I think the point is that there is not a simple answer to the simple question. There's a "generally acceptable" answer, theres a "overly-anal AHJ answer", and there's a "the shows in 30 minutes and 2000 people are going to be really upset if everything's broken" answer, and understanding not only what, but why, and the history, allows you as a theatrical professional to make a more informed decision about how to accomplish what needs to be accomplished in a safe and efficient manner.
15 Amp Plug on 20 Amp Outlet
- Thread starterAndy Haefner
- Start date
Then you may remain more deeply ignorant in your craft, that choice is yours alone. I personally prefer to understand the rules I need to bend or break and the implications of doing so.
Robert Engel
Member
I know it's a little late to the party, but I am somewhat overly annoyed when people say things like "it's code," but don't provide the code reference. To answer the question: Yes, As long as a 20A branch circuit supplies two or more receptacles, you can have 15 or 20A rated receptacles (210.21(B)(3). And, if you have 20A rated T-slot receptacle, you can use 15A attachment plugs into such 20A receptacle (406.8).
Here are code references from the NEC 2011 for your viewing pleasure.
210.21 Outlet Devices. Outlet devices shall have an ampere rating that is not less than the load to be served and shall comply with 210.21(A) and (B)
[...]
(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.
[...]
(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 rated higher than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.
Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits
Circuit Rating (Amperes) Receptacle Rating (Amperes)
15 Not over 15
20 15 or 20
30 30
40 40 or 50
50 50
406.8 Noninterchangeability. Receptacles, cord connectors, and attachment plugs shall be constructed such that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended. However, a 20-ampere T-slot receptacle or cord connector shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Non–grounding-type receptacles and connectors shall not accept grounding-type attachment plugs.
Here are code references from the NEC 2011 for your viewing pleasure.
210.21 Outlet Devices. Outlet devices shall have an ampere rating that is not less than the load to be served and shall comply with 210.21(A) and (B)
[...]
(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.
[...]
(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 rated higher than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.
Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits
Circuit Rating (Amperes) Receptacle Rating (Amperes)
15 Not over 15
20 15 or 20
30 30
40 40 or 50
50 50
406.8 Noninterchangeability. Receptacles, cord connectors, and attachment plugs shall be constructed such that receptacle or cord connectors do not accept an attachment plug with a different voltage or current rating from that for which the device is intended. However, a 20-ampere T-slot receptacle or cord connector shall be permitted to accept a 15-ampere attachment plug of the same voltage rating. Non–grounding-type receptacles and connectors shall not accept grounding-type attachment plugs.
BillConnerFASTC
Well-Known Member
STEVETERRY
Well-Known Member
Err...not exactly--if we are in a theatre or other article 520 occupancy (underscores added for clarity), per 2017 NEC:
520.9 Branch Circuits. A branch circuit of any size supplying
one or more receptacles shall be permitted to supply stage set
lighting. The voltage rating of the receptacles shall be not less
than the circuit voltage. Receptacle ampere ratings and branch circuit
conductor ampacity shall be not less than the branch circuit
overcurrent device ampere rating. Table 210.21(B)(2)
and 210.23 shall not apply. The application of 210.8(B)(4)
shall not be required.
and:
520.67 Multipole Branch-Circuit Cable Connectors. Multipole
branch-circuit cable connectors, male and female, for flexible
conductors shall be constructed so that tension on the cord or
cable is not transmitted to the connections. The female half
shall be attached to the load end of the power supply cord or
cable. The connector shall be rated in amperes and designed
so that differently rated devices cannot be connected together;
however, a 20-ampere T-slot receptacle shall be permitted to
accept a 15-ampere attachment plug of the same voltage rating.
Alternating-current multipole connectors shall be polarized
and comply with 406.7 and 406.10.
Informational Note: See 400.14 for pull at terminals.
Bottom line: no 15A permanent receptacles on 20A branch circuits in 520 occupancies.
ST
Last edited:
STEVETERRY
Well-Known Member
Chris Pflieger
Well-Known Member
Mmmmm.... tell about your biiiiiig branch circuit....But, 1-900-ASK-STEVE has a certain poetry to it.
ST
Yeah? What are going to do with all those plugs?
Chris Pflieger
Well-Known Member
Drink service is a little slow.
It seems like the correct answer was delivered pretty quick, so if others tend to expand and go a little off topic... I, as many others, appreciate the opportunity to learn.
Chris Pflieger
Well-Known Member
JD
Well-Known Member
If HoW actually referred to "Houses of Worship", then you do have a gray area. I would think that although it is a worship space, it still would be under section 520.
BillConnerFASTC
Well-Known Member
STEVETERRY
Well-Known Member
Places of Religious Worship are Assembly Occupancies covered under NEC article 518:
518.1 Scope. Except for the assembly occupancies explicitly
covered by 520.1, this article covers all buildings or portions of
buildings or structures designed or intended for the gathering
together of 100 or more persons for such purposes as deliberation,
worship, entertainment, eating, drinking, amusement,
awaiting transportation, or similar purposes.
518.2 General Classification.
(A) Examples. Assembly occupancies shall include, but not be
limited to, the following:
Armories
Assembly halls
Auditoriums
Bowling lanes
Club rooms
Conference rooms
Courtrooms
Dance halls
Dining and drinking facilities
Exhibition halls
Gymnasiums
Mortuary chapels
Multipurpose rooms
Museums
Places of awaiting transportation
Places of religious worship
Pool rooms
Restaurants
Skating rinks
HOWEVER:
(C) Theatrical Areas. Where any such building structure, or
portion thereof, contains a projection booth or stage platform
or area for the presentation of theatrical or musical productions,
either fixed or portable, the wiring for that area, including
associated audience seating areas, and all equipment that is
used in the referenced area, and portable equipment and
wiring for use in the production that will not be connected to
permanently installed wiring, shall comply with Article 520.
So, it is likely that most large Houses of Worship are treated as theatres covered under article 520.
ST
BillConnerFASTC
Well-Known Member
Somehow if you are a participant here at CB, it seems more than "likely" where you work comes under 520. Further, I guess I wonder why if using stage and studio lighting equipment, one would not want to comply with 520.
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