# Wiring Question - 12g or 14g **URL:** \ **Category:** In My Humble Opinion\ **Tags:** tools-electric-diy\ **Created:** [August 5, 2024, 7:37pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285 "2024-08-05T19:37:42Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![OldOlds](https://avatars.discourse-cdn.com/v4/letter/o/a3d4f5/32.png) [@OldOlds](https://boards.straightdope.com/u/OldOlds)\ **Post date:** [August 5, 2024, 7:37pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/1 "2024-08-05T19:37:42Z")
I’m re-doing a room and running a whole new circuit. I’ve mentioned that nothing in the house was grounded, and as we remodel we’re fixing that. Also, this is currently frankencircuit, powering my office, the attic, and this bedroom. FWIW, I’m a pretty accomplished DIY electrician. For the new room I’ll be doing a typical 15A mixed lighting and outlet circuit. However, the home run is going to be about 100 feet from the panel to the first box. Should I use 12g for that first long run, and then go to 14g from there, or am I over thinking it? I know it’s legal to mix 12 and 14 as long as the breaker is 15A. Just wondering if 100ft is asking a lot of the 14. And if I know me, and I end up using 12 for that first run, I’ll end up doing the whole thing in 12 and make it 20A, which really isn’t necessary, but I can’t help the “bigger is always better” way of thinking sometimes. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [August 5, 2024, 7:41pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/2 "2024-08-05T19:41:51Z")
Other than the fact that 12AWG is a bit more expensive and harder to work with, I would definitely go that route with a 20A circuit. Better to have the capacity and not need it. ---
**Author:** ![OldOlds](https://avatars.discourse-cdn.com/v4/letter/o/a3d4f5/32.png) [@OldOlds](https://boards.straightdope.com/u/OldOlds)\ **Post date:** [August 5, 2024, 7:43pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/3 "2024-08-05T19:43:09Z")
Agree, although fighting with the 12g wire is surprisingly more annoying than the 14. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 5, 2024, 7:43pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/4 "2024-08-05T19:43:22Z")
Voltage drop is negligible in 100 ft for either. I’d personally use #12 for the entire circuit because ::cue ominous music:: _you never know._ ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [August 5, 2024, 7:44pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/5 "2024-08-05T19:44:36Z")
Exactly. Err on the side of too much over too little. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 5, 2024, 7:47pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/6 "2024-08-05T19:47:21Z")
[Moderating] It looks like the factual issues here are already well-known to all in the thread, including the OP, and what’s left is mostly seeking advice. Hence, IMHO. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 5, 2024, 7:50pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/7 "2024-08-05T19:50:14Z")
[Not moderating] I don’t know what the future will bring, but I know that the past century or so has seen a lot of increases in how much is expected of home electrical wiring. And if there does come another such increase in expectations, it’s a lot easier to have the wiring already in place. The downside, meanwhile, is of course that you’re buying more copper, but that’s negligible compared to the cost of the labor. So I, too, would just go ahead and overengineer it. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [August 5, 2024, 7:55pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/8 "2024-08-05T19:55:11Z")
> [@OldOlds](#): > > Agree, although fighting with the 12g wire is surprisingly more annoying than the 14. The first Covid summer I built a deck extension at the back of my garden and ran conduit so I could plug in my misting fan. I was annoyed to check the circuit to realize it was 20A but I now needed 12AWG even though it would be just a few amp draw. Being in the middle of the supply chain meltdown I could not get stranded and had to pull 3x solid wires, which was an absolute bear. ---
**Author:** ![OldOlds](https://avatars.discourse-cdn.com/v4/letter/o/a3d4f5/32.png) [@OldOlds](https://boards.straightdope.com/u/OldOlds)\ **Post date:** [August 5, 2024, 7:55pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/9 "2024-08-05T19:55:57Z")
Now, that’s interesting. I think I would argue that was true until about 10 or 15 years ago. TVs consume less power, and my 400W rack system has been collecting dust in storage- most kids these days probably don’t know what a rack system is. Meanwhile, with so much now running on rechargeable batteries, I suspect most bedrooms today draw less power than they did when I was a kid in the 80s That doesn’t mean y’all **haven’t** convinced me to do 20A… ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [August 5, 2024, 8:00pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/10 "2024-08-05T20:00:20Z")
I think that is accurate, after peaking high 10 or 15 years ago, electricity usage is trending down with much more efficient electronics/appliances. Not to mention lightning has really trend down over the last 20 years. But you never know what you’re going to end up doing in that room, so a little extra amperage is probably good. ---
