Can switches rated for 15A be used in a 20A circuit? I'm talking about a residential circuit used for lighting and receptacles. My first impression is no but after having asked around I have been told that this is common practice. Wouldn't the switch be a point for failure such as excessive heating if the current was over 15A but still under the limit to trip the 20A breaker? Thanks, jrb
15A switches
- Thread starter jrb
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Re: 15A switches
Jrb, see 404.14.
If you are feeding a single load at or above 15 amps then yes you would have to use a 20 amp switch, but if you are using a number of 15 amp switches on a 20 amp circuit, no one switch would be loaded that heavy.
Roger
[ June 14, 2004, 06:37 PM: Message edited by: roger ]
Jrb, see 404.14.
If you are feeding a single load at or above 15 amps then yes you would have to use a 20 amp switch, but if you are using a number of 15 amp switches on a 20 amp circuit, no one switch would be loaded that heavy.
Roger
[ June 14, 2004, 06:37 PM: Message edited by: roger ]
sfav8r
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Re: 15A switches
404-14(a) does not distinguish between circuits with one switch and circuits with 2 or more switches.
Logically, if you had 2,3 or more switches on the same branch circuit, there is a good probability that only one would be on, so in a practical sense, it doesn't matter if there is more than one switch on the circuit.
404-14 addresses the load *beyond* the switch (the switched load) and requires that it not exceed the switch rating.
Yes, a 15a switch on a 20a branch circuit, is, at least theoretically, the weakest link. However, keep in mind that this is the continuous load rating and is de rated.
Now to be devil's advocate..why not just throw in a 20a switch?
[ June 15, 2004, 01:30 AM: Message edited by: sfav8r ]
404-14(a) does not distinguish between circuits with one switch and circuits with 2 or more switches.
Logically, if you had 2,3 or more switches on the same branch circuit, there is a good probability that only one would be on, so in a practical sense, it doesn't matter if there is more than one switch on the circuit.
404-14 addresses the load *beyond* the switch (the switched load) and requires that it not exceed the switch rating.
Yes, a 15a switch on a 20a branch circuit, is, at least theoretically, the weakest link. However, keep in mind that this is the continuous load rating and is de rated.
Now to be devil's advocate..why not just throw in a 20a switch?
[ June 15, 2004, 01:30 AM: Message edited by: sfav8r ]
sfav8r
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Re: 15A switches
My point is that just because there are 2,3 or 10 switches on the same circuit, does not eliminate the possibility that one switch COULD be the only switch "on". This being the case, it really doesn't matter if there is more than one switch in the circuit.
That's why 404.14 speaks to the load AFTER the switch and does not address the number of switches on the circuit.
I didn't say that only one switch WOULD be used at a time. I said there is a POSSIBILITY that only one switch would be used at any given time.
My point is that just because there are 2,3 or 10 switches on the same circuit, does not eliminate the possibility that one switch COULD be the only switch "on". This being the case, it really doesn't matter if there is more than one switch in the circuit.
That's why 404.14 speaks to the load AFTER the switch and does not address the number of switches on the circuit.
pierre
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Re: 15A switches
When I first read Roger's post, I was not too sure, but after rereading the section, I agree with his post. It is the load in amperes that determines the usuage.
Pierre
When I first read Roger's post, I was not too sure, but after rereading the section, I agree with his post. It is the load in amperes that determines the usuage.
Pierre
Re: 15A switches
Hello Pierre,
Sfav8r, in your example of 10 switches, if these 10 switches operated (1) 60 watt lamp (1/2 amp) in 10 different rooms, why would you want to spend the extra money to install 20 amp switches verses 15 amp switches?
The switch could be fed from any size circuit as long as the current passing through the contacts does not exceed the switches rating, or other provissions of 404.14.
Roger
[ June 15, 2004, 04:40 PM: Message edited by: roger ]
Hello Pierre,
this is correct.
Sfav8r, in your example of 10 switches, if these 10 switches operated (1) 60 watt lamp (1/2 amp) in 10 different rooms, why would you want to spend the extra money to install 20 amp switches verses 15 amp switches?
The switch could be fed from any size circuit as long as the current passing through the contacts does not exceed the switches rating, or other provissions of 404.14.
Roger
[ June 15, 2004, 04:40 PM: Message edited by: roger ]
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