Switch For Fan/Heater Unit On 20A Circuit

[DerbyDad03]

I have some questions related to the switches that can/should be used for a fan/heater combination unit.

I want to install a Panasonic FV-11VH2 in my bathroom. The unit requires a 20A circuit, which I assume is because of the heater. I will be pulling a dedicated 20A circuit using 12-2 w/ground from the basement to the attic for this unit, but I'm a tad confused about the switches.

On this page there are 2 switches that I am considering. One of them is a humidity sensing switch (FS-100), the other is a 2 function toggle switch (FSR-500).

I'm not sure which switch I want to use. Obviously if I use the FS-100 for the fan, I'll need a separate switch for the heater. If I decide to forgo the humidity sensor, I'll use the FSR-500, assuming it's OK to use based on my questions below.

Here are my questions:

Regarding the FS-100 Humidity Sensing switch:

The only rating I see for the FS-100 humidity sensing switch is "Maximum Fan Load: 1/8th hp or 3 amps".

1 - Do I need to be concerned as to whether the switch is rated for 15A or 20A?

2 - Since I will be using 12-2 w/ground for the 20A circuit, do I need to run 12-2 to this switch also, regardless of it's rating?

Obviously this switch will only be used for the fan portion of the unit, which would normally only require a 15A circuit, but I'm not sure how the wiring rules deals with the switch and/or switch leg for a 20A circuit. Note: this switch requires a neutral wire, so space in the box may also be an issue, especially if I need to use 12g.

Regarding the FSR-500 2 function toggle switch:

The website says these 3 things:

- Compatible with ALL makers of Fans, Lights, Heaters - Best for use with: a fan/light combination, a fan/heater combination, or a 2-speed fan - Maximum Total Load: 15 amps

1 - So, if the fan/heater unit itself requires a 20A circuit, am I allowed to use a switch rated for 15A?

2 - Do the wires need to be 12g to the switch? (I'm pretty sure I know that answer to but I just want to make sure.)

Thanks.

[philoÂÂ]

The wires going to the fan switch do not have tp be rated at 20 amps. 15 amp wiring is OK

The heater will of course require a 20 amp switch or more. You'd never want to use a 15 amp switch for a 15 amp load.

[trader4]

I would say no. The fan is within the switch rating. This is like installing a ceiling fan control or light dimmer. There are millions of light dimmers out there that are rated for say 700W max and they are on 15A, 20A light circuits.

Yes. You kind of wind up doing that anyway no? They are probably going in the same box, so what's left, some pig tails?

No

And I wouldn't use that $18 switch. There should be similar cheaper 20A switches available at HD, electric supply, etc.

Yes.

[David L. Martel]

Derby,

Your unit draws more than 12 amps, so it needs 20amp wiring, fusing. That's what needs to go to the switchbox from the main panel . The heater draws just under 12 amps. So the wiring to and switch for the heater should be for 20 amps. Neither of the switches that you are looking at can handle 20 amps. Any hardware store will have 20 amp switches in many styles and colors. Your fan draws 1/4 of an amp. It will happily work with the humidity sensor switch. 12-2 is overkill for the fan but you've already got it so use it. So, in sum, use 12-2 throughout, get a 20 amp switch for the heater and the snazzy FS-100 for the fan. Try to match the 20 amp switch style to the FS-100. Get your wife's approval on the switch style, color, and switchplate.

Dave M.

[micky]

I wonder if this is related to the problem. Switches are not meant to be compatible with the makers of heaters. They can be compatible with all makes of heaters. But not all models.

So since the OP is using a big heater, he can't use this switch. The big heater is not one of the models it's compatible with, even if it claims to be compatible with all makers.

[trader4]

I don't believe that is correct. There may be some exceptions where a tap can use conductors that are less than that required by the breaker, but I don't believe this is one of them. AFAIK, if the breaker is 20A, then all the wiring connecting everything needs to ge 12G.

[bud--]

That is actually if the load is "continuous", which is over 3 hours. It may be on that long. DD says the manufacturer wants a 20A circuit.

