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Switch Rating #91957
02/14/05 01:05 AM
02/14/05 01:05 AM
G
George Little  Offline OP
Member
Joined: Jan 2004
Posts: 1,498
Michigan USA
If we have a separate circuit rated 20a - 120v, and a single receptacle controlled by a switch, does the switch need to be rated for 20a?


George Little
2017 / 2014 NEC & Related Books and Study Guides
Re: Switch Rating #91958
02/14/05 02:13 AM
02/14/05 02:13 AM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,366
Estero,Fl,usa
Yes


Greg Fretwell
Re: Switch Rating #91959
02/14/05 07:46 AM
02/14/05 07:46 AM
I
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
George L. you sure know what questions to ask. [Linked Image]

I agree with Greg, but the NEC IMO is not so clear.

2002 NEC. 404.14 in part states;

Quote
404.14 Rating and Use of Snap Switches.
Snap switches shall be used within their ratings and as indicated in 404.14(A) through (D).


OK, shall be used within their ratings IMO requires us to use the rating of the branch circuit.

210.3 in part states;

Quote
the ampere rating or setting of the specified overcurrent device shall determine the circuit rating.


Seems cut and dry so far but when we go back to 404.14(A) and (B) IMO it gets less clear.

Quote
404.14(A) Alternating Current General-Use Snap Switch. A form of general-use snap switch suitable only for use on ac circuits for controlling the following:

(1)Resistive and inductive loads, including electric-discharge lamps, not exceeding the ampere rating of the switch at the voltage involved

(2)Tungsten-filament lamp loads not exceeding the ampere rating of the switch at 120 volts.


Why tells us the loads can not exceed the ratings of the switch if the switch must be rated at least as high as the branch circuit?

The code and common sense already require that the load can not exceed the circuit rating.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: Switch Rating #91960
02/14/05 01:04 PM
02/14/05 01:04 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,366
Estero,Fl,usa
It is a winding road to get there but if you have a single receptacle on a 20a circuit it has to be a NEMA 5-20 and that encourages using a piece of equipment > 15a nominal so the switch controlling it should reflect that anticipated load.
That said I have seen regular 43 cent snap switches controlling 1hp 120v motor loads but I wouldn't want to bet on how long they will last.


Greg Fretwell
Re: Switch Rating #91961
02/14/05 01:32 PM
02/14/05 01:32 PM
I
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Quote
if you have a single receptacle on a 20a circuit it has to be a NEMA 5-20 and that encourages using a piece of equipment > 15a nominal so the switch controlling it should reflect that anticipated load.


I agree but it really does not say that about the switch very clearly. [Linked Image]


Bob Badger
Construction & Maintenance Electrician
Massachusetts

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