Gas Dryers

[Grouch1980]

Hi,
I've come across gas dryers that draw about 10 amps, at 120 volts, for a residence. When you apply the demand factors of Article 220, would you classify these gas dryers under section 220.53? Thereby using 75% if we have 4 or more appliances?

Thanks.

 

[Dennis Alwon]

Section 220.53 states 75% for other than clothes washers, dryers etc... It doesn't give an exception for gas dryers so Imo, you cannot use the 75% rule

220.53 Appliance Load — Dwelling Unit(s). It shall be
permissible to apply a demand factor of 75 percent to the
nameplate rating load of four or more appliances fastened in
place, other than electric ranges, clothes dryers, space-heating
equipment, or air-conditioning equipment, that are served by
the same feeder or service in a one-family, two-family, or multifamily
dwelling.

 

[Grouch1980]

Good point. I should’ve read a little more of that section!! So since clothes dryers can’t be included, under which section would you include a gas dryer?

 

[Dennis Alwon]

I would just add it in under dryers @100% then you will get a demand factor at the end.

 

[augie47]

I agree with Dennis going by the literal wording of the NEC but since 220.54 and 220.55 specifically address electric clothes dryers and ranges, I would certainly be tempted to list the gas dryer as a 220.53 appliance.
Might be a good Code change to submit.

 

[Grouch1980]

I would just add it in under dryers @100% then you will get a demand factor at the end.

Hmm I don't follow. So take it at 100%... but which percentage am I applying at the end? Or you're saying just keep gas dryers at 100% throughout the whole calculation?

 

[Dennis Alwon]

If it is a dwelling you are taking the first 3,000 (standard) at 100% and the rest at 35%
If it the optional you have the first 10,000 at 100% and the rest at 40%
Going from memory on this

 

[Grouch1980]

If it is a dwelling you are taking the first 3,000 (standard) at 100% and the rest at 35%
If it the optional you have the first 10,000 at 100% and the rest at 40%
Going from memory on this

Oh I see. You're saying to apply the demand factor used for general lighting and receptacles, small appliance, and washer load to the gas dryer as well (using the standard calculation).

 

[Dennis Alwon]

Oh I see. You're saying to apply the demand factor used for general lighting and receptacles, small appliance, and washer load to the gas dryer as well (using the standard calculation).

Yes, the a/c and heat would not be under that demand but most everything else would be.

 

[gadfly56]

Section 220.53 states 75% for other than clothes washers, dryers etc... It doesn't give an exception for gas dryers so Imo, you cannot use the 75% rule

There is a certain ambiguity here. They use the word "electric" as an adjective to modify "ranges", but grammatically, this is a compound predicate (ranges, clothes dryers, space-heating equipment, or air-conditioning equipment). It is arguable that the word "electric" is meant to modify each element.

 

[Dennis Alwon]

There is a certain ambiguity here. They use the word "electric" as an adjective to modify "ranges", but grammatically, this is a compound predicate (ranges, clothes dryers, space-heating equipment, or air-conditioning equipment). It is arguable that the word "electric" is meant to modify each element.

I think the point is that clothes dryer are not meant to be an appliance whether gas or electric at least IMO.

 

[Dennis Alwon]

As written it does exclude dryers but it may not be the intent for gas dryers, but as written it does exclude them

 

[wwhitney]

As written it does exclude dryers but it may not be the intent for gas dryers, but as written it does exclude them

Unless you read it as "other than electric [ranges, clothes dryers, space-heating equipment, or air-conditioning equipment]". Then you could apply it to gas dryers, gas furnaces, and gas A/C, just like you can gas ranges.

Cheers, Wayne

 

[suemarkp]

I think they are covered like the washing machine - an item on the laundry appliance branch circuit which is 1500 watts in the calculation.

 

[K8MHZ]

I have a vent less wall space heater in my house. NG, piped, permanent. Lites using a piezo. No electricity going to it. Now, since I obviously wouldn't include the space heater in any load calcs, why would I calculate the load of a gas dryer based on the load of an electric one? Or am I missing something here? Or am I presenting a poor analogy?

 

[Grouch1980]

I have a vent less wall space heater in my house. NG, piped, permanent. Lites using a piezo. No electricity going to it. Now, since I obviously wouldn't include the space heater in any load calcs, why would I calculate the load of a gas dryer based on the load of an electric one? Or am I missing something here? Or am I presenting a poor analogy?

Not sure about the analogy... but in our case, an electric dryer would be based off of section 220.54. I don't have an electric dryer, i have a gas dryer, at 120 volts, 10 amps. So we're discussing what section to use. We're not using section 220.54 however, which is for electric.

 

[Dennis Alwon]

A gas dryer is basically a motor electrically speaking so you could calculate it as another motor.

 

[kwired]

I think they are covered like the washing machine - an item on the laundry appliance branch circuit which is 1500 watts in the calculation.

That's my thought. especially if you have washer and dryer on same circuit, you only then have one 1500VA laundry circuit to plug into the calculations.

Not sure about the analogy... but in our case, an electric dryer would be based off of section 220.54. I don't have an electric dryer, i have a gas dryer, at 120 volts, 10 amps. So we're discussing what section to use. We're not using section 220.54 however, which is for electric.

Electric dryer has a demand table because of the cycling of heating element during use. Gas dryer will be mostly steady load the entire time it is running nearly all that load is the tumbler motor. Heat cycling would impact gas usage but not electrical other than maybe less than 20 VA to operate a solenoid valve.

 

[Dennis Alwon]

Obviously this is not a clear cut situation. I don't think that it will make much of a difference anyway you do it. I would plug it in and see if it really puts you over. Oh and BTW, the optional calculation is generally much lower than the standard

 

[Grouch1980]

Obviously this is not a clear cut situation. I don't think that it will make much of a difference anyway you do it. I would plug it in and see if it really puts you over. Oh and BTW, the optional calculation is generally much lower than the standard

Understood. Thanks everyone for your feedback.