Commercial Bathroom Hand Dryers

[CFL]

Yeah, that was my thought too, but I hear the Xcelerator "FEEL THE POWER"! may very believably be more than 1/8 hp of motor-driven appliance- they are powerful! Thus, some difficulty with 422.30(C).

5/8 hp motor, 970w heating element.

 

[Cavie]

Thanks for the informative replies. I think that I will play it safe and install a double pole switch 20amp rating in the drop tile ceiling attic above the hand dryer.

And if you had a hard ceiling? Very interesting.

 

[brother]

But if 422.31(C) applies the branch circuit breaker can be the disconnecting means, but it must be within sight of the appliance, locking device is still optional and not required in this case.

Ok, I see what you guys are referring too. We are still under the NEC 2008 version, not the 2011. Under the 2008 he would be fine with the breaker lock. I wonder what Code cycle is the op under?

From reading the 2011NEC, I believe 430.109 (A) (5) would come into play. Since that hand dryer is a 'listed' self contained unit and has a 'controller' timer and overload integral part of it, I believe it complies with (5)Self-Protected Combination Controller. Therefore it complies with 422.31 (C) 2011 version.

 

[kwired]

Ok, I see what you guys are referring too. We are still under the NEC 2008 version, not the 2011. Under the 2008 he would be fine with the breaker lock. I wonder what Code cycle is the op under?

From reading the 2011NEC, I believe 430.109 (A) (5) would come into play. Since that hand dryer is a 'listed' self contained unit and has a 'controller' timer and overload integral part of it, I believe it complies with (5)Self-Protected Combination Controller. Therefore it complies with 422.31 (C) 2011 version.

422.31(B) allows the remote branch circuit overcurrent device that has a permanent installed locking means to serve as the disconnecting means in both 2008 and 2011. Somehow I missed that earlier, but was pretty sure that a lock on the breaker was permitted. I did read this section, but apparently not careful enough the first time.

Point is kind of moot, based on 422.31(B) but anything in 430 doesn't apply to this installationunless something in 422 sends you to 430, it is not a motor, it is an appliance that contains a motor.

 

[augie47]

I also would look at it as an appliance containing a motor and apply 422.31, but there certainly is room for a different opinion.

 

[brother]

422.31(B) allows the remote branch circuit overcurrent device that has a permanent installed locking means to serve as the disconnecting means in both 2008 and 2011. Somehow I missed that earlier, but was pretty sure that a lock on the breaker was permitted. I did read this section, but apparently not careful enough the first time.

Point is kind of moot, based on 422.31(B) but anything in 430 doesn't apply to this installationunless something in 422 sends you to 430, it is not a motor, it is an appliance that contains a motor.

So the placing of the permanent locking device on the breaker should cover this issue and make it code compliant you think? What about 2008 NEC 422.32 since it motor driven? They appear to contradict each other when you first look at it but one deals with a motor, and the other does not (ie water heaters) appliances. Also, article 430 would still apply unless it was specifically amended by article 422. 2008 NEC 422.3 Scope says so. No need for 422 to send you to 430, because 430 is already in affect.

It appears his 'snap' switch maybe the only true way to go on this hmmm.

 

[kwired]

So the placing of the permanent locking device on the breaker should cover this issue and make it code compliant you think? What about 2008 NEC 422.32 since it motor driven? They appear to contradict each other when you first look at it but one deals with a motor, and the other does not (ie water heaters) appliances. Also, article 430 would still apply unless it was specifically amended by article 422. 2008 NEC 422.3 Scope says so. No need for 422 to send you to 430, because 430 is already in affect.

It appears his 'snap' switch maybe the only true way to go on this hmmm.

This is not a motor, it is an appliance that happens to contain a motor. The motor is actually the smaller load of the appliance and the heater is the greater load, so I don't even know if it should be called a motor driven appliance, the motor is more of an aux. component, but yet an important one, the heater is more of the main feature of the appliance.

I see there is no definition for "motor driven appliance". To me it means there is a motor that drives the main functions of the appliance. This is more obvious on things like a disposer, or a dishwasher, but not so clear on things like a furnace, a gas water heater with draft motor, or a hand dryer, where the motor is definitely important to the functioning of the appliance but the motor itself doesn't really perform the primary function of the appliance either.

