Do I really need a 20-amp circuit for this?

[jumper]

Where does the code specify primary heat source. I have put the heater part on a t-stat in the past.

Okay I will concede that it could be considered space heating, then you would have to reconcile the following statement with 424.3(B).

In general the heat is required to be 125% but not the light & fan. All that doesn't matter if the manufacturer requires a 20 amp cir anyway and I believe the calc. would still be over 15 amps

424.3 Branch Circuits.
(B) Branch-Circuit Sizing. Fixed electric space-heating
equipment and motors shall be considered continuous load.

And if the fan and heat are considered continuous, then the light is considered.......?

 

[petersonra]

what difference does it make cost wise? A few dollars? do what the instructions say and be done with it.

 

[templdl]

what difference does it make cost wise? A few dollars? do what the instructions say and be done with it.

That was my thought also.

 

[iwire]

IDK, I think that it is more of of an appliance IMO, the heater is only really intended to heat part of the space for a limited amount of time. It is not the primary source of heat for the bathroom.

Take a look at the scope of 424

424.1 Scope. This article covers fixed electric equipment used for space heating. For the purpose of this article, heating equipment shall include heating cable, unit heaters, boilers, central systems, or other approved fixed electric space-heating equipment. This article shall not apply to process heating and room air conditioning.

Notice it says for space heating, not primary or central heating.

 

[kwired]

Art 422 is the general "appliances" section.

Unless something falls in the following sections 424 - 440 which are for specific appliances, it is covered in 422.

424.1 Scope.
This article covers fixed electric equipment used for space heating. For the purpose of this article, heating equipment shall include heating cable, unit heaters, boilers, central systems, or other approved fixed electric space-heating equipment. This article shall not apply to process heating and room air conditioning

.

If it heats a space and is not process heating or room air conditioning then 424 applies.

 

[brother]

Okay I will concede that it could be considered space heating, then you would have to reconcile the following statement with 424.3(B).



424.3 Branch Circuits.
(B) Branch-Circuit Sizing. Fixed electric space-heating
equipment and motors shall be considered continuous load.

And if the fan and heat are considered continuous, then the light is considered.......?

I was looking in my 2008 NEC and didn't see the part that said, "and motors". I see it was added in 2011 NEC. I suppose it only makes sense for the motor of a heating unit be considered continuous.

 

[brother]

A fan/light/heater is just a space heater combined with a light and fan. Is there some difference between the heat of a ceiling mount fixture and say a wall mounted space heater?

Not in my opinion. That's why I say it falls more under the 2008 NEC 424 article.

 

[Dennis Alwon]

Okay I will concede that it could be considered space heating, then you would have to reconcile the following statement with 424.3(B).



424.3 Branch Circuits.
(B) Branch-Circuit Sizing. Fixed electric space-heating
equipment and motors shall be considered continuous load.

And if the fan and heat are considered continuous, then the light is considered.......?

Why would the light be considered continuous. The motor can be considered continuous but the 125% on the heat should cover that. NO?

 

[iwire]

We are really getting into odd territory as the item is a unit with a label so we do not calculate each item separately.

That said if we were too;

1) The light could be called continuos or not. It would depend on the use

2) The exhaust fan motor would be required to be counted at 125% per article 430 if is larger than...

3) ... The heater blower motor at 100 or 125% dependent on which motor is larger

4) The heater element at 125% due to article 424


But why would we do all that? The instructions say 20 amp circuit.

 

[templdl]

We are really getting into odd territory as the item is a unit with a label so we do not calculate each item separately.

That said if we were too;

1) The light could be called continuos or not. It would depend on the use

2) The exhaust fan motor would be required to be counted at 125% per article 430 if is larger than...

3) ... The heater blower motor at 100 or 125% dependent on which motor is larger

4) The heater element at 125% due to article 424


But why would we do all that? The instructions say 20 amp circuit.

I've been watching this string of posts and comparing the time invested in tryiing to justify a 15a circuit verses just installing a 20a as iwire said and calling it a day.

 

[mwm1752]

Why would the light be considered continuous. The motor can be considered continuous but the 125% on the heat should cover that. NO?

My kids had definitely left the bath lights on for more than 3 hours -- even though the unit falls under article 424 which appears to define it as a continuous load there is no auto controlled to turn the d------m thing off -- back to "no controllable events or personel"

20 amp circuit all day long -- cowboy up with the makeup part

 

[templdl]

All in favor of a 20a circuit say 'aye.'

 

[trojans4]

Agree in just following the instructions on a 20 A circuit but just a side note. Most of those units have wiring compartments which are too small for conveniently folding 12 AWG back into especially if you use 12/4 to switch all three components. Even if you only switch two and use 12/3 it is not easy.

 

[mjf]

Agree in just following the instructions on a 20 A circuit but just a side note. Most of those units have wiring compartments which are too small for conveniently folding 12 AWG back into especially if you use 12/4 to switch all three components. Even if you only switch two and use 12/3 it is not easy.

Yep, nobody ever told me this profession was going to be convenient or easy.

 

[John120/240]

Agree in just following the instructions on a 20 A circuit but just a side note. Most of those units have wiring compartments which are too small for conveniently folding 12 AWG back into especially if you use 12/4 to switch all three components. Even if you only switch two and use 12/3 it is not easy.

Yep, nobody ever told me this profession was going to be convenient or easy.

Yes it can be frustrating the first few times you wire something unfamiliar. With experience you will learn just how long to cut your wires. Long enough to attach the fixture wire, but not so long as to prohibit getting your wires in the box. Next time, try to pre fold your #12's before you attach the fixture leads.