Latest Discussions : Electrical & Lighting


03:12AM | 07/15/03
Member Since: 07/14/03
1 lifetime posts
OK, I've asked a couple of electricians this question with very hazy answers. I think I understand the purpose of a 20 AMP circuit (like going to a kitchen) with 12 Gage wiring going to multiple 15 AMP rated outlets. In theory, it's unlikely that all the appliances plugged into different outlets will exceed 20 AMPS demand if all were started simultaneously.

Now, on such a circuit, why do you almost always see in residential homes only 15 AMP rated outlets installed? Wouldn't it be dangerous to plug something into to one of these outlets that requires, say, 16 AMPS at start up? Why are not 20 AMP rated outlets required for 20 AMP circuits?


08:26AM | 07/15/03
Member Since: 02/13/03
90 lifetime posts
My understanding is none of the individual appliances would typically draw more than 15 amps. But running two 8 amp appliances would blow your breaker if it were 15 amp and your wiring would get hot if it were only rated for 15 amps.

You'd want a 20 amp outlet if a single device were going to draw more than 15 amps and less than 20. Thou for short durations the 15 amp outlet would work, it does in everybody's house!

I have a 110v 20 amp wire welder in my garage. I wanted versatility in where I used it so I put heavy 20 amp rated outlets in everywhere. Could I get by with 15's, probably, but any lengthy welding project could heat up the 15 amp components quickly.


11:14AM | 07/15/03
Member Since: 12/01/02
93 lifetime posts
Here is a follow-up question... Suppose I am building a new house or putting in an addition, aside from cost is there any reason _not_ to put in 20 AMP circuits instead of 15 AMP circuits?

Tom O

01:20PM | 07/15/03
Member Since: 09/17/02
476 lifetime posts
Drawbacks of #12 are pretty much limited to box fill. It is easy to end up with too many conductors in a box if you use #12 wire.



04:39PM | 07/15/03
Member Since: 09/17/02
524 lifetime posts
The reasoning for 15/20 amp receptacles on 15/20 circuits is this. 15a and 20a receptacles have different pin configurations. A 20a receptacle will have one slot that is turned sideways or T shaped to allow a 20amp plug to be used.
A 15amp receptacle on a 20 amp circuit will not overload the circuit. You will only be allowed to plug in 15a devices. How many you plug in is always a concern that you should observe.
However if you put a 20 amp receptacle on a 15 amp it allows a 20 amp device(like an AC) to be plugged into a 15a rated circuit. This is an immedeate problem for the circuit.

[This message has been edited by joed (edited July 15, 2003).]


10:38AM | 09/13/13
If I currently have a 15amp outlet and a 20 amp plug in cord, Is it okay to just change out the 15 amp cover to handle the 20 amp plug in?


08:42PM | 03/16/14
Putting in a small room for central vac and freezer plus storage. Both require 20 amps. Can I just wire whole room for 20 amps?


02:33PM | 08/24/14
Yes it is easy to run all 20 amp circuits. Only a bad electrician would stuff the boxes with to many feeds to fit in a standard box. Run all 20 amp wire and plugs. (because your only talking about outlets)Its only going to cost more in materials.20 amp outlets and 12/2 is always better.


09:01AM | 11/11/14
My microwave is plugged in a 15 a outlet, don't know what happened but the outlet some how shorted out , microwave was not damaged, I tested it on a different outlet and works fine, when I replaced the outlet with an 20 a outlet thinking this will prevent the outlet from over heating, the circuit is still 15 a, is this ok


11:02AM | 11/12/14
Member Since: 11/12/14
1 lifetime posts

My microwave is plugged in a 15 amp outlet, don't know what happened, but the outlet some how shorted out , microwave was not damaged, I tested it on a different outlet and works fine,, I replaced the outlet with an 20 amp outlet thinking this will prevent the outlet from over heating, the circuit is still 15 amp, is this ok.??


12:58PM | 12/10/14
I would think it's okay as long as someone doesn't plug something that truly requires over 15 amps. Maybe mark the outlet with some text that says 15 amp? That's what I would do.