 

[brother]

This is not a motor, it is an appliance that happens to contain a motor. The motor is actually the smaller load of the appliance and the heater is the greater load, so I don't even know if it should be called a motor driven appliance, the motor is more of an aux. component, but yet an important one, the heater is more of the main feature of the appliance.

I see there is no definition for "motor driven appliance". To me it means there is a motor that drives the main functions of the appliance. This is more obvious on things like a disposer, or a dishwasher, but not so clear on things like a furnace, a gas water heater with draft motor, or a hand dryer, where the motor is definitely important to the functioning of the appliance but the motor itself doesn't really perform the primary function of the appliance either.

I hear your points. But I do disagree with you about the motor not driving the main functions of the appliance. The main function of a hand dryer is to 'dry your hands'. Even if you didn't have the 'heat' at least with the motor you can use air to dry your hands even though not as quickly. So this 'motor' is driving the main function of this appliance. So I see this as a 'motor driven appliance' that falls under 422.32. When they, UL , listed it together , (motor and heater for the hand dryer) it became one unit as a motor driven appliance. I would see this as the same for a furnace etc... because of the way UL listed it.

 

[kwired]

I hear your points. But I do disagree with you about the motor not driving the main functions of the appliance. The main function of a hand dryer is to 'dry your hands'. Even if you didn't have the 'heat' at least with the motor you can use air to dry your hands even though not as quickly. So this 'motor' is driving the main function of this appliance. So I see this as a 'motor driven appliance' that falls under 422.32. When they, UL , listed it together , (motor and heater for the hand dryer) it became one unit as a motor driven appliance. I would see this as the same for a furnace etc... because of the way UL listed it.

draft
How about the gas water heater with a blower for combustion air?

That motor is kind of important, but at same time if you find some other way to make the air flow, the appliance will still perform it's main function.

 

[Volta]

draft
How about the gas water heater with a blower for combustion air?

That motor is kind of important, but at same time if you find some other way to make the air flow, the appliance will still perform it's main function.

Maybe with those other items. But I gotta tell you, any heat from the xcelerator is besides the point. The motor is so strong the output nearly takes your skin off! They ain't kidding with their motto. :happyyes:

 

[GoldDigger]

Maybe with those other items. But I gotta tell you, any heat from the xcelerator is besides the point. The motor is so strong the output nearly takes your skin off! They ain't kidding with their motto. :happyyes:

And AFAIK, the new Dyson models do not use heat at all.

 

[hurk27]

Looking at the wording in 422.31(A) and (B) seems to me to indicated that under a total rating of 300va or 1/8hp motor the breaker supplying the circuit would be allowed as the disconnect without a locking device on the breaker, and over this it would require the locking device on the breaker, but when we get to 422.32 if its a motor only appliance and over 1/8hp it needs to be within sight, such as a garbage disposal?

My question is why do they think that it is safer to work on a appliance that is less then 300va or 1/8hp with only using the breaker as the disconnect???? you still have the circuit voltage and current to deal with? a repairman could get lit up just as bad, someone dropped the ball on this rule.

It just does not follow any safety logic at all:? sounds like something else push thru by the manufactures??

 

[iwire]

Wayne, when I have pondered this in the past the conclusion that I came up with is that is has to do with being injured by the mechanical aspects of the motor not the shock hazard.'

Doubtful small motor will produce a significant physical injury. Even if it geared way down for power the speed would be such you would move a finger before losing it.


Of course all of the above is just speculation and I have no proof that is what the CMP was thinking but I think it also goes along with why motors have few expectations for in sight disconnects, IMO it is about the rotation of the motor not about a greater shock hazard than other electrical equipment.

 

[Volta]

Wayne, my guess is that under that level of current draw it was deemed safe enough to disconnect that load live. That basic language existed in 1947, though not in '40. Certainly long before we considered arc-flash of worker safety anything like we do now.

Reasonable? I can't say.

