Maybe you're thinking;
"I can't really finish my basement on my own, because I don't know how to do electrical stuff. I don't even know what wire to buy!"
You say "stuff" because you really don't have a clue what it's all about.
Well... I would say back to you - "That's a really lame excuse." You haven't even investigated it yet.
You haven't read an article like this that reveals to you this 1 simple fact:
You only need 3 wire types:
14/2 - The White Wire - used for wiring lights and light switches
12/2 - The Yellow Wire - used to wire plugs
14/3 - Same as 14/2 but with an extra red wire in it so you can control the same lights with 2 different switches (like for hallways and stairs)
THAT’S IT! That's all you really need to know!
What Does It All Mean Though?
Here's a standard 14/2 strand of Romex electrical wire
Both 14/2 and 12/2 wire types have 3 wires wrapped in "sheathing". Yellow sheathing for the 12 gauge. White sheathing for the 14 gauge.
Wire 1: The white wire. This is the neutral wire.
Wire 2: The black wire. This is the "hot" wire.
The copper wire, this is the ground wire. (they don't count this one, hence the 2 instead of 3)
All of the wires are made of copper but two of them are coated in white or black insulation because they actively carry an electrical charge. It's kind of stupid but because of this "they" ignore the grounded wire when counting them… thus 12/2 and 14/2 instead of 14/3 or 12/3. Sometimes the ground has brown paper sheathing around it, other times not. (I don't know why.)
12 gauge wire (the yellow one) is thicker than 14 gauge. Since it's thicker it can handle more "load". Because things that you plug-in like TVs, stereos, etc. tend to use more electricity than light bulbs, plugs are typically wired with 12 gauge. You could also wire your plugs with 14/2 if you wanted to. (assuming your local code allows for it)
Technically you could also wire your lights with 12 gauge wire. The only problem is it's thickness makes it really hard to work with. Twisting it can be difficult and with lights and light switches, there's a lot of twisting, sometimes 3 or 4 wires together.
Professionals - maybe you guys do that all the time? Little baby hands like me, I go with 14 gauge (the white wire) for my light circuits.
Here's what I did to wire my basement:
- I did some test wiring first. I extended the existing pull-chain lights in my basement by adding on a few recessed lights. That's how I practiced what I had read in the books.
- Once I got the hang of it I ran the wiring for all the plugs and lights. Nothing was hooked up. I just ran it back to the wiring panel and let it hang there.
- Once I passed the electrical inspection I hired a professional electrician to install my sub-panel and then "hook up" all of the wiring circuit to breakers in the sub-panel.
- Then I could turn off the individual circuits (the wires), wire the plug or light switch, then turn it back on to see if it worked. (after the drywall was installed)
Can I tell you something that is going to completely blow your mind?
Ready...?
You can wire your basement and pass your electrical inspection without ever turning on the power.
BOOM! Say what?
How does the inspector know you wired your basement correctly? They just need to see that it was wired correctly. If you did it right, you can move-on to drywall. They'll check light switches and plugs in the final inspection.
Listen, hopefully this article gets you going in the right direction. You'll still have to read a couple of books and spend a few weekend wrapping your brain around the basics concepts of electricity. But once you get that part down you are golden.
It's Just Wire
We'll need another article to cover how to run electrical wire. Plus, I want to cover the type of things that inspectors are want to see. For now, remember these 2 things:
- You can run your own electrical and pass inspection without ever turning on a light or hooking up a plug.
- Finishing your basement requires three types of wire. 14/2 (lights), 14/3 (lights with 2 switches) and 12/2 (plugs).
If you're going to your local Home Depot or some other hardware store this may be your first time in the electrical section. Don't freak out.
There's a lot of stuff that you've never seen. Just remember what you need - 14/2 - White, 12/2 - Yellow, 14/3 - White. If you want to start small get a 100 feet. But if your basement is a thousand square feet or more you should go ahead and buy the 250 ft roll.
Some people may call it Romex. Romex is the Trademarked BRAND name of Type NM cable invented by the Rome Wire Company. That's what we've been talking about.
Good luck on your project. I hope you'll consider trying electrical (if your area allows it), it's really fun and you can do it!
