15/20 Amp receptacle conductor size?

Status
Not open for further replies.
M

meleck

Member
I am designing a system for 120VAC wiring of a truck sleeper cab and want to follow NEC as close as possible. In this design, a 20 amp circuit breaker has three receptacles coming off in parallel. The first is a 20 amp receptacle with 12/3 wire. The other two receptacles are 15 amp. Are these 15 amp receptacles considered taps and can I use 14/3 wire to connect them to my 20 amp breaker? Note the 15 amp receptacles cannot be changed to 15/20 receptacles and are only regulatory approved to 15 amps. Any help is appreciated.

(Moderator?s Note: Edited to remove email address. If you wish to send an email to this person, then first send a Private Message within the forum, and ask for the email address.)

[ April 23, 2004, 12:26 PM: Message edited by: charlie b ]
 
Re: 15/20 Amp receptacle conductor size?

I suppose you could wire a truck cab to the specs of the NEC, however it is not within the scope of the NEC.

Also, I am an electrician, and I do not do Electronic Equipment Engineering because of my lack of education, training, and experience with that profession. Are you sure you are qualified to perform this type of electrical work?

You conductor size, in most cases, cannot be smaller than the rating of the protection device. Per the NEC, 15-ampere receptacles are permitted to be 20-ampere branch circuits under certain considerations. :)
 
Re: 15/20 Amp receptacle conductor size?

Bryan, actualy this could possibly be an article 551 issue.

meleck, start with that article.

Roger

[ April 23, 2004, 12:30 PM: Message edited by: roger ]
 
Re: 15/20 Amp receptacle conductor size?

Hey Roger,

Good call, "Truck Camper" is actually defined in Article 551, except for the word portable? I'm picturing the cab fixed to a big Mack Truck. :confused:
 
Re: 15/20 Amp receptacle conductor size?

We in the trucking industry have created our own standard that is a combination of NEC Article 551 and UL/CSA standards. We have been installing these UL approved systems on trucks since 1996. It is just now that the industry is really picking up on it because of idle reduction laws for trucks. As an example, we only allow the use of stranded wire and crimped connections because of the vibration considerations.
I have contacted NFPA several times about including a new section for trucks and truckstops but they have not been interested. As such we have a committee at SAE that is developing a standard for 120VAC on trucks.

Getting back to my question. NEC Article 551.43(c) allows 15Amp receptacles to be protected by 20 circuit breakers. Should the conductor between the breaker and the 15 amp receptacle be 14 or 12 AWG? Personally, I think it is crazy to allow a 15 amp receptacle on a 20 amp breaker because there is nothing stopping the user of the 15 amp duplex receptacles from plugging in two appliances with more than a 15 amp draw.
Thanks
 
Re: 15/20 Amp receptacle conductor size?

melek:

To answer your question you must run wire sized for the circuit breaker.

You can put 15 amp rated receptacles on a 20 amp circuit only if there is more than one receptacle on the circuit.

If you use a duplex 15 amp receptacle on a 20 amp circuit than you have put two receptacles on the circuit. Each of these receptacles is capable of handling 15 amps. If you plug in two pieces of equipment that exceed the rating of the circuit than the CB is there for that.

I do not seem to share in your concern.
If you were to use 20 amp receptacles on a 20 amp circuit than you have the ability to draw even more than if you use 15 amp receptacles.

I hope this helps you.
 
Re: 15/20 Amp receptacle conductor size?

You can have one 15 ampere duplex receptacle on a 20 amp circuit and still be with in code, you are not required to have two different receptacles to meet this code .

John
 
Re: 15/20 Amp receptacle conductor size?

Your correct, I mis understood what you originally posted because I did not read it completely..

drg
 
Re: 15/20 Amp receptacle conductor size?

To recap, I can protect more than one 15A receptacle (duplex or otherwise) with a 20A circuit breaker if the entire circuit is rated 20A. This means that the wire between the 15A receptacle and 20A breaker must be at least 12 gage (or rated over 20A). Please correct me if the above statement is wrong. Thank you all for your time in helping me.
 
Status
Not open for further replies.
Top