electrical question - porch addition

[toughguy]

I'm building a 3 season porch addition and I'm running electric to it. I had a bunch of 12 gauge wiring on hand so I ran that to the addition. I'm going to run 5 indoor outlets (TV, lamps, radio etc.) and 3 lights (ceiling fan and 2 exterior lights)and 1 exterior outlet out there. It's my understanding that I can run a 20 amp or 15 amp off 12 gauge wiring.

Should I just go with a 15 amp circuit? Are the items above too much for 15 amp?

If I go with 20 Amp - I know there are 20 amp outlets available. Do I need these if I go with 20 amp cct?

If I go with 20 Amp - Do I need 20 switches?

If I go with 20 Amp - Can standard lighting fixtures handle 20 amp?

I will be getting it inspected. Just want to pass the first trip out if I can lol

I know it's a long list of questions. I appreciate any feedback.

[JohnMickish]

If you put the 12 gage wire on 15 amp breaker, they you have to use 15 amp devices, but if you put it on a 20 amp breaker you can use either 15 or 20 amp devices. There is an exception in the code book that allows you to do that. The breaker is the key here, not the size of the wire.

That is not to much stuff for a 15 am breaker.

[toughguy]

Thanks. I think I'll just go with a 15 amp cct

[LightningBG]

If you put the 12 gage wire on 15 amp breaker, they you have to use 15 amp devices, but if you put it on a 20 amp breaker you can use either 15 or 20 amp devices. There is an exception in the code book that allows you to do that. The breaker is the key here, not the size of the wire.

Are you sure you dont have your wording backwards?

Are you saying you can put a 15 amp outlet on a 20 amp wire/breaker?

I think you mean you can put a 20 amp outlet on a 15 amp breaker/wire.

If you run a 20 amp breaker, with 12ga wire (20 amp), and a 15 amp outlet, you run the risk of melting down the outlet.

[JohnMickish]

No, I have it right. There is an exception in the NEC that will allow you to put 15 amp receptacles on a 20 amp circuit. I'll bet money that your house has plenty of them in it. A 15 amp receptacle has two vertical slots for the plug in, a 20 amp receptacle has two vertical slots, but the grounded conductor slot also is made for a horizontal prong to fit.

A 15 amp plug in has two vertical tabs, a 20 amp plug has one vertical and one horizontal tab. Things are made this way so you can plug a 15 amp appliance into a 20 amp receptacle, but not plug a 20 amp appliance into a 15 amp receptacle.

Here is a list of NEMA receptacle configurations. If your kitchen and bathroom do not have the one that looks like 125v 20 amp, then you have 15 amp receptacles on 20 amp circuits.

[CAMAN]

Makes perfect sense to me! More than likely those 15amp outlets are made to handle 20+ amps anyway.

BTW...Is there anything made with the 20 amp plug? I've been in many industrial and commercial settings and have yet to see one.

[JohnMickish]

Yes, there are lots of tools that use a 20 amp receptacle. Core Drills, floor grinders, mechanical wire pullers (tuggers) are just a few that will easily trip 15 amp breakers. These are not the kind of tools that homeowners run down to Home Depot to pick up on sale for $100.

[SkunkedAgain]

I'm going to run 5 indoor outlets (TV, lamps, radio etc.) and 3 lights (ceiling fan and 2 exterior lights)and 1 exterior outlet out there.

You should be fine with a 15amp circuit but only you know how you plan to use it. The tv and lights won't put on much load but you may want to calculate out your theoretical load to determine if it's worth putting in the 20amp receptacles and breaker.

When I renovated my basement, I ran all 20amp just thinking ahead towards the future. I've got a beer fridge running on it, entertainment system, a bunch of overhead lights, feature lights on the bar, lots of outlets, etc. I hated the old system where the breaker could flip while friends were over to watch the big game.

The only issue about working with 20amp wire is that it's harder to bend and work with in tight spaces...not by much but it's noticeable.

[toughguy]

.

The only issue about working with 20amp wire is that it's harder to bend and work with in tight spaces...not by much but it's noticeable.

About the only good thing about working in this 90 degree heat is the wire is a little easier to bend than if it was 30.

I did some calculations and if I had my electric smoker, tv, radio, all lights and the fan on I'm getting close to, bot not over 12 amps. At this point I'm looking forward to getting everything done and watching a little football out there this fall.

[JohnMickish]

12 Gage sold just sucks. It doesn't matter if its hot or cold in those tiny residential boxes its a pain in the rear.

[SkunkedAgain]

I did some calculations and if I had my electric smoker, tv, radio, all lights and the fan on I'm getting close to, bot not over 12 amps. At this point I'm looking forward to getting everything done and watching a little football out there this fall.

Do you ever envision running a space heater out there when the fall football weather puts some nip in the air? That could definitely drive the amperage up higher

[toughguy]

I have a separate 20 amp cct for a 2000 watt baseboard heater. I hope to keep it open/heated through Christmas.

[cavalierowner]

I've been following this thread and I'm confused. If you already have the 12 ga. wire and you can use a 15A receptacle on a 20A circuit, why not just use a 20A breaker? As near as I could see online a 15A and 20A breaker are the same cost, under $5 assuming it's a residential panel. Then the extra capacity is always there if you need it in the future. Or is the 15A breaker already in the panel?

