10 gauge

 

12 gauge is for 20 amps

10 gauge is for 30 amps.

You have a 30 amp receptacle and breaker, so you need 10 gauge.

 

Not always Kevin. What if the op is installing only an AC out in the garage. What if he is not Canadian. That would mean he possibly could use #12 to run a 30 amp circuit providing the ac has a hermetically sealed compressor with overcurrent protective clicks'on devices built in. Nec 440 covers that.

Say Kev, does this place tell you Canadian/ not Canadian before you answer a thread? How am I supposed to know ? What is your method to figure that out Kevin?

 

Ok makes sense .. not sure why I couldn't figure that out in searching. I think I may have been confusing the research I did on 20A vs 30A circuit, because originally I was looking to just install a 20A.

10/2 it is, thanks gentleman!

 

10 gauge is for 30amps regardless of whether it's 120v or 240v.
But, some 240v wired appliances or devices only need three wires, while others need four.

As long as the amperage for the appliance or devices is 19amps, you'll be no where near the 30amp maximum, so the 10gauge is certainly even 'more' than you need, but certainly correct for a 240v 30amp connection.

I have one of these for my son's Electric Vehicle Charger, 240v 30amp, 3 - wire, with no Neutral, as both 'sides' are pulling the same amps at the same rate.

I also have a 240v 50amp Motorhome, but that's a similar, but different, 4 - wire 240v scheme since both 'sides' don't always pull the same amperage, needing the Neutral wire to balance the load.

Your appliance instructions will tell you whether the 3 - wire or the 4 - wire is what it needs.

 

Thanks for that additional info, NCmountainCabin. You've got me wondering if I should run 10/3 instead of 10/2, or would that not be possible or advisable? I'm getting out of my level of electrical knowledge here, but thinking if 10/3 could handle the same scenario I currently need (heating element calls for three wires, L6-30 outlet) but then I would have that extra wire 'stashed away' in case someone down the line needs it...

I'm thinking that might not be possible?

 

Actually I guess it would be possible, and I could just leave one of the hot wires disconnected on both ends. But again I defer to you all

 

DAMN....

Just so there is no nomenclature confusion.....10/2 with ground= (3 wires) 10/3 with ground =(4 wires).

You probably are aware... but just to maker sure....

Is your garage attached (makes a difference.)

If attached....do you have other electrical circuits out there or will you want (now or in the future) more 120 circuits.

If the garage is detached, we have different questions/considerations.

This will help anyone as to advising you on the best install for your uses.

 

Thanks MTN REMODEL LLC. I had learned previously about the (confusing at first) 10/2 having 3 wires and 10/3 having 4 (i.e. ground wires). Probably learned of that from one of the fine folks on this forum

Garage is attached. It's got plenty of 120V outlets out there. I just have a new need for this 240V, 30A circuit.

Based on others info I plan to run the 10GA. I'm assuming I can run 10/3 and just leave the red wire disconnected at both ends (in case it's needed in the future for something else in the garage). I figure there's no harm in it if it's disconnected, but just wanted to double check that. Otherwise I'll just use 10/2.

Thanks!

 

Considering you're hooking up a 240 volt load, if you run 10/3, you'd cap the white. Use the red and black for the conductors that connects to the receptacle and breaker.

If you run normal 10/2, tape or paint the white wire red (i don't know what NEC says, but my Ontario Electrical Code says I can, so I'm telling you to...)

You can also buy 10/2 that has a black and red rather than black and white.... this is preferred.

 

Ah thanks Kevin_Essiambre, that makes sense about using the red & black, instead of black & white. So I can go with 10/3. Connect red to one pole of the breaker, black to the other, ground to the ground bar, and cap the white wire since I don't need a neutral.

 

Connect the red and black to the breaker and the white to the neutral bar in the panel. Cap the white off in the receptacle box and connect the red and black to the receptacle line terminals and the green wire to the box and the ground terminal on the receptacle.

Current code requires GFCI protection on that receptacle.

 

Eeek... that GFCI breaker is expensive compared to $10 (like 10x more expensive). I was just looking at the GFCIs and thinking 'glad I don't need that' and then you came in here and burst my bubble. But now that I think about it, it's probably best for safety. I have little ones running around, and the application I have in mind will have this circuit occasionally in use for hours on end.

Anyone got any spare 30A GFCI double poles laying around to share? lol

I have wired one of those GFCI breakers before, but it's been a while. Will need to refresh myself on the youtube.

Thanks!

 

Thanks surferdude. Ok after diving in a bit on youtube, I think I need to look back in the panel and see what kind of setup I've got. It seems like where I should be connecting the GFCI breaker pigtail can vary (i.e. ground bar, neutral bar, or they could be the same) based on how it's wired to the grounding electrode in my particular setup. I'll check the panel out tomorrow. I assume it will be easy to tell, either all grounds on one bar and neutrals on another, or a hodge podge.

I'm with you on the rest of the connections ... but I didn't understand this part:

connect the green wire to the box and the ground terminal on the receptacle

Are you saying connect the ground going to the receptacle to both the gang box AND the receptacle ground terminal? I thought it would just connect directly to the receptacle only (along with the two hot wires doing the same).

 

The GFCI pigtail connects to the neutral bar.