If you load a breaker over 80% and the load is on for over 3 hours the breaker may trip. That is the only reason I know of for the 80% rule.

The wiring has to be #12 because the circuit is #12.

The switch can be 15A. I would likely use a spec grade (better quality).

You need #12 because the circuit is #12.

I agree the humidity switch should be fine.

Dewstop - if the total load is 15A or less and Dewstop is rated 15A you could use it. But it is expensive. Is it UL listed?

[gfretwell]

I looked up the specs on this "Combined Amps 12.2 "

A 15a switch will be fine since switches are selected based on the load, not the circuit ampacity. The switch that says "max 3a" is only good if you are switching the fan. The heater would smoke it pretty quickly.

All of the wire in the wall needs to be sized to the over current device (20a=12g copper). There are some exceptions but this is not one.

[trader4]

I don't see why the dewstop has to be rated at 15A. The fan draws less that an amp. It's controlled by that electronic dewstop gizmo. That would seem to me to be just like putting a ceiling fan controller or a light dimmer that rated at 700W on any light circuit, be it 15A,

20A, etc. The light dimmer can't handle 15A, yet it's apparently code compliant, no?

[DerbyDad03]

Everything you have said is basically what I expected to hear.

I have a couple of other questions, based on the info in this document:

First "question" - I'm pretty sure I've got this right, please verify.

The first switch in the document - FV-WCCS1 - is what I am planning on using for the fan. It's a Humidity Sensing switch rated for 15A.

The last switch in the document - FV-WCD01 - is what I am planning on using for the heater. It's a count down timer switch rated for 20A.

That seems OK to me.

Second "question" - mostly just a curiosity.

I'm a bit confused by the switch directly above the FV-WCD01, specifically FV-WCSW41. It contains 3 independent rocker switches, each rated for 15A, but also says that the total switch amperage is 20A. It also says that it is designed for the FV-11VHL2, which has a fan, heater and light. So does that mean that if I wanted to, I could use a 15A switch for the heater in my FV-11VH2, which is basically the same unit but without the light? In other words, if I had 2 separate 15A switches, one for the fan and one for the heater, that would be OK, right?

Thanks again for the help.

[gfretwell]

Since the total load is 12.2a, a 15a switch would run the whole thing. Recommending a 20a circuit is reading the code in the strictest sense. A 1440 watt heater is all you can put on a 15a circuit, based on 80%. Adding that 200ma fan, technically puts you over but not enough to keep me up at night.

Bear in mind, the 80% cushion is already built into 240.4(D) where they say you need 14 gauge wire on a 15a breaker and 12ga on a 20.

[bud--]

If all you are handling is the fan you don't need 15A, which I said above for the humidity sensor.

DD also talked about using a "2 function switch" which would presumably switch the heater.

After looking again, price for the humidity sensor looks OK.

I like timers for bath fans, where you can run it for 5 minutes after you leave (or whatever). The fan control has a timer too.

[DerbyDad03]

I ended up ordering a _real_ humidity sensor switch made by Leviton after reading the reviews on the Dewstop FS-100. That's the actual switch that Panasonic sells with their label.

Turns out the FS-100 is a non-adjustable _condensation_ sensing switch which many people were not happy with. Seems that the FS-100 didn't come on until the walls were dripping wet, especially depending on the placement of the switch. Someone said it had to be really close to the shower and up high to even activate.

The Leviton IPHS5-1LW got better reviews and seems like a better switch for my needs. As long as I was buying Leviton, I also ordered the Leviton LTB60-1LZ countdown timer. It's rated for 20A so it should work fine with the heater.

I ran the wire to the attic last night. Now I need a deep 3 gang box and a Leviton dimmer for the light. The current fan timer and light switch are in

2 separate switch boxes but I want to clean that up a bit. I'll need a deep box because all of the switches are pretty big and there will be a bunch of 12g wire in the box. Luckily it's going in the wall where the main stack runs so it's an extra deep wall. I could fit a switch box as deep as a shoebox in there. Hey, that's an idea...I may just try that. ;-)