[Whoaru99]

I agree with the last poster.

If you're already decided on using the 12ga wire I don't see any reason to use a 15A breaker instead of a 20A breaker. Afaik a 20A is same price as a 15A breaker and all the rest of the stuff can be the same (15A receptacles, switches, etc).

Also, if you have room in the (main or sub) panel, I'd be tempted to put any permanent lights on a separate circuit. That way, on the slim chance the breaker on the receptacles would ever trip, you still have lights.

[LightningBG]

No, I have it right.

Yes, you are correct. Just doesn't seem correct. My mistake.

When you say "devices", does that mean switches and lights too?

Lets say running a standard ceiling fixture, tapped off of a 20 amp outlet (20 amp breaker)(non kitchen or bathroom). Can a 15 amp switch be used? Would you have to run 12 ga between all?

I've never done this, just curious.

[JohnMickish]

From an electrician's point of view, you are best using the proper sized breaker according to wire size. The reason for this and someday someone else may have to go into the system and open up a box and see the wire and assume the circuit rating. We all know what happens when you assume something.

[Whoaru99]

Yes, you are correct. Just doesn't seem correct. My mistake.

When you say "devices", does that mean switches and lights too?

Lets say running a standard ceiling fixture, tapped off of a 20 amp outlet (20 amp breaker)(non kitchen or bathroom). Can a 15 amp switch be used? Would you have to run 12 ga between all?

I've never done this, just curious.

You would have to run 12ga between all the points, breaker, switches, receptacles, etc.

With regard to switches, the stipulation is they must be used within their rated capacity. So, you could have a 15A switch running quite a few ceiling fixtures (depending on wattage, of course) before there was any concern with upsizing the switch. As far as the fixtures themselves, 12ga to the box if you're using 20A breaker, but certainly individual lighting fixtures typically do have smaller gauge wires that tie/connect to the 12ga branch circuit within the box.

[toughguy]

I have to have the rough in inspection next week. I have a bunch of 15 amp outlets and switches on hand already. If he says he'll pass 20 amp over the 15 amp outlets/switches I'll go that route but if he recommends 15 I'll do that. Just want to make the inspections go smoothly.

I know yellow wire will make you think 20 amp when you go to the breaker box but if it's clearly labeled "porch lights and outlets" I doubt someone would flip the one marked "kitchen" just because it's a 20 amp and expect the porch power to be cut. Anyone that just randomly picks a breaker and guesses that the power is out without testing it deserves to be shocked anyways. I've done that in the past and I deserved the jolt lol. That'll wake you up quicker than 8 cups of coffee.

[Whoaru99]

I didn't mean accidentally switching off the wrong breaker, I meant separate lighting circuit so if something plugged into the receptacle circuit trips the breaker due to overload/malfunction, you don't lose the room lights too.

Also, using a 20A breaker on 12ga wire with 15A receptacles and the typical home wiring switches and such is absolutely allowed by NEC. The only exception to putting a 15A receptacle on a 20A circuit is that you can't have just one, single 15A receptacle on a 20A circuit. A single 15A duplex receptacle counts as two so as long as you have at least one 15A duplex receptacle or at least two 15A single receptacles it's OK by Code to connect them on 12ga wire with 20A breaker.

[Whoaru99]

Also, I think receptacles have to be installed every so many feet of wall these days, and can get a little tricky when you have short spaces, say like maybe between a doorway and adjacent wall.

Haven't checked the specifics for a while, but I think it's like a receptacle on any wall that is 24" or more wide, then (at least ?) every 6 feet.

Did you factor your receptacle count and spacing with this in mind?

Also, I think AFCI breakers may be required on new circuits.

[toughguy]

Haven't checked the specifics for a while, but I think it's like a receptacle on any wall that is 24" or more wide, then (at least ?) every 6 feet.

Did you factor your receptacle count and spacing with this in mind?

I just saw something on that the other day. I think I have to add one more outlet. It's going to be behind a couch and the current gap is about 8' but I'll toss in another one just to be safe. Thanks for the heads up. Lots of good info here. The code is getting so detailed/complex it's hard to follow.

[JohnMickish]

They have to be no further than 6' from any point on the wall, or in laymans terms, 12' apart. What is and what isn't considered wall space is pretty clearly spelled out in the code book, but I don't remember some of the rules. I know that sliding glass doors come into play, but can't remember if you count it or not.

[Whoaru99]

Yeah, six feet from any point makes sense rather than six feet apart, since that's roughly the length of the cord on lights, TVs, etc. Should be able to get to a receptacle in most situations without using an extension cord that way.

Like with a lot of Code, I presume that is the minimum requirement and that one could close the gap more, if they wanted?

[toughguy]

If I have a sliding door on one wall, 4 feet of wall, a corner, then a 3' door about 6" off that next wall do I need an outlet in between the doors? If I counted the doors there would be 14' of gap between outlets but there's a good 9-10 feet of doors in that 14 feet. I can post a pic when I get home if that helps. The 3 foot door swings open into the 4 ft of open wall space where the outlet might be needed so I won't ever put anything there (it would block the door)

[cavalierowner]

In my non-expert understanding of the code, you will probably need one there. Heck, plug in the vacuum cleaner there. FWIW, I don't think you can have too many outlets; they're dirt cheap in comparison with the rest of the project.