Since your 30 amp receptacle is a grounding type but not "self grounding", you must connect the ground wire to the ground terminal on it.

Furthermore, code always requires a metallic box to be grounded.

So yes, ground them both. I always loop the ground wire from the panel directly around the ground screw in box and let it extend on another 6 ~ 8 inches for a pigtail to serve the receptacle or other grounds passing through, if there are any. That way with a box that has other downstream connections, it's always easy to tell which run is the home run (feed), well, for me anyway and looking at my old work.

 

If your grounds and neutrals are commingled in your panel, it indicates that it's a "main panel" as opposed to a sub-panel. That's allowed but I never do it. In that situation, you can connect the GFCI pigtail on either connection bar you like.

 

Got it. Yes this is a main panel, don't have any subs.

I was going to just use a plastic old work box (this receptacle will be in the wall). Face plate would be metal just for durability/protection since its in the garage. Should they both be metallic in order to ground them both, or would the plastic old work box (ungrounded) with metal face plate be ok?

This will just be a single receptacle circuit feeding this 30A, no plans to branch off (but will be leaving some slack in the romex behind it, in case that changes in the future).

 

You get to choose... either type box is allowed for residential and the metal plate is fine on either one.

 

And yes, the GFCI 2 poles are expensive. That's why many people choose to direct wire certain things to avoid having to use them. Then all you need is a simple disconnect switch that's accessible at or withing view of the device (50').

 

Yes I respect all of that, and the same thoughts (or well close enough) ran through my mind. However I have a 2 year old and another on the way. I'm making a DIY steam sterilizer barrel (i.e. 55 gallon barrel full of water with 240V going into it) and plan to run this contraption just under the awning. God forbid it rains, or floods, and I forget I have the thing on, and some mishap happens where the electrical contacts a pool of water, which then contacts my daughter. Chances of such a series of events happening are close to nil, but I don't want to one day say 'I wish I would have spent the extra $90 on a GFCI breaker'. I don't do this type of thing often, so when I do I err on the side of caution. Peace of mind if nothing else.

 

For anyone curious (or concerned lol) this is a mushroom substrate sterilizer that will run at atmospheric pressure (i.e. not pressurized) but will have pressure relief valves just in case. I'll be using a 4500W heating element, and a steel ball valve to ensure the water never runs out. Basically a DIY version of one of the Bubba's Barrel's that are popular for home brewing or whatever else. I'll have it wrapped with insulation, then some sort of makeshift wall around it so nobody gets too close. Most likely it will pipe the steam over to another barrel or barrels that will have the same safety mechanisms as needed. The main barrel will have a temperature PID controller and a timer to shut it off after a TBD cycle time.

I think with you guys help I just about have the necessary electrical needs for this project all worked out. I'll post back if I hit any new questions when I'm actually running the new circuit ... thanks guys!

 

Please cite this in the NEC.

As far as I know a ground wire in a metal conduit is only required in the NEC for swimming pool equipment/pump motors. Else where a properly bonded metal conduit is perfectly fine.

 

Take bickering off site.


https://www.diychatroom.com/f114/diy-chatroom-community-rules-281002/





2. Users shall treat each other with respect at all times on DIY Chatroom.com. Ideas and opinions may be challenged, but name calling, personal attacks, or other inappropriate behavior will not be allowed and may cause your account to be banned. Harassment will not be tolerated in this community. This includes private messages, Avatars, Facebook and/or social media and user emails.

 

https://www.diychatroom.com/f114/diy-chatroom-community-rules-281002/



2a. Users shall not question or debate a moderator decision publicly on the message board. In the event of a disagreement or questioning of a moderator's decision or action users should contact the moderator(s) or admin(s) via PM.

 

Here is "UF" cable, it is in fact, gray . When talking to a DIY person. they need to know what they are to look for at the Home Depot. the Wire is Dark gray. It can be buried right into the dirt, 2 feet deep. But it has to have some sort of sheathing or sleeve when coming up from the ground, and when you go into the ground

Like a pvc. the one found in the electrical department
Is is that same color gray. So yes... gray.
so easy to install. Even big Bird could install it.

I prefer pipe.
but I dont make claims
Hope this helps people

https://sutherlands.com/products/images/20305/7205479_ep_1412088198.jpg

 

If you are really worried. Install new 30a GFCI breaker in the house. Run 2" GRC conduit to the garage with #4 UF-B cable inside for protection and voltage drop on the 30' run. Pull an extra #6 SOLID ground wire(Just in case) and then use a minimum 2" concrete to encase the conduit. Make sure the trench is at least 24" deep to allow for vehicular traffic (mowers and such). This should be safe.

EDIT: don't forget to call 811 for dig alert.

 

Well boys, I have met my match. This damn conduit, or whatever it is, is FULL of wiring for the rest of the house. I was barely able to get just my fish tape up the conduit and into the attic, taped the new 10/3 to it, and got it about half way down the pipe (to the white/grey line or so), at which point an epic struggle ensued over about half an hour before the tape busted and I pulled an empty fish line out the bottom. I even tried lubing the 10/3 up with Vaseline, which helped a little but not enough. Now here I sit, broken, beaten and itchy, with no clue how to get this wiring all the way down.

Any ideas? I did take the cap off the CANTEX box thing, which is how I was able to get the fish tape up there, but that's about the only thing I found that helped.