**Author:** ![Seanette](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/seanette/32/9139_2.png) [@Seanette](https://boards.straightdope.com/u/Seanette)\ **Post date:** [August 5, 2024, 8:00pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/11 "2024-08-05T20:00:42Z")
I don’t know myself, but I’m married to a professional electrician. Pinging @Bob_Blaylock for his input. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [August 5, 2024, 8:04pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/12 "2024-08-05T20:04:20Z")
> [@Chefguy](#): > > Voltage drop is negligible in 100 ft for either. Many years ago I made a spreadsheet for calculating voltage drop. Here are the results for 100 feet of 14 AWG, with a current of 12 A: Branch voltage: 120 VAC RMS Conductor resistance @ 20 °C: 2.525 Ω/1000 ft Max temperature: 90 °F Modified resistance (due to 90 °F): 2.6454 Ω/1000 ft Length of run: 100 ft (One-way length of cable run) Max current:12 A Max Voltage drop: 6.35 V Max voltage drop: **5.29%** (\< 3% is considered good for branch circuits) Here are the results for 100 feet of 12 AWG with a current of 12 A: Branch voltage: 120 VAC RMS Conductor resistance @ 20 °C: 1.588 Ω/1000 ft Max temperature: 90 °F Modified resistance (due to 90 °F): 1.6637 Ω/1000 ft Length of run: 100 ft (One-way length of cable run) Max current:12 A Max Voltage drop: 3.99 V Max voltage drop: **3.33%** (\< 3% is considered good for branch circuits) I’d probably go with 12 AWG. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 5, 2024, 8:07pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/13 "2024-08-05T20:07:42Z")
Use 12 unless there’s a cost consideration. Better for future expansion, and better than the price will likely be in the future. Sometimes 15 gauge outlets don’t take 12 well. Do you know about Wago butt splices and lever nuts? They’re dirt cheap from Amazon and make life much easier. ---
**Author:** ![OldOlds](https://avatars.discourse-cdn.com/v4/letter/o/a3d4f5/32.png) [@OldOlds](https://boards.straightdope.com/u/OldOlds)\ **Post date:** [August 5, 2024, 8:17pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/14 "2024-08-05T20:17:00Z")
Funny you ask. I decided that this would be my first wago project. Despite having a lifetime supply of wire nuts. I’ve been aware of them for a while but only recently started seeing them in the store. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [August 5, 2024, 8:37pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/15 "2024-08-05T20:37:28Z")
> [@TriPolar](#): > > Sometimes 15 gauge outlets don’t take 12 well. I’ve never seen an outlet that doesn’t take 12AWG on the screws. Do you mean the backstabs? Code approved or not, I’ve always heard it is bad practice and never use them. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 5, 2024, 8:46pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/16 "2024-08-05T20:46:51Z")
Oh, sure, right this moment, the specific new tech has been lower-power lights and entertainment devices, and so right now, power demand is going down. But who knows what’s around the corner? Maybe 50 years from now, we’ll all have replicators or medbeds or something that we can’t even dream of now. And maybe they’ll need more than 20 A and you’ll need to rewire anyway, or maybe all they’ll need is a single USB-E port for power, in which case… you’re out the cost of the extra copper. Or maybe you’ll be really glad you put it in. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 5, 2024, 9:02pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/17 "2024-08-05T21:02:48Z")
> [@OldOlds](#): > > For the new room I’ll be doing a typical 15A mixed lighting and outlet circuit. How many outlets are going to be on this circuit? If it’s a lot then you might want to consider splitting it into two circuits while you’ve got the chance to run new wiring. Then again, if that requires two 100ft runs that could get a bit pricy. 14 AWG is acceptable per code in this case, but like most of the others in this thread, I personally would use 12 AWG. > [@FinsToTheLeft](#): > > Do you mean the backstabs? I hate backstabs with a passion. I would never use one in my house. Yeah, technically they are legal and to code, but no. Just no. Personally I don’t think 12 AWG is all that difficult to deal with. Then again, I work in industrial controls and we use a lot thicker wire than that on a regular basis, though usually when I’m on site it’s an electrician that’s doing the actual wire work. I only wire up test things in our lab. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 5, 2024, 9:06pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/18 "2024-08-05T21:06:29Z")
> [@FinsToTheLeft](#): > > Do you mean the backstabs? Only the backstabs I can recall specifically as a problem. I just don’t trust them to hold over time. ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [August 5, 2024, 9:18pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/19 "2024-08-05T21:18:31Z")
> [@TriPolar](#): > > Only the backstabs I can recall specifically as a problem They are only rated for 14AWG, but as I said I won’t use them for anything. ---
**Author:** ![echoreply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/echoreply/32/3641_2.png) [@echoreply](https://boards.straightdope.com/u/echoreply)\ **Post date:** [August 5, 2024, 9:26pm UTC](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285/20 "2024-08-05T21:26:25Z")
Instead of backstabs, can’t you just spend $2 more per receptacle and use the commercial kind with the clamps? 90% as easy as backstab with none of the downsides, or so I’ve been told. Making a similar decision, I had the electricians run 4AWG for 60 amps instead of 6AWG for 50 amps. Way more than I need, but if I ever want two EVSE, I’m set. [Next page](https://boards.straightdope.com/t/wiring-question-12g-or-14g/1005285.md?page=2)