.

Never said they shouldn't pull a dedicated circuit, they absolutely should.

>It seems like you have a lot to learn about how a normal person can screw up electrical shit, especially with joining wires. Solid conductors require a lot of surface area for the splice to have less resistance than the conductor. So if they are in the US they probably shouldn't be using twist connectors unless they have seen some burnt and melted so they can see how not to use them. A single run will prevent the possibility of messing up a join. Safety always.

I've seen plenty of failed splices. And in my opinion, if you can't aplice properly, you shouldn't be doing electrical work. But you're taking the harm reduction approach, and that's fine too. It just reads as odd advice on my end.

>10 milliamps is enough to make muscles uncontrollable. 1 amp can easily start a fire. 13 amps is actually a lot of current. You are probably used to dealing with 3 phase panels so it's not a big deal. When Harry the homeowner starts getting the idea about putting 20 amps in a wall, it's best for them to have it in their head that it's a sizable amount, because it is. Safety always.

My point was that 13A is boilerplate, basic electrical work, and if they can't handle that then this is outside of their capabilities.

>At the very beginning I stated that I wasn't a journeyman, which if you were worth your salt, you would have put that bit together. So before you start attacking my experience with people who mess up projects and my intelligence, maybe you should have first checked to see if electrical boxes have current ratings... Because they do. Don't be pedantic to bring me down, just to feel smart, or appear more helpful. You should be worried about them. I'm not the one you should be working on. Keep your eyes on the danger. Safety always.

Wasn't trying to insult your intelligence. Apparently boxes have current ratings in the UK, I don't know if that's where you are. But in the US, boxes absolutely do not have current ratings. Here's a link to a cutsheet with common residential boxes. Ampacity isn't mentioned once, because box volume is how you keep a box from overheating, not branch circuit ampacity.

I used a newfangled calculator, as you didn't directly instruct me to do, and I can apparently run, splice, and dead short an embarrassingly irresponsible amount of current through a $1 plastic box. I just looked up some boxes, outside of your link, and I concede that the rating is no longer applied? WTF. I'm getting old, cranky, and I'm wondering who bribed who... Because back in my day one would get their lunch break disappeared if a run capacity was more than what was LITERALLY on the label for the box (every one had better have been 20 amps per gang or your ass was driving back to the store). What written word is keeping some nutbag from pulling 100 amps through a single gang box? That terrifies me. The only rating I found, in amps, was for a junction box in the UK (pedantically not in Europe), but that isn't for the enclosure it is for the screw terminals that are basically molded in.

At this point it's safe to say that I'm scared for the children, and I'm a cranky old man.

Your calculator is wrong. Max you can bring into a single gang box with a device is 8awg, 40 amps. Max you can splice and continue through is 10Awg, with no device. Also, I said UK, not Europe.