Read Article 210-21(b) and tell me if you interpret it the same as me. I get the impression I could install a single 30 amp receptacle on a 20 amp individual branch circuit? What's up with that?
Mike,
I don't get that impression at all. The receptacle must be rated for at least what the circuit is rated for. So a 30 amp circuit would require at least a 30 amp receptacle, with the 2 exceptions that follow the article.
Also, take a look at table 210-24 on the next page. This makes it clear that a 30 amp circuit shall have a 30 amp receptacle (no other size) except as noted in note 2.
Tom
Tom,
Table 210-24 only applies to circuits with 2 or more outlets or receptacles. A single receptacle is covered only by 2109-21(b)(1). This section clearly requires that the receptacle have a rating at least equal to that of the branch circuit, but permits any single receptacle with a rating greater than the circuit rating to be installed. Now that I have said that the code would permit the installation of a 30 amp single receptacle on a 20 amp circuit, I will also tell you that the code says you can't really use it. 210-23 limits the load of any single cord connected equipment to 80% of the branch circuit rating. This would limit it to 16 amps in this case and I doubt if there appliances with 16 amp loads and 30 amp cord caps.
Don(resqcapt19)
Tom,
The phase "at least" means "a minimum of" to me. That could be construed by others to mean you can put a 30 amp receptacle on a 20 amp circuit. The article and notes you reference are for "two or more receptacles." I guess the NEC Wordsmiths like to keep us electricians confused and watch us scratch our heads trying to figure what the $%*! they mean. Are 40 rated receptacles still avaible? Thanks.
I'm looking at a Hubbell wiring device selector, which is by no means a complete selection and there are no 40 amp devices of any type shown.
210-7
Receptacles installed on 15 and 20 amp branch circuits shall be of the grounding type. Grounding type rec. shall be installed only on circuits of the voltage class and current for which they are rated, except as provided in Tables 210-21(b)(2) and (b)(3).
[This message has been edited by David (edited 04-24-2001).]