05:39PM | 12/12/14
I would check the wire and breaker and see what size it is. If the breaker is 20 amp and the wire is 12 AWG then it's OK. If it's a 15 amp breaker and the wire is 14 then go back to a 15 amp receptacle.


08:53PM | 04/13/15
i just replaced all my 2 prong outlets in my sons room with new 20 amp , i have no ground wire to attach to the new one the only reason i used 20amp is cause thats what my wife came home with is it safe having no ground and using 20 amp in a bedroom?


06:05AM | 04/14/15
Not safe and also a code violation.


10:51PM | 04/23/15
Older homes usually have no ground. No code violation. Unless you want to run new wire


04:56PM | 05/13/15
If the house is old and the outlets have no ground. You would be wise to use a ground-fault circuit interrupter(GFCI)outlet. See the following link It's an added level of safety (since the outlet is not grounded) so that you or one of your family members don't become the ground by accident


10:46AM | 09/30/15
I second replacing ungrounded receptacles with GFI receptacles if a ground cannot be achieved from the device box. This is what we do in DC regularly. To be up to code, the GFI has to be labeled with "No Ground." Also, a GFI tester will not work properly on a GFI with no ground.


07:46PM | 01/04/16
If I have a 15 amp breaker, can I install 20 amp outlets?


11:53PM | 01/07/16
> If I have a 15 amp breaker, can I install 20 amp outlets?

No! 20 amp outlets have a special pin configuration which allows a device drawing 20 amps to be plugged in. This would, at the very least, trip the 15 amp breaker. At worst, it could be a fire hazard. It is also a code violation.


10:23AM | 01/15/18
If you don't plug anything that requires over 15 amp draw, you're fine. The newer appliances that draw over 20 amps have a different style plug apparently. Keep in mind that you probably have 14/3 gauge for that receptacle, that's only rated for 15 amps. In the kitchen, the receptacles should be wired with two circuits, able to provide 15 amps on each side of receptacle, although I heard that they're wiring with 12/3 in newer homes now to provide 20 amp service, not sure about that, I'm not an electrician but know a bit.

To use 20 amps, you need to be wired with 12 gauge, the same gauge wire that is used for baseboard heaters, hot water tanks.


11:06PM | 03/21/18
1: you can't plug devices that pull more than 15 amps into a 15 amp reciprocal without nodding the cord, 20 amp outlets have a notch on the neutral side to prevent this. This is how you identify 15 and 20 amp receptacles.
2: NO. Do NOT replace 15 amp receptacles with 20 unless you replace the breaker with a 20 amp breaker AND *ALL* connected wiring from that breaker is 12awg or larger (larger size, not number. 14awg is not rated for 20amps). While you may not exceed the amperage, you will be violating code, and if it does mess up, you'll burn the wire before the breaker trips. Not the place you want the weakest link.


10:51AM | 06/10/18
Member Since: 06/10/18
2 lifetime posts
Goodness! The misinformation on this thread is staggering!

The 20A receptacle outlet has the special neutral configuration, like a cross. This identifies it as a 20A outlet.
Per the National Electrical Code, you may use a 20A receptacle outlet on only a DEDICATED 20A circuit. Meaning, when you see or use a 20A receptacle, it is supposed to be telling you that NO OTHER OUTLETS exist on that particular circuit; there is only the wire home run to the panel and it's own 20A breaker such as a washing machine circuit.

On a 15A circuit, per the NEC, you may NOT use a 20A rated receptacle.

On a 20A circuit, you MAY use 15A rated receptacles, or 20A IF it is a dedicated 20A circuit and outlet (no other outlets, meaning lights etc.)

So on a typical kitchen counter 20A circuit with say 4 receptacle outlets, you would have to use 15A rated receptacles. If only 1 outlet existed for a fixed appliance say a disposal or dishwasher, then use a dedicated 20A circuit with the 20A receptacle.


09:27AM | 07/28/19
I want to reiterate an earlier point, that this dedicated circuit needs a minimum of #12 AWG wire run to it, serviced by a 20 amp breaker.


09:55PM | 08/28/19
Great stuff! Thanks to all who have added input. One topic I didn’t see covered is the circuit breaker itself. I’ve been considering installing a 20A receptacle for an window ac unit but I’m a bit concerned that it’s more than just breaker, wire, and receptacle. Thanks to YouTube and this thread I am confident I can install but have 2 concerns I haven’t found much on:
1.) What type of 20A circuit breaker should be used and what are the pros and cons? I’ve seen a single and a double and even saw a 240V going into a double 15A I don’t understand how to choose.
2.) How do I know if my breaker box can take another added circuit and not encounter an overload issue ( i.e. my box can only put out so much at a time, right?)


08:17PM | 09/26/19
Should spot switch have same amp reading as breaker?


04:26PM | 09/28/19
Should amp of spit switch match Geico amp and amp at main breaker box?


04:29PM | 09/28/19
Should amp of switch match that of Ground fault and amp of breaker at main breaker box

coastal redwoods

05:05PM | 03/08/20
Member Since: 03/08/20
1 lifetime posts
If it is being said that only one 20 amp duplex outlet can be on any 20 amp circuit that must be dedicated, why do I see electrical how to books by Taunton Press, CodeCheck Electrical (Table 9), etc. showing multiple 20 amp outlets on a 20 amp circuit such as for two circuit layouts for kitchens


12:09AM | 03/10/20
>>If it is being said that only one 20 amp duplex outlet can be on any 20 amp circuit that must be dedicated, why do I see electrical how to books by Taunton Press, CodeCheck Electrical (Table 9), etc. showing multiple 20 amp outlets on a 20 amp circuit such as for two circuit layouts for kitchens <<

Because 20A outlet, the one with the cross hole, means "this is the only outlet on this circuit with a 20A breaker and a 12 gauge wire." The cross means dedicated outlet. It's a signal to people using the outlet. Appliances with a cord that needs the cross are for example some window air conditioners and they use too many amps alone that anything else on that circuit would blow the breaker. They need a dedicated outlet. The outlet itself doesn't have stronger contacts whether its a 15 or 20 amp. The weak spots on a 15 amp circuit are the wire and the breaker, not the outlet itself.

So if you put 3 outlets on a 20A circuit with a 12 gauge wire and 20 amp breaker, put regular 15 amp outlets on it. Then you can only plug in 2400W worth of appliances on all 3 outlets and turn them all on at the same time before the breaker trips.

If you have a 15 amp curcuit, with a 14 gauge wire and a 15a breaker, it can only handle 1800W before it trips.


08:39AM | 04/07/20
One other thing to remember, that I didn't see mentioned, is that sinking feeling you'll have when you discover your homeowners insurance wont cover the fire damage caused by non-compliant wiring modifications.


10:15PM | 04/26/20
Okay, there's some good info and bad info on the responses. One in particular stated that a 20A circuit can have a 20A receptacle only if on a DEDICATED circuit is incorrect. He needed to verify his code and provide evidence. NEC 2017, 210.21(B)(3): "Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Tabe 210.21(B)(3)..."

Then in Table 210.21(B)(3):

Circuit Rating(Amps) Receptacle Rating (Amps)
-------------------- ----------------------------
15 Not over 15
20 15 or 20
30 30
40 40 or 50
50 50

The 20A plug has a cross piece that will not allow a 20A device to plug into a 15A receptacle. So by its nature, Table 210.21(B)(3) is good without any issues if 15A receptacles are on a 20A circuit, especially since the maximum of 15A will never exceed the circuit rating. Though keep in mind that you're not supposed to exceed more than 80% of any circuit load with cord-and-plug connected equipment at any given time.

And he's also wrong about lighting only being on 15A circuits. It can be on 20A circuits, nothing in the NEC prohibits this. In fact, NEC 2017, 404.14(A) allows the use of a 15A switch (for resistive/inductive loads) on a 20A circuit as long as the total connected load does not exceed the rating of the switch. An exception to this is 404.14(F) which states that if the switch is controlling receptacles, then the switch has to be rated the same as the overcurrent protective device, i.e. 20A. There are plenty of 20A swtiches.


02:44PM | 09/07/20
Great info... but still considering myself a dumb and not sure if I understand everything thoroughly. My question: I have a 20a circuit connected to a 20a outlet, can i use it to connect a small window ac and another plug for desktop computer? Thanks!


02:46PM | 09/21/20
can i wire nut two 12ga and one 14 together?


02:49PM | 09/21/20
can i wire nut two 12ga and one 14 together?


10:12AM | 09/27/20
Electrician here. If it were my house, I would run all my outlets with 12 wire (20 amp) and all my lights with 14 wire (15 amp). The newer led lights are so efficient that 20 amp circuits are overkill. Each standard led recess or puck light I count as 1 amp load, and so I can put 12 lights on each one without worrying about coming close to overloading it. With how bright leds are, you can light up an entire floor of a house on just two 15 amp circuits.


01:39PM | 11/28/20
My house was built in 1999. The kitchen outlets are on a 20A circuit breaker. There are a total of 9 outlets on the circuit: 3 outlets are wired directly to the circuit, 1 outlet is a 20A GFCI to which the other 5 other outlets are connected. One of the 5 outlets is an exterior outlet.

Does this sound safe and to code?

I was trying to calculate actual amps when various appliances were in use. I calculated 2,400 Watts would be 20Amps. Can 20 amps be exceeded for short periods of time? For example my coffee maker is 1400w but only takes a few minutes to brew the coffee. If I made 4 slices of toast at the same time (1800w) I'd be pulling 26.6 amps for a few minutes. Is that okay to do occasionally or to be avoided?


10:21PM | 06/23/21
Look guys the truth of the matter is 1) 15A circuits and wiring are CHEAP. 2) 20A circuits and wire are EXPENSIVE.

Some people asked if they can just change a 15A outlet to a 20A outlet. It depends on a WHOLE lot of things. If this is the ONLY appliance on the circuit, it's likely fine (but not legal many places). Also, if you read the wattage of wire and the distance it has to travel, a shorter circuit is going to work MUCH better. The longer the run the higher the losses. Also HEAT! If you live in a cold climate it's less likely to give you issues than say Houston TX (100F sometimes).

AND - what size wire did they run? In a lot of older homes (70-120 years) I come across, they actually ran larger wire which is rated for 20A. #12. #14 is generally for 15A circuits. But that was probably added later (1950s+).


10:29PM | 06/23/21
And to answer the above question most appliances that use a lot of power are when they kick on and off (fridge, AC, etc.). A hairdryer is a definite exception. Under most circumstances you're probably not going to have issues, but running the coffee maker AND the toaster oven at the same time will likely trip the circuit. I had a microwave, tea maker, toaster oven, and coffee maker all hooked up on one circuit - run the microwave and toaster oven at the same time pop goes the circuit. Here you may want an electrician to "split" the circuit. What I mean is, you actually run 2 circuits to the same place and in effect get 30-40A. Top outlet and bottom outlet on the same receptical are actually running on different circuits now. Never pops a circuit anymore...


06:22PM | 11/28/21
I would not run 20A for lighting. This is because although you can get a 20A switch, breaker and 12# wire, the problem is the 14 AWG wire in the light. The wire gauge has to be sufficient thru the whole circuit. This is because your fault may not be a complete fault, but a partial fault causing high resistance / heat but not blow the breaker.

So rule is that all conductors need to be sized for your upstream breaker. As such, you don't mix conductors, and if you are wiring in a light, it will probably only have #14 AWG wire on it, and therefore, should not exist on a 20A circuit.

For example, that is why on your Christmas lights, there is that fuse pushed into the plug, so they can run low end wire, and be protected, because they fused upstream below your breaker.

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