Electric Dryer at 15 amps

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Grouch1980

Grouch1980

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New York, NY
Hi all,
I was recently given a cut sheet for an electric dryer for an apartment. The cut sheet calls for a 15 amp, 120 volt circuit to feed the dryer.

Usually for electric dryers i see 30 amp, 208 volt circuit requirements that need a NEMA 14-30R receptacle on the wall to feed the dryer. And using the standard calculation, i would use 5,000 watts as a minimum when performing the feeder calculation serving the apartment.

Using the standard calculation method, do I still have to use the 5,000 watt minimum for this type of dryer? The client confirmed with the manufacturer that it is considered an electric dryer. There is no gas connection. But with a 15 amp circuit, this dryer would only be drawing 1000 watts, 1500 watts? Do I still have to go that high with the calculation by using 5000 watts?
 
220 part IV optional calculations

using the standard you have no choice that I can see
 
(2017) 220.82(B)(3) calls for using the nameplate rating for "(c) Clothes dryers that are not connected to the laundry
branch circuit specified in item (2)."

Cheers, Wayne
 
I can't use the optional calculation since this apartment is being fed by 2 feeders. And it's pretty much a gut rehab. almost everything is new.
 
Then you are stuck with 5000VA, as (2017):

220.54 Electric Clothes Dryers — Dwelling Unit(s). The load for household electric clothes dryers in a dwelling unit(s) shall be either 5000 watts (volt-amperes) or the nameplate rating, whichever is larger, for each dryer served. . . .

Cheers, Wayne
 
wwhitney said:
(2017) 220.82(B)(3) calls for using the nameplate rating for "(c) Clothes dryers that are not connected to the laundry
branch circuit specified in item (2)."

Cheers, Wayne
Click to expand...
yeah, this is the optional calculation... I can't use this since the apartment has 2 feeders serving it.
 
I wonder whether this may be what is called a heat pump dryer?
These are electrically powered, but dry more slowly and at a lower temperature. They use less heat for two reasons:
1. The heat is produced more efficiently by using a heat pump, and
2. They use a closed loop air circulation so they do not eject heat to the outdoors.
So they might not only use less energy but also use lower power because of the extended drying time. And they do not require venting, making them attractive compact laundry equipment in apartments and condos.
One obvious problem with this new type of dryer is that the NEC does not recognize its existence as a fundamentally different type of dryer.
To the potential argument that the electrical supply should support possible replacement by a conventional electric dryer, I counter that that would not be possible without installing a vent.
I wonder if an AHJ would accept the argument that it is actually a dehumidifier rather than a dryer?
 
More likely it's a condensing dryer that uses cold water for the condensing plate. But it could be a heat pump dryer.

There are heat pump dryers that use a standard 240V/30A circuit and are hardly slower than electric resistance dryers, but obviously a 1500W dryer (heat pump or condensing) would be quite a bit slower.

Cheers, Wayne
 
I wire a single machine that was both a washer and a dryer. It is european models at 120 v. I installed a 20 amp cir since code requires 20 amp for laundry.

That size unit will take a long time to heat but i suspect it is a very small unit and probably for a small apt or as a second macine for kitchen towels, etc.
 
wwhitney said:
Then you are stuck with 5000VA, as (2017):

220.54 Electric Clothes Dryers — Dwelling Unit(s). The load for household electric clothes dryers in a dwelling unit(s) shall be either 5000 watts (volt-amperes) or the nameplate rating, whichever is larger, for each dryer served. . . .

Cheers, Wayne
Click to expand...

Interesting. So in this case if you don't provide a 30A receptacle and circuit for a dryer do you even have an electric dryer according to 220.54? In other words, needing only a 15A circuit, it may as well be gas with no possibility of using a traditional electric dryer.

-Hal
 
GoldDigger said:
I wonder whether this may be what is called a heat pump dryer?
These are electrically powered, but dry more slowly and at a lower temperature. They use less heat for two reasons:
1. The heat is produced more efficiently by using a heat pump, and
2. They use a closed loop air circulation so they do not eject heat to the outdoors.
So they might not only use less energy but also use lower power because of the extended drying time. And they do not require venting, making them attractive compact laundry equipment in apartments and condos.
One obvious problem with this new type of dryer is that the NEC does not recognize its existence as a fundamentally different type of dryer.
To the potential argument that the electrical supply should support possible replacement by a conventional electric dryer, I counter that that would not be possible without installing a vent.
I wonder if an AHJ would accept the argument that it is actually a dehumidifier rather than a dryer?
Click to expand...
actually yes! it's a heat pump dryer. so you're saying the NEC doesn't recognize this type of dryer? am i forced to use 5kw for the feeder calculation, or would i be able to regard it as a gas dryer?
 
The standard calculation says to use 5000 watt... I believe that is to cover anyone upsizing the dryer. For calc purposes you need to use 5kw
 
Dennis Alwon said:
The standard calculation says to use 5000 watt... I believe that is to cover anyone upsizing the dryer.
Click to expand...

What if you are using a gas dryer? AFAIK you still don't have to figure an additional 5kw just in case someone will switch to electric someday.

You either have a 30A dryer or you don't. In this case he doesn't.

-Hal
 
Little Bill said:
How can you (legally) have two feeders serving a building? NEC says only one service or feeder.
Click to expand...
It’s a multifamily building with about 100 apartments. The building has one service. This apartment that were redesigning (one of the apts in the building) used to be 2 smaller apartments, and was merged into one large apt years ago. So it has 2 existing panels / feeders serving it.
 
There are a number of companies that sell what is called a "compact dryer". They run on 120 volts, and probably do use less than 15 amps. They use the standard way of drying, heated air from resistance heater. They are very small, the one I just looked at is 1.5 cu. ft. while Walmart lists regular dryers that are 6 or more cubic fee. There are also small washing machines, and these often stack in a small footprint.
 
15 amps @ 120 volts is only 1800 watts. Even if on a 20 amp circuit you won't be able to draw more than 2400 watts so I'd forget about any thoughts you are having about using a 5000 figure here.

Could still be worthwhile to run 10-3 just in case it ever gets changed to more conventional ~5000 watt 120/240 dryer though.
 
kwired said:
15 amps @ 120 volts is only 1800 watts. Even if on a 20 amp circuit you won't be able to draw more than 2400 watts so I'd forget about any thoughts you are having about using a 5000 figure here.

Could still be worthwhile to run 10-3 just in case it ever gets changed to more conventional ~5000 watt 120/240 dryer though.
Click to expand...
I'm leaning towards this. it's not a conventional dryer. so 5000 watts wouldn't apply.
 
It's an apples to oranges comparison, but my wife and I have 2 children living in Europe (UK and Spain). Their dryers have drain pans like simple dehumidifiers. They take longer than ours to dry a (smaller) load.
 
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