 

[Volta]

I am not sure that it is just about the motor hazards per se, as the wattage for other appliances is also limited.

 

[iwire]

I am not sure that it is just about the motor hazards per se, as the wattage for other appliances is also limited.

I am having a hard time following everyone's thoughts here but it is my understanding a non-motor appliance above or below 300va does not need an in sight disconnect.


But as I said I am not sure what each person is specifically talking about.

 

[iwire]

I am not sure that it is just about the motor hazards per se, as the wattage for other appliances is also limited.

Looking back on Wayes post he seems to have two different issues going on.

Looking at the wording in 422.31(A) and (B) seems to me to indicated that under a total rating of 300va or 1/8hp motor the breaker supplying the circuit would be allowed as the disconnect without a locking device on the breaker, and over this it would require the locking device on the breaker, but when we get to 422.32 if its a motor only appliance and over 1/8hp it needs to be within sight, such as a garbage disposal?

My post was relating to the black text above.

As far as the red text that may just go back to 'practical safeguarding'?

 

[Volta]

Well, as far as myself, I was speculating that the reasoning behind this 'exception' to the 'normal' rule of a disconnect within sight may not have that much to do with rotating machinery as the text has paired 1/8 hp with 300 va for at least 55 years, and as I have never seen a '42 or '43 Code (very rare) I simply assume that they entered at the same time. With the va limit it seems to me that the concern may have been more about the current draw itself than the type of work the energy was used for.

But that's just a guess.

 

[kwired]

And AFAIK, the new Dyson models do not use heat at all.

I was going to mention that it may be possible to create a certain amount of heat just from a high volume of air flow. At a dairy plant I used to do work they had an evaporator for condensing whey (or really any liquid that you may want to reduce the amount of water content). I never really fully understood just how everything worked on that equipment, but I do know they had a 250 HP turbo fan on a VFD, (back when they were at least 5-6 times larger than it would be today), and part of how they controlled heat in the process was by varying the speed of that fan - and it was not a case of higher speed means cooler operation, in this case higher speed created more friction and more heat.

Looking at the wording in 422.31(A) and (B) seems to me to indicated that under a total rating of 300va or 1/8hp motor the breaker supplying the circuit would be allowed as the disconnect without a locking device on the breaker, and over this it would require the locking device on the breaker, but when we get to 422.32 if its a motor only appliance and over 1/8hp it needs to be within sight, such as a garbage disposal?

My question is why do they think that it is safer to work on a appliance that is less then 300va or 1/8hp with only using the breaker as the disconnect???? you still have the circuit voltage and current to deal with? a repairman could get lit up just as bad, someone dropped the ball on this rule.

It just does not follow any safety logic at all:? sounds like something else push thru by the manufactures??

Wayne, when I have pondered this in the past the conclusion that I came up with is that is has to do with being injured by the mechanical aspects of the motor not the shock hazard.'

Doubtful small motor will produce a significant physical injury. Even if it geared way down for power the speed would be such you would move a finger before losing it.


Of course all of the above is just speculation and I have no proof that is what the CMP was thinking but I think it also goes along with why motors have few expectations for in sight disconnects, IMO it is about the rotation of the motor not about a greater shock hazard than other electrical equipment.

iwires comment is kind of how I understand this requirement also. Thinking about how far back this requirement goes, and the fact that the disconnect isn't necessarily totally intended to be a disconnect for electrical energy only it does make some sense. If an operator needs to make adjustments or other routine service to the driven load, disconnecting power to the motor is a little like turning off the fuel to a gasoline powered version of the same machine, or pulling the spark plug(s) or other methods of ensuring the engine can not run unexpectedly.

I also think it was accepted at one time that 1/8 hp was an acceptable level where the available mechanical energy was low enough the hazards were somewhat minimal, but electric shock or arc flash were not really seen as much of a concern at that time. I would not be surprised to see changes to this sometime in the future, but then again electrical maintenance is where the shock and flash hazards are going to be more of a risk and maybe having a lockout being remote from the motor/appliance is seen as more acceptable in this situation, IDK, just a guess.

 

[Cavie]

My head hurts. Install a breaker lock out and say good night.