Leviton No. 1755 - 3 switches - wiring

[windward]

I bought a Leviton no. 1755 switch that has three switches. I am using it to install an exhaust fan that also has a fluorescent light and a small night light. I was reading the instructions (might be the first time) and it says the common should be "Only #12 AWG"' yet you can use 14 AWG for the load lines.

If my exhaust unit is less than 15amps, why would I need a 12awg common?
Does a 12 AWG common do any good if you are picking up power from a 14ga line?

Thanks
Matt


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[wyliesdiesels]

The only thing i can think of is to prevent overheating the neutral due to possible harmonics from the loads...u obviously cant overload the neutral since a #14 should be protected with a 15a OCPD...

 

[nehog]

Because the total current it can handle is 20 amps, and each device has a maximum of 15 amps. (So for example using crude computations, one circuit is 10 amps, and the other two are 5 each for a total of 20 amps...)

 

[wyliesdiesels]

Because the total current it can handle is 20 amps, and each device has a maximum of 15 amps. (So for example using crude computations, one circuit is 10 amps, and the other two are 5 each for a total of 20 amps...)

However, if the hot feeding the switch is #14, then the max ampacity of the OCPD and therefore the circuit is 15. So even though the seitch is rated at 20a, only 15a will flow before the breaker trips...the circuit conductors will be either #14 or #12 and u wouldnt have a #14 neutral with a #12 hot!

 

[windward]

The switch is only rated for 15Amps. The exhaust fan with both lights is only drawing 51 watts. I cannot imagine needing to feed the switch with 12AWG wire.


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[wyliesdiesels]

The switch is only rated for 15Amps. The exhaust fan with both lights is only drawing 51 watts. I cannot imagine needing to feed the switch with 12AWG wire.


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If u read at the top of this u will see its rated for 20a max:

http://communities.leviton.com/servlet/JiveServlet/downloadBody/1920-102-1-2845/Ins 1754 1755.pdf

 

[windward]

Okay, that makes sense. I thought the total switch was only rated for 15A.

This is why this forum is so great.


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[nehog]

However, if the hot feeding the switch is #14, then the max ampacity of the OCPD and therefore the circuit is 15. So even though the seitch is rated at 20a, only 15a will flow before the breaker trips...the circuit conductors will be either #14 or #12 and u wouldnt have a #14 neutral with a #12 hot!

Absolutely. The 12 AWG spec is so it can be used at full rating. As long as the circuit is properly protected (15 Amp breaker) then 14 AWG is fine.