General duty snap switch question.

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Ajr188

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New York
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electrician
I got a question that came up on my test and for some reason I felt it was a trick question.

test question states

what is the largest load you can put on a 15 amp general duty snap switch?

I went over to 404.14 and my answer would be 15 amps

can someone please help!?
 
A search for NEC 404.14 provided this as the first hit. Maybe it was the same point your question was trying to test:

Question # 2 Is it legal to install a 15 amp rated light switch on a 20 amp branch circuit. The load of the permanently wired luminaires (not cord and plug) is considerably less than 15 amps. I have looked under article 210 and 404 and cannot find where it would not be legal for this application.


Answer # 2 NEC 404.14 NEC 404.14 is helpful in understanding the requirement. It reads: 404.14 Rating and Use of Snap Switches. Snap switches shall be used within their ratings and as indicated in 404.14(A) through (F). The current code requires two current related things of the branch circuit conductors. 1) That they have sufficient ampacity for the load served. 2) That they be suitably protected by the OCPD feeding the circuit. But code only requires one current related thing of switches: 1) that they be rated for the load served. NEC 404.14. The switch only sees the current that will be passing through the load it serves. If that load is under 15 amps, you can use a 15 amp switch to control it. If a given switch serves a load that exceeds 15 amps, then that switch must be rated for more than 15 amps
 
Trying to think of a way to complicate this and call it an unanswerable question 😂. Continuous load? I don't see any requirement to derate a switch for continuous loads. What about if it's the disconnect or controller for a motor?
 
Trying to think of a way to complicate this and call it an unanswerable question . Continuous load? I don't see any requirement to derate a switch for continuous loads. What about if it's the disconnect or controller for a motor?

Therein lies the “trick” part of the question. Even though there may be certain scenarios where the current might be limited to a value less than 15, those are, by definition, no longer the maximum.

The maximum is definitely 15.
 
I got a question that came up on my test and for some reason I felt it was a trick question.

test question states

what is the largest load you can put on a 15 amp general duty snap switch?

I went over to 404.14 and my answer would be 15 amps

can someone please help!?
Can not remember if it was my sparky dad, Vo Tech class or during an apprenticeship many years ago was told to always use the 80% rule so I never used a 15 amp toggle switch for more then 12 amps. Even went the extra mile and always used a spec grade 20 amp toggle switch on all residential garbage disposals. Never had trouble with 250 & 600 volt fusible safety switches using the 80% rule along with quality fuses. I rather spend a little more money then get a call back a few years later. You did not mention what type of load that you want to use a 15 amp toggle switch on. For all LED'S probably would not be a problem. A high inrush load like an air compressor should use a Manuel starter switch. Installed a 120 volt Manuel starter on my washing machine & gas dryer 45 years ago. The one for washing machine tripped out a few times when I forgot to remove short pieces of #10 solid copper wire that jammed water pump up.
 
I think the correct answer is 15 amps unless the load is a motor.

Used to be that a switch on a motor had to be rated in HP. If it is not rated in HP it had to be rated 2x the motor full load

430.83 c 1 still is that way
 
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