Bathroom heater switch requirements

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Onlyincali

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Please excuse my ignorant question in advance, I did however search and came up short.

I believe house wiring requires a roughly 20% "wiggle room" in sizing circuits. IE: You cant use a 15amp circuit for a 13 or 14amp requirement. Right?

Are switches the same or are they rated for what they will truly support? My bathroom heater/light/fan (Panasonic whisperwarm) requires a dedicated 20amp circuit. The heater portion alone uses 1400watts. I'm looking at 3 in 1 switches that will safely support this unit. Broan makes a 15amp switch in which each of the 3 switches is rated for 15amps. Will the 15amp rated switch be appropriate for a 1400 watt (roughly 12.5-13 amps) heater? 13/15 is roughly 85-90%. Is this usage acceptable or do I need a 20amp switch?

Thank you in advance
 
Based on 404.14 I see no problem.

As far as the "wiggle room", in general the Code allows a 15 amp non-continuous load on a 15 amp circuit including devices.

It gets a little hairier with 404.14 in that a motor is mist likely involved with the heat but it is doubtful that you will exceed the requirement sof 404.14 and IF the unit and switch are supplied by the manufacturer as a "unit", IMO, we are covered by 110.3(B).
 
Onlyincali said:
Please excuse my ignorant question in advance, I did however search and came up short.

I believe house wiring requires a roughly 20% "wiggle room" in sizing circuits. IE: You cant use a 15amp circuit for a 13 or 14amp requirement. Right?

Are switches the same or are they rated for what they will truly support? My bathroom heater/light/fan (Panasonic whisperwarm) requires a dedicated 20amp circuit. The heater portion alone uses 1400watts. I'm looking at 3 in 1 switches that will safely support this unit. Broan makes a 15amp switch in which each of the 3 switches is rated for 15amps. Will the 15amp rated switch be appropriate for a 1400 watt (roughly 12.5-13 amps) heater? 13/15 is roughly 85-90%. Is this usage acceptable or do I need a 20amp switch?

Thank you in advance
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You can load a 15A circuit to 15A if non-continuous; heated bath fans are continuous loads, thus the 20A circuit req. and yes, those ~$50 3-1 mfg switches for heated and illuminated bathroom fans are fine for the purpose.

eta: 1400W heat is <12A, closer to 11.7A. You can run that thru a 15A switch all day long w/o problems.
 
JFletcher said:
You can load a 15A circuit to 15A if non-continuous; heated bath fans are continuous loads, thus the 20A circuit req. and yes, those ~$50 3-1 mfg switches for heated and illuminated bathroom fans are fine for the purpose.

eta: 1400W heat is <12A, closer to 11.7A. You can run that thru a 15A switch all day long w/o problems.
Click to expand...

Great, thanks guys! I chose this $18 switch from Amazon, it appears that each of the three switches is 15A. http://www.amazon.com/Decora-R42-01...&redirect=true&ref_=oh_aui_detailpage_o00_s00

For some reason, the heater has an individual neutral for EACH system (heater, fan, light, night light). I plan on running a single neutral to the unit and simply sharing them with all 4 functions. I'm assuming this is ok seeing how its all 12g wiring, right? I find it odd the unit isn't setup with a common/shared neutral from the factory.

Just for future reference, what is the required "wiggle room" for continuous loads on wiring/outlets/switches?

Thank you again for your time, I ALWAYS learn when I'm on this forum.
 
JFletcher said:
You can load a 15A circuit to 15A if non-continuous; heated bath fans are continuous loads, thus the 20A circuit req. and yes, those ~$50 3-1 mfg switches for heated and illuminated bathroom fans are fine for the purpose.

eta: 1400W heat is <12A, closer to 11.7A. You can run that thru a 15A switch all day long w/o problems.
Click to expand...

Where would I find in the NEC that a bathroom HVL is a continuos load? Yes, they could be turned on for more than 3 hours but they gennerally are not automated.
 
JFletcher said:
Learn something new every day; never heard of such an animal until your post. Fairly common up north?
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Pretty common, I have a 275 gallon tank in my basement, the fill pipe and vent run outside so the truck driver can fill it.

I can run diesel or kerosene in it as well, this is handy when I forget to schedule a delivery. :ashamed1:
 
JFletcher said:
Learn something new every day; never heard of such an animal until your post. Fairly common up north?
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You've never had the pleasure of having oil heat? :lol: It is extremely common in the northeast as heating fuel where natural gas is not available. Our electricity rates are prohibitively expensive to use that for heating, so fuel oil rules the day. Propane has been gaining popularity in the last decade or so. Heat pumps don't work so well here either.
 
peter d said:
You've never had the pleasure of having oil heat? :lol: It is extremely common in the northeast as heating fuel where natural gas is not available. Our electricity rates are prohibitively expensive to use that for heating, so fuel oil rules the day. Propane has been gaining popularity in the last decade or so. Heat pumps don't work so well here either.
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Our house had oil fired central heat for 20 years, was dicey the last several when it didnt start and we had to manually prime it. Lasted over 40 years tho with no repairs; I certainly cant say the same for the heating and air unit we've had for the last 15, which, aside from the exterior case, has pretty much been piecemeal replaced over the years. Never heard of an oil-fired water heater for a residence tho.
 
JFletcher said:
Our house had oil fired central heat for 20 years, was dicey the last several when it didnt start and we had to manually prime it. Lasted over 40 years tho with no repairs; I certainly cant say the same for the heating and air unit we've had for the last 15, which, aside from the exterior case, has pretty much been piecemeal replaced over the years. Never heard of an oil-fired water heater for a residence tho.
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They are very rare even here in the land of oil heat. They are expensive to install and don't last long due to the intense heat inherent in burning oil. Most oil systems use an indirect water heater.
 
peter d said:
They are very rare even here in the land of oil heat. They are expensive to install and don't last long due to the intense heat inherent in burning oil. Most oil systems use an indirect water heater.
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My folks house had an oil fired water heater but yes I agree less popular

My house is an oil fired steam boiler with a tankless water heater option.
 
iwire said:
My folks house had an oil fired water heater but yes I agree less popular

My house is an oil fired steam boiler with a tankless water heater option.
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So what is the required "wiggle room" for continuous loads? IE: whats the max cont. load you can run through a 15a circuit?
 
Onlyincali said:
So what is the required "wiggle room" for continuous loads? IE: whats the max cont. load you can run through a 15a circuit?
Click to expand...

A 15 amp breaker can be loaded to 15 amps for periods not exceeding 3 hours.

If the load is expected to run longer than 3 hours the 15 amp breaker can be loaded to only 12 amps.
 
Onlyincali said:
So what is the required "wiggle room" for continuous loads? IE: whats the max cont. load you can run through a 15a circuit?
Click to expand...

iwire mentioned the 15A circuit already, but any continuous load can only be 80% of the circuit's max ampacity, so 16A for a 20A circuit, 24A for a 30A circuit, 32A for a 40A, 40A for a 50A, etc.
 
Now throw in the 100% rated device and add some confusion;)

Onlyincali, you won't find such devices in residential (probably shouldn't say never but the chances are maybe only .00001%, so generally consider everything to be only rated for 80% if there is a continuous load.
 
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