Cheers - Jason
Need More? Check out These Other Resources
1. Go back to how to wire a basement main page
2. Do you need some electrical books? Here's what I used.
3. The history and origin of Romex Wire (don't pick this, so boring)
WARNING: You are responsible for your own safety and that of those around you. This article is my opinion. I am not a licensed electrician. You should consult with your municipal building department to see if you are allowed to work with electricity without a license. ifinishedmybasement.com cannot be held liable for injuries or damages.
Did you have a professional install the sub panel and then you yourself wire and install the breakers into the sub panel as you went along? Or did you completely wire your basement with dozens of wires dangling where the sub panel would go and then have the professional install the sub panel, and wire and install the breakers?
Good question - I had a professional install the sub-panel and hook up the 5 or 6 circuits that I had already run. However, when I added my bathroom GFI a month or so later - I was able to turn of the power to the sub-panel and then fairly easily install my own circuit breaker and wire it up. I do not recommend installing your own sub-panel.
I'd be very careful. Most jurisdictions are not going to give you a final without the power turned on. Splices and torque are key. I don't practice dentistry, amateurs shouldn't practice electricity.
Good point, Kenny! Doing household electrical work is VERY similar to dentistry! And no one should learn to do anything for themselves - they should probably overpay a master electrician to do even the simplest of things! Such BS.
Good introductory article, and I'm sure many DIYers can use your advice and info to save some decent money by avoiding the shysters out there comparing their household electrical work to medicine. Make sure you own and know how to use a voltage tester before working on any existing circuits, get a polarity and ground tester for outlets, and if/when the time comes to hire an electrician, insist on written quotes with materials and labor itemized.
If after reading this great post you are not 100% sure how to do the wiring, hire me
Excellent info. Thanks Jason
I need to pigtail my ground and neutral wires to connect to my new leviton decora smart light switch. what do I ask at home depot to buy these pigtail ground and neutral wires?
what does it mean by NM-B wire or THHN? I don't know which one to buy for my light switch, and don't know the exact specs to ask for. thanks
Hi Fred - You won't find "pigtail" wire sections for sale at Home Depot because people tend to make them themselves. A pigtail is just a single wire (of the the three in a typical Romex wire strand - Black, White, Ground) You just cut out a small piece of wire and then use it to make a pigtail. If you don't have any extra wiring you could buy that at home depot - just buy the smallest amount they sell of NM-B wiring (often called "Romex" for short). Here's a link to what you need, looks like they might sell it by the foot. - Jason
I loved this site and it's easy explanations, but it may be wrong depending on the amperage of your branch circuits. So, add to his advice 20A breaker = 12g wire, 15A breaker = 14g wire. You can use an oversized wire on a smaller capacity circuit (e.g. 12ga on 15A circuit), but not the other way around. If you don't follow this then the insulation could theoretically melt and short out and you will likely get cited for a code violation.
Thanks for the easy-to-understand explanation! Hey, so the Amazon link for the books you used is dead, can you post the book names by chance?
Hey Riaian - Here's a link to the 3rd edition of the electrical book I used.
Iam using steel studs. What type of boxes can I use.
The type of box doesn't matter, it depends on the type of wire. If it's non metallic sheathed wire, you can use either metal or pvc box. If it's metallic sheathed wiring, use metal boxes only. To install onto a metal stud, usually the box would have a plate on the side of it to screw it directly on the the face of the stud. If not, then you would simply screwed the side of the box to the side of the stud.
Please update your instructions. It is dangerous and incorrect to say that 14-2 is for lights and switches and 12-2 is for receptacles. The size of the wire has nothing to do with the device connected to it. It is all about amperage. If you are going to wire up a circuit with 14-2 wire, then it must have a 15A or smaller breaker feeding it. If you have a circuit with 12-2 wire, then it must have a 20A or smaller breaker feeding it. If you have a circuit with both 14-2 and 12-2 wire, then it must have a 15A or smaller breaker feeding it. The wire size is ONLY about amperage.
Curious as to why you he is using 12/2 on his outlets?
Lol, because he literally states that exactly. “12/2 - The Yellow Wire - used to wire plugs”. Where I am 14/2 is used very often for “plugs”, switched and lights...but ?.
There is a lot of good information here, thanks ?
I am going to wire my basement. I will have 2 bedrooms. But only 2 or 3 breakers in my panel. I plan on having a ceiling fan/light in middle of each room, a closet in each room w a switch and 1 light. 7 receptacle in each room and 6 cans in each room with a switch. Please tell me simplest way but correct way to run wire.