Does the NEC...

Does the NEC prohibit placing 15 amp receptacles on a 20 amp branch circuit
in residential construction? If so, can you cite the specific Code section
please?
Reply to
Randy Jones
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There are rules in the 2002 NEC that allow you to install a 15 ampere receptacle on a 20 ampere circuit in dwelling units where there are more than one receptacle on a general use 20 ampere branch circuit. However, the maximum load is limited to 12 amperes for the total cord and plug connected load. How one regulates this load is a real problem because it is not uncommon to buy appliances that require a load in excess of 12 amperes. This becomes even more complicated when we look at the appliance rules in Article 422. In 422.11 (E) (2) we find that a non motor operated appliances can be used on a 20 ampere circuit (the rating of the overcurrent protective device ie. circuit breaker) if the appliance is rated 13.3 amperes or less which gives permission to aplliance manufacturers to supply appliances that operate at up to 13.3 amperes.. Combining these two sections must mean that if a appliance is rated over 12 amperes but less than or equal to 13.3 amperes, a 20 ampere receptacle would be required on a 20 ampere maximum circuit. Additionally, some local and State modifications to the NEC may require that you install 20-ampere receptacles on 20-ampere branch circuits. I would check with my local Authority Having Jurisdiction(AHJ.) Table 210.24 Summary of Branch-Circuit Requirements also has additional requirements. "210.24 Branch-Circuit Requirements - Summary. The requirements for circuits that have two or more outlets or receptacles, other than the receptacle circuits of 210.11(C)(1) and (2), are summarized in Table 210.24. This table provides only a summary of minimum requirements. See 210.19, 210.20, and 210.21 for the specific requirements applying to branch circuits." Also Section 210.23 should be complied to for permissible loads: "210.23 Permissible Loads. In no case shall the load exceed the branch-circuit ampere rating. An individual branch circuit shall be permitted to supply any load for which it is rated. A branch circuit supplying two or more outlets or receptacles shall supply only the loads specified according to its size as specified in 210.23(A) through (D) and as summarized in 210.24 and Table 210.24. (A) 15- and 20-Ampere Branch Circuits. A 15- or 20-ampere branch circuit shall be permitted to supply lighting units or other utilization equipment, or a combination of both, and shall comply with 210.23(A)(1) and (A)(2). Exception: The small appliance branch circuits, laundry branch circuits, and bathroom branch circuits required in a dwelling unit(s) by 210.11(C)(1), (2), and (3) shall supply only the receptacle outlets specified in that section. (1) Cord-and-Plug-Connected Equipment. The rating of any one cord-and-plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating. (2) Utilization Equipment Fastened in Place. The total rating of utilization equipment fastened in place, other than luminaires (lighting fixtures), shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied."
Here are some of the rules:
210.21 Outlet Devices. (B) Receptacles.
(1) Single Receptacle on an Individual Branch Circuit. A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit. Exception No. 1: A receptacle installed in accordance with 430.81(C). Exception No. 2: A receptacle installed exclusively for the use of a cord-and-plug-connected arc welder shall be permitted to have an ampere rating not less than the minimum branch-circuit conductor ampacity determined by 630.11(A) for arc welders. FPN: See definition of receptacle in Article 100.
(2) Total Cord-and-Plug-Connected Load. Where connected to a branch circuit supplying two or more receptacles or outlets, a receptacle shall not supply a total cord-and-plug-connected load in excess of the maximum specified in Table 210.21(B)(2).
Table 210.21(B)(2) Maximum Cord-and-Plug-Connected Load to Receptacle
Circuit Rating (Amperes) Receptacle Rating (Amperes) Maximum Load (Amperes) 15 or 20 15 12 20 20 16 30 30 24
(3) Receptacle Ratings. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3), or where larger than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating. Exception No. 1: Receptacles for one or more cord-and-plug-connected arc welders shall be permitted to have ampere ratings not less than the minimum branch-circuit conductor ampacity permitted by 630.11(A) or (B) as applicable for arc welders. Exception No. 2: The ampere rating of a receptacle installed for electric discharge lighting shall be permitted to be based on 410.30(C).
422.11 Overcurrent Protection (E) Single Nonmotor-Operated Appliance. If the branch circuit supplies a single non-motor-operated appliance, the rating of overcurrent protection shall (1) Not exceed that marked on the appliance; (2) If the overcurrent protection rating is not marked and the appliance is rated 13.3 amperes or less, not exceed 20 amperes; or (3) If the overcurrent protection rating is not marked and the appliance is rated over 13.3 amperes, not exceed 150 percent of the appliance rated current. Where 150 percent of the appliance rating does not correspond to a standard overcurrent device ampere rating, the next higher standard rating shall be permitted.
Reply to
Gerald Newton
Thanks for the education. Given this information, I could argue that if I special ordered a 20A branch circuit in one room of a house being built, I could expect 20A receptacles.
receptacles,
210.11(C)(1),
Reply to
Randy Jones
You probably won't get them unless you spec'ed them since you said "receptacle(S)"
You will also have a 20 circuit in your laundry, bathrooms and two in the kitchen but they are usually installed with NEMA 5-15s. The currect interpretation is that a duplex outlet is "more than one" receptacle for the purposes of this rule. It is a minor change to put in the 5-20s but I bet the electrician doesn't have them on his truck if he builds high volume tract homes.
Reply to
Greg
Or if the builder standard is "Decora" outlets and switches which cost about 4x the cost of standard (at Home Depot anyway).
