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#182388 - 11/25/08 04:06 AM More than two 15A rated switches on 20A circuits  
Niko  Offline
Member
Joined: Aug 2006
Posts: 356
Campbell, CA
Table 210-21(B)3 allows 2 or more 15 & 20A receptacles on 20A circuits. what does the code say about 2 or more 15A rated switches on a circuit that is protected by 20A breaker?

Thanks for your comments.


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#182389 - 11/25/08 05:08 AM Re: More than two 15A rated switches on 20A circuits [Re: Niko]  
gfretwell  Online Content


Member
Joined: Jul 2004
Posts: 9,122
Estero,Fl,usa
Switches are really supposed to be rated for the load so a 15a switch on a 20a circuit is not a problem if it is a 15a (or less load). More of an issue, generally, is whether a switch is motor rated when it is a motor load. You have to watch out for this when you are using a snap switch for things like pool pumps and big "whole house" fans.


Greg Fretwell

#182393 - 11/25/08 09:52 AM Re: More than two 15A rated switches on 20A circuits [Re: gfretwell]  
IanR  Offline
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Joined: Dec 2004
Posts: 328
Palm Bay FL USA
"Switches are really supposed to be rated for the load"
So what about a 15A switch controlling a duplex receptacle, with a 20A breaker? Where you really can't determine what the load may be.


#182397 - 11/25/08 12:55 PM Re: More than two 15A rated switches on 20A circuits [Re: IanR]  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
I'ts quite simple, Ian.

Let's assume you have that switch operating a space heater, or other heavy load. The switch simply won't last very long, and stop being a switch. There might not even be any fireworks; the contacts just won't close anymore, and you get to replace the switch.

That's the whole point to the 'motor rating' idea. Motors, and some other loads, require a lot more than the rated current under specific circumstances .... so the switch will need to be able to handle those moments.

Once again, we come up against an example where 'trade practice' has been decades ahead of 'code.' In this instance, I'm referring to the trade proctice of separating the lighting circuits from the receptacle circuits, and using 15 amp circuits for lighting.


#182413 - 11/25/08 07:09 PM Re: More than two 15A rated switches on 20A circuits [Re: renosteinke]  
pdh  Offline
Member
Joined: Jan 2005
Posts: 354
The one switch failure I ever had was a "failed to OPEN" scenario. But that switch was very much abused.



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