Calling Electricians - adding a 20-amp circuit in garage

[MichaelD]

CLIFFS
1. Want to add 20-amp circuit/outlets in garage
2. There is an existing 15-amp GFCI outlet but the breaker trips due to too many tools
3. Service panel is in the garage, 20 feet from where I want the outlet
4. Licensed electrical company quoted $500 for job
5. I call BS and want to do it myself

BACK STORY

I want to add a 20-amp circuit/outlets in my garage b/c there's only one existing 15-amp GFCI outlet in the garage (which is gang-wired with a few other outlets inside the house), and the associated breaker trips when I try to run the table saw and dust collector.

Not looking for fancy. I want a simple, surface mount outlet box with the standard shiny metal conduit running from it to the breaker box. Said breaker box is also located in the garage, about 20 feet from where I want the outlet.

I contacted a local licensed/bonded electric contractor and they quoted me $500 for the job. This is a new house (6 years old), BTW. This job requires about $60 in supplies; everyone knows this.

I can do the job myself, but want to do it "to code." I looked at the NEC on the www.nfpa.org website, but I can't make heads or tails of it.

I have changed outlets, installed dimmers, ceiling fans etc before, safely (appropriate gauge wire, grounding etc) but never done something like this before.

Would someone please tell me how to wire a 20-amp breaker into the box and run the wire?

 

[edro]

1. Add a new 20A circuit breaker to the panel
2. Run the 12ga Romex through your conduit
3. Attach the conduit to the distribution panel and to the wall
4. Add single gang box to conduit and attach to wall
5. Connecting wiring to breaker and new GFCI outlet
6. Profit

You can google images of how to do this. It is really simple and will cost you less than $50 in materials.

 

[MichaelD]

Thanks, erdo. So, you just clip the breaker into the panel? The distro panel is inset into the wall (sheetrock). I guess I'd have to break into the sheetrock then.

What about changing the breaker for the existing outlet to 20-amp? That would assume the wiring from there to the outlet is 12ga, correct? I bet it's not, though. And I am smart enough to know that the breaker protects the wiring, not the devices. I.E. 20 amps through 16 or 14ga wire will create a heating element. Not good.

I want to do the job so it looks like it was done professionally. I can run wire...I even own fish tape. But what about connecting the conduit to the breaker box? It's recessed into the sheetrock.

 

[Analog]

If its that close, just buy a 20A GFCI breaker and use a standard outlet.

 

[MichaelD]

If its that close, just buy a 20A GFCI breaker and use a standard outlet.

What about the wiring in the wall? If it's not the appropriate gauge it could cause a fire.

 

[edro]

See what gauge the wire is on the 15A outlet. Take the cover off and see if you can read enough of the wording on the jacket, or hold a 12GA wire up to it and see if its the same size.

If your breaker box conduit entries aren't accessible, you will probably have to cut a big section of drywall out and next to it. You could cut a 20ft long strip all the way down and drill through the studs and run your wire that way, then repair the drywall.

Or, you could run the metal conduit on the outside of the drywall and they go into the drywall right next to the box.

Take a picture for us and we'll walk you through your options.

 

[MichaelD]

Thanks again, erdo. I'll take a pic tonight when I'm home. Will probably go the "outlet next to the box" route. Don't need conduit and could run the wire in the wall w/fishtape. No drywall to repair that way (new outlet covers new hole). That $500 quote was just stupid. For $200 I might go for it, but $500? Really? :roll:

 

[Miramonti]

I did this myself for the first time and it's very easy. I didn't have to use any sort of conduit just this, sending it thru the wall from the attic and down to the box in the garage. I replaced 15a gfci's with 20a breakers and added a few breakers. Gfci's tripped way too easily, couldn't run treadmill and other stuff.

 

[skyking]

If that circuit goes off into the house to other outlets/lights, best to leave it alone. You'd have to chase it all the way through to be sure you were not 20 amping a 14 ga. wire somewhere, plus you are still sharing a circuit.
put in a dedicated circuit with a gfci outlet, and wire any additional outlets off of that.
do not install a gfci breaker unless you are carved out of money. They are easily twice the price of a conventional breaker plus a gfci outlet.
You may be up against a motor problem that will pop any gfci, I have seen that before.

 

[Fausto]

No clue, I'm just here to say I hope you don't electrocute yourself and if you do, make sure it's uploaded to youtube.

 

[Analog]

What about the wiring in the wall? If it's not the appropriate gauge it could cause a fire.

You'll still have to run 12AWG romex, it'll just then go to a standard outlet.

 

[Linflas]

1. Add a new 20A circuit breaker to the panel
2. Run the 12ga Romex through your conduit
3. Attach the conduit to the distribution panel and to the wall
4. Add single gang box to conduit and attach to wall
5. Connecting wiring to breaker and new GFCI outlet
6. Profit

You can google images of how to do this. It is really simple and will cost you less than $50 in materials.

When I did a couple at my house with my brother who is an electrician the only difference from the above was that he ran the wire first, attached it to the outlet and the box 2nd, and at the end snapped in the breaker to the panel. Also make sure to make note of the make and type panel before going to buy the breaker, there are several different makes and types. Also current code according to him is to install the outlet with the ground plugs at the top rather than at the bottom.