Reply to
Randy Jones
The code is just the minimum requirements. Personally, I would run 1/2 " EMT with raintight connectors and metal boxes with raised covers.I would put each receptacle on a dedicated 20 amp branch circuit, except for the kitchen, laundry, and bathroom. I would use 30 amp/#10 THHN on those.The last house I wired, I used four (4) electrical panels, each with a 200 amp main.I have never had a breaker trip. Total cost for the electrical in a the 1200 square foot house: $23, 468.57! Very economical! I am presently experimenting with using GFCI receptacles throughout the house, fed with Arc Fault breakers. I am determined to conquer and eradicate anyone getting shocked, except for the price! If you have to ask the price, you can't afford it! Have a nice day...
Reply to
Blue Crown
Larger wire is fine, but If your protective device is over 20A then this is a code violation for circuits feeding 15A or 20A receptacles. And if you limit the protective device, how do you insure that someone doesn't increase it later, thinking that it is a 30A circuit with the #10 wire?
Ben Miller
Reply to
Ben Miller
You are wasting time and money. No one wires a home like this. $23, 468 for wiring a 1200 sq foot home. You have got to be kidding!
Reply to
Gerald Newton
| The code is just the minimum requirements. Personally, I would run 1/2 | " EMT with raintight connectors and metal boxes with raised covers.I | would put each receptacle on a dedicated 20 amp branch circuit, except | for the kitchen, laundry, and bathroom. I would use 30 amp/#10 THHN on | those.The last house I wired, I used four (4) electrical panels, each | with a 200 amp main.I have never had a breaker trip. Total cost for | the electrical in a the 1200 square foot house: $23, 468.57! Very | economical! I am presently experimenting with using GFCI receptacles | throughout the house, fed with Arc Fault breakers. I am determined to | conquer and eradicate anyone getting shocked, except for the price! If | you have to ask the price, you can't afford it! Have a nice day...
If you are really intent on eradicating electrical shock you might want to consider attaching a motion detector to a shunt trip on the main. Then when humans arrive, all potential of electrocution is removed.
Is there a master main breaker? If not, is the service drop rated for 800 amp service?
Have you tested those GFCI/AFCI breakers under strong radio fields to be sure they don't trip due to the RF being sensed as current differential? That's a scenario where the apparent fault would continue even after the breaker contacts open, causing the trip solenoid to be continuously active, burn out, and cause a fire. Of course if you have to ask the price, you can't afford it.
Reply to
phil-news-nospam
| |> for the kitchen, laundry, and bathroom. I would use 30 amp/#10 THHN on |> those. | | Larger wire is fine, but If your protective device is over 20A then this is | a code violation for circuits feeding 15A or 20A receptacles. And if you | limit the protective device, how do you insure that someone doesn't increase | it later, thinking that it is a 30A circuit with the #10 wire?
You really can't protect against future stupidity by others. If someone wants to slap on a 30 amp breaker because the wire is AWG#10, that's their fault only. They shouldn't be changing breakers unless they know what the circuit is. The existance of a few morons in the worlds shouldn't restrict the rest of us from being able to enhance our own safety.
Sometimes you just have to run a larger wire, anyway. Longer runs need it to avoid voltage drop. Runs through hotter ambient temperature areas need it to stay within the insulation temperature rating.
As for the previous poster saying 30 amp, I wasn't sure if he meant that breaker was 30 amp, or the wire was 30 amp (no such thing, but lots of people seem to think so).
I plan to make my future house very electrical safe, but will also be doing a balancing act between various safety aspect (electrocution, fire), some other aspects (line noise, RFI), and economic (I won't be getting the very cheapest, but I won't be wasting my money, either).
Reply to
phil-news-nospam
Good idea on the motion detector! To answer your question # 1: Under the NEC, you are allowed 6 main disconnects. I have used only four, so I have the capability of adding 2 more! Might use them for HVAC, etc... I used a CT (current transformer) box, and let the power company worry about the service drop rating. They can derate quite a bit. Looks like they used #2. Funny looking as all git-out! I am having a hard time getting any work right now. After I bid on someone's house, they usually get someone to wire them for chicken feed! Tight asses! Also, the electrical inspectors are questioning my intelligence. What do they know, they are just ex-electrical contractors who got lazy and looked for the easy way out. Next time one of those pricks sticks me with a large gig sheet, I will hook up a megger and zap their ass! lol! Can you believe the last thing I got gigged on was having a smoke detector closer than 3 feet to the return air vent. They need to get a life! If I find out that they are picking on me, it will be WAR! Later...Blue Crown
Reply to
Blue Crown
I wish inspectors would RE-READ NFPA 72 in particular section 11.8.3.5 (6) which prohibits locating a smoke detector within 36" horizontal distance of a SUPPLY register. Nowhere have I found NFPA 72 to prohibit installation within 36" of a RETURN register.
Reply to
Randy Jones
It would depend if the branch circuit was a required 20A like for small appliance, laundry or bathroom.
Sincerely,
Donald L. Phillips, Jr., P.E. Worthington Engineering, Inc. 145 Greenglade Avenue Worthington, OH 43085-2264
snipped-for-privacy@worthingtonNSengineering.com (remove NS to use the address) 614.937.0463 voice 208.975.1011 fax
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Reply to
Don Phillips
How? The code says they are required to be 20a circuits and have no other outlets (with the "one bathroom" exception) but it doesn't say the receptacles have to be 20a.
Reply to
Greg

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