Hand dryer

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hhsting

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I have hand dryer(s) fed from panelboard and Panelboard schedule shows load of 2326 va at 208V single phase. The engineer provided 30A breaker to feed those hand dryer(s).

What NEC 2017 section covers overcurrent protection sizing of hand dryers? I assume hand dryers have motors in them. I looked in NEC 2017 Article 422 but I dont see hand dryers overcurrent protection sizing. I assume hand dryer has motors
 
I don't have the book in front of me but by memory in the 2017 I believe that for an appliance the max OCPD is 150% of the nameplate.
 
infinity said:
I don't have the book in front of me but by memory in the 2017 I believe that for an appliance the max OCPD is 150% of the nameplate.
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NEC 2017 Article 422.11(E)That is for single non motor operated appliances. I think hand dryers have motors so that would not apply.

NEC 2017 Article 422.11(G) has something for motor operated appliances which but talks about overload nothing about overcurrent protection sizing
 
I have also tried to find NEC guidelines for hand dryers. The closest I got is 422.

422.11(G) Motor operated appliances.
States that "Where appliance overcurrent protective devices that are separate from the appliance are required, data for selection of these devices shall be marked on the appliance"

I presume it is true for many motor operated appliances that overcurrent protective devices that are separate from the appliance are not required. It is possible that the hand dryer in question has internal fuse type overcurrent protection and is therefore largely agnostic to the rating of the supply circuit. Now the supply circuit is just a set of feeders that simply requires 100% non continuous load rating minimum.

One set of instructions for Xlerator hand dryers state "Identify the voltage of your Dryer from the rating sticker of the unit. Then connect to a dedicated branch circuit not exceeding 20 Amp", despite the actual load being 5.5-12A depending on the voltage. 208 is specifically is 5.6A.

The only way to know for sure if a 30A breaker is a problem is to see what the instructions say for the specific hand dryer that is getting installed.

2326va seems like a strange number though. That number means this manufacture would not be able to have a 120v version of that unit without moving to a 30A circuit, which the industry generally doesn't do outside of niche things. A hand dryer manufature would not want to put their unit in a "niche" electrical requirement catagory. Xlerator dryers are, as another example, 1200-1400va no matter what voltage option you choose. The engineer might be making up those numbers. You would have to check the specifications for the hand dryer. Again, the instructions will (hopefully) tell all.
 
EngineeredElectric said:
I have also tried to find NEC guidelines for hand dryers. The closest I got is 422.

422.11(G) Motor operated appliances.
States that "Where appliance overcurrent protective devices that are separate from the appliance are required, data for selection of these devices shall be marked on the appliance"

I presume it is true for many motor operated appliances that overcurrent protective devices that are separate from the appliance are not required. It is possible that the hand dryer in question has internal fuse type overcurrent protection and is therefore largely agnostic to the rating of the supply circuit. Now the supply circuit is just a set of feeders that simply requires 100% non continuous load rating minimum.

One set of instructions for Xlerator hand dryers state "Identify the voltage of your Dryer from the rating sticker of the unit. Then connect to a dedicated branch circuit not exceeding 20 Amp", despite the actual load being 5.5-12A depending on the voltage. 208 is specifically is 5.6A.

The only way to know for sure if a 30A breaker is a problem is to see what the instructions say for the specific hand dryer that is getting installed.

2326va seems like a strange number though. That number means this manufacture would not be able to have a 120v version of that unit without moving to a 30A circuit, which the industry generally doesn't do outside of niche things. A hand dryer manufature would not want to put their unit in a "niche" electrical requirement catagory. Xlerator dryers are, as another example, 1200-1400va no matter what voltage option you choose. The engineer might be making up those numbers. You would have to check the specifications for the hand dryer. Again, the instructions will (hopefully) tell all.
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Drawing show he is connecting three hand dryers to that circuit. I read somewhere if its motor loads in NEC 2017 Article 430 then 100% for non continuous load should not apply. However i cant seem to find it??? Not sure if its there or not
 
Oh it's there, but I don't think article 430 applies to hand dryers. I think a hand dryer is an article 422 motor operated appliance. 422 does state "The ampacities of branch-circuit conductors for motor operated applicances not having a marked rating shall be in accordance with Part II of Article 430", but I'd wager that these hand dryers probably have a marked rating.

If there are 3 on a circuit then that is another issue. That may be against manufacturer instructions, as quoted above. (Again, you will have to check the instructions for the specific unit in question to see if that is the case not) Also, kind of bad design from a load balancing standpoint. Seems like hooking up the 3 hand dryers in a 3 phase 120 volt Y configuration is obviously preferable setup. Maybe the engineer is trying to balance some other unbalanced load, idk.

Since the NEC does not layout specific instructions for hand dryers, I would follow the manufacturer instructions first, then apply the general provisions of 422 second.

Whether you are looking at 422.10(A) for branch circuit ampacity, or 422.11(A) for overcurrent protection, or 422.11(G) for motor operated appliance requirements, the NEC always refers back to what is marked on the appliance.

You need to know what is marked on the appliance.
 
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