 

[MichaelD]

Thanks very much, everyone. I'm going to go the dedicated outlet route. Instead of breaking the sheetrock to run conduit into the breaker box for a surface-mount box near my tools, I'll just put a dedicated outlet 12-24 inches from the box and run a 12-ga extension cord to my tools. One plastic outlet box, one 20-amp GFCI outlet, one 20-amp breaker and about 6 feet of 12ga Romex and that's that.

However: I need to look at my distribution panel tonight; I can't remember if it has any open slots left. If it doesn't, then I'm SOL.

 

[skyking]

Michael ,you can swap in a *tandem* breaker in many cases and get another circuit in.
http://www.ehow.com/how_8524370_install-basic-doublepole-circuit-breaker.html
Those 4 little red handles on the left side are doubles. They are not 220 circuits, just two breakers in a narrow format that fit into one slot.

*Edited to correct terminology

 

[Rubycon]

That article is wrong. A double pole breaker is for 240VAC loads. A breaker that fits in a single slot for a pair of 120V loads is called a tandem breaker.

Take a picture of your panel and post it.

 

[edro]

Also current code according to him is to install the outlet with the ground plugs at the top rather than at the bottom.

LOL, must be local code because the NEC has said you can orient either way and it has always been a hotly debated topic.
Supposedly the original intention was ground post up, but it's not required in NEC.

 

[skyking]

I was not quoting the article, just using the picture and the wrong terminology. Forgive me!

 

[Rubycon]

LOL, must be local code because the NEC has said you can orient either way and it has always been a hotly debated topic.
Supposedly the original intention was ground post up, but it's not required in NEC.

Some feel ground up is safer in case something conductive falls (like one of those spring steel signs they hang up on foreclosure sales) and makes it way between the plug and outlet face the grounded prong will prevent it from touching across hot and neutral blades. Of course circuit breakers - when properly working and of good quality (no Federal Pacific NoTrip junk from the 70s please) - spring into action and disconnect the load promptly. Think Square D QO series.

I was not quoting the article, just using the picture and the wrong terminology. Forgive me!

Haha no problem, these articles spring up all the time with these mistakes. Sad thing is I'm no electrician and see it like a sore thumb. :$

 

[MichaelD]

Thanks very much everyone. I'm pretty sure on what I need to do.

1. Determine if I have any empty slots in the panel...if not, program ends here.
2. If we got past #1, determine what brand panel I have/breaker I need.
3. Buy supplies (12ga Romex, Romex grommet, 20 amp breaker, 20 amp GFCI outlet, plastic wall box)
3. Cut hole in sheetrock, mount box, install Romex grommet in box, run wire, wire outlet, connect wires to breaker, neutral and ground, snap breaker into panel
4. ???
5. Profit!

Sound right? I looked at videos online and understand the diff b/t a 220 and a 110 breaker. Two slots for 220 on the bus-connection side vs. one slot for 110.

 

[Rubycon]

You don't need a grommet or clamp if using a plastic box and NM-B wire.*
Where the wire leaves the panel you need a cable clamp. 3/8" should work for 12/2 NM-B just fine. Don't forget a 20A receptacle. The left slot will be T shaped.

________________

* ALWAYS consult with LOCAL codes to find out EXACTLY what it required!

 

[MichaelD]

Thanks very much, Ruby. I'm going to take a look at how the other breakers are wired (grommets and such) and duplicate it. I wish I was home now...wanna get started on this!

 

[geecee]

Not to hijack your thread MichaelD, but I have a stupid question, as I know nothing about electricity. If you have a tool or appliance that draws 15A, and you plug it in a standard 15A socket, are you asking to blow a fuse or trip a circuit breaker?

 

[MichaelD]

Not to hijack your thread MichaelD, but I have a stupid question, as I know nothing about electricity. If you have a tool or appliance that draws 15A, and you plug it in a standard 15A socket, are you asking to blow a fuse or trip a circuit breaker?

Yes. The breaker or fuse is there to protect the wire in the wall. You have used a toaster, right? The metal strips that glow red inside are heating elements. Similarly, the wires in the wall of your house will also glow red if you pass too much current through them. The breaker is there to prevent that from happening.

Normal outlets in your house are 110v/15-amp. The wire that attaches the outlets to the main fuse box are sized appropriately (typically 14-gauge). The outlet for your stove or electric dryer is different b/c it handles a higher voltage and much more current. The wires that connect those outlets to the breaker panel are much thicker (12 or 10 gauge) and the breaker is sized accordingingly.

 

[geecee]

Thanks for the answer. What about something say under that amount, i.e. 12-13A. Will it occasionally draw more, and blow the fuse/trip the breaker as well? Or will that be ok in the socket?

 

[Rubycon]

Yes. The breaker or fuse is there to protect the wire in the wall. You have used a toaster, right? The metal strips that glow red inside are heating elements. Similarly, the wires in the wall of your house will also glow red if you pass too much current through them. The breaker is there to prevent that from happening.

Normal outlets in your house are 110v/15-amp. The wire that attaches the outlets to the main fuse box are sized appropriately (typically 14-gauge). The outlet for your stove or electric dryer is different b/c it handles a higher voltage and much more current. The wires that connect those outlets to the breaker panel are much thicker (12 or 10 gauge) and the breaker is sized accordingingly.

Lots of smoke!

http://www.youtube.com/watch?v=T8GiuM-gABY&

Romexsmoke! Don't breathe this! :biggrin: