switch loop and polarity

[hammerash]

I am finishing up wiring for my new furnace. It required a power ventor and I also have humidifier. These are going on a single circuit separate from the furnace. they only draw a total of about 3 amps but that was enough to require new circuit. the power ventor has a control. The control gets the power and the ventor gets it power from the control. I figure I should put in a disconnect (switch) in this system. I plan to run the circuit into the control and then make a switch loop. The instructions say that it is polarity sensitive. So, here is plan-- white from panel will go to the area marked "neutral" and black will splice to a relabeled white on wire going to switch. The area on controller marked "hot" will connect to the black wire going to the switch. Will this be correct polarity?

oh the humidifier is corded plug so will not be part of this switch. It will have it's own outlet in same circuit.

[ray2047]

Polarity is not relevant to an AC circuit. It actually changes polarity 60 times a second. You are correct that the switch loop is on the hot side. Note size of wire for switch loop must match or exceed the circuit breaker requirement, #14 on a 15a breaker and #12 on a twenty amp breaker.

[hammerash]

thanks. I know that AC is 60Hz. I just asked about polarity because the instructions specifically state that one screw has to get hot wire and the other has to get neutral or damage to equipment may occur. So I just followed hot through the switch loop back to the unit. I actually ended up moving things around because the humidifier water line was over where I was going to put a box. So I ended up running to switch first and from there to the power ventor control unit, making my original question immaterial now.

since there is such little draw on this 15amp circuit, I was going to use it to put outlet in an adjacent crawlspace and an outlet or two in the furnace room (in addition to the outlet on the furnace for the humidifier.) My local jurisdiction does not have anything on this other than what is in NEC 2008. Since I don't have NEC 2008 nor do I know how to fully interpret it, any help would be appreciated.

[pcboss]

What they will probably consider is that the unfinished areas would require GFI protection for the receptacles.

[hammerash]

yes, was planning on making them GFCI--except the one where the humidifier plugs in since don't want nuisance tripping causing it to go off. Didn't they eliminate the exceptions for GFCI -a fixed appliance like frig in garage or garage door openers didn't need GFCI but now they do? This outlet will also be my outlet near furnace for being able to plug equipment in while working on it-so based on that it should probably have GFCI. Should I put a single receptacle, non-GFCI, for the humidifier and another one for near furnace? How close to furnace does a receptacle need to be?

[hammerash]

looked in one of my books (wiring-for pros by pros--reccomended by people on this forum) and it says under areas that need GFCI---"outlets for heating, AC, and refrigeration equipment" then under comments section it says "does not apply to evaporative coolers in one and two family dwellings" amd below table in note it says "new codes (depending on jurisdiction" may have removed the exceptions. see local inspector"

based on this and since my county on NEC 2008 and I did not find any thing on their paper regarding local addendums to NEC regarding this topic, I would assume that I have to have GFCI on the outlet near furnace, even where humidifier plugs in? But will have to ask inspector for sure i guess.

now it also says refrig equiment needs GFCI? This is not saying that your kitchen frig needs GFCI, is it? I did not think that was the case.

[John Nelson]

Although we could quibble about the correctness of the word "polarity", we all know what is meant in this context, and it is indeed important. But the description you provided in your first post does indeed have correct polarity, and you have wired the switch loop correctly.

Note, the term "polarity" is used many times in the National Electrical Code referring to AC circuits. So I believe we can properly use this term here.