ECN Forum
Posted By: iwire Indicating Switch Requirements for Motors - 07/06/03 04:12 PM
I got involved in a discussion on another forum about the requirements for indicating switches, 430.104 and 422.35

A house has an attic exhaust fan and the customer wants to switch it from more than one location, my feeling is once you have provided the required indicating type disconnect at the fan itself you could use 3 or 4 way switches throughout the house.

But there have been many that feel any switch for the motor must be indicating type ruling out control from more than one location.

I am prepared to it crow on this I have before and will again, but I would like to get some more opinions on this.

Thanks for any help even if it shows I am wrong, Bob
Bob,
The 3 or 4 way switches would actually be motor controllers and each of these switches would require a disconnect per 430.102(A). I see no way that a set of 3 way switches, with or without indication, can be used as the required means of disconnect for a motor. The means of disconnect must disconnect the conductors from the power source and a 3 way does not do that. The means of disconnect must be under the control of the person working on the equipment and the remote 3 way makes this control impossible.
Don
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/06/03 06:53 PM
Thanks Don, I did overlook the requirement for a disconnect at the controller.

So how do I control an attic or bathroom fan from 2 locations?

Bob

Oh and I am talking about switches in addition to and not in place of the required disconnect at the motor.

[This message has been edited by iwire (edited 07-06-2003).]
While it is a big "overkill" it appears that the only code compliant way to control a motor from two or more location is by using a remote control circuit and a contactor with a disconnect at the contactor. This is a case where "common sense" should be used and the 3 way switches should be permitted to control the motor without a disconnect at each switch as long as there is a disconnect at the motor.
Don
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/06/03 08:33 PM
Don OK, I will admit defeat in this, thank you for your replies even if it was the opposite of what I was hoping for. [Linked Image]

I think I will continue to use common sense as long as the AHJ is agreeable, I do not see me installing stop start stations in dwelling bathrooms.

Bob
Hello bob

Most dwelling bath fans are plug and receptacle connected inside the enclosure. I am sure that a 3 way switch to the bath exhuast fan is compliant. As far as the attic fan, that may be another story

Pierre
To add to my prior post.
I forgot to mention the indicating means required for the bath fan is the 'plug and receptacle' in the enclosure. When unplugged, I believe that indicates it is off.

Pierre
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/07/03 05:19 PM
Pierre

I certainly thought that as well but it seems to be otherwise [Linked Image]

Bob
Bob,
I agree that the use of the plug and receptacle at the fan provides an acceptable means of disconnect for the motor as required by 430.109(B).
Don
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/07/03 11:12 PM
Don now you have me confused that's easy to do. [Linked Image]

Quote
it appears that the only code compliant way to control a motor from two or more location is by using a remote control circuit and a contactor with a disconnect at the contactor. This is a case where "common sense" should be used and the 3 way switches should be permitted to control the motor without a disconnect at each switch as long as there is a disconnect at the motor

But then this.

Quote
I agree that the use of the plug and receptacle at the fan provides an acceptable means of disconnect for the motor as required by 430.109(B).
Don

What makes these two installations different from each other?

So if I can unplug the motor in my bathroom fan I can use 3 ways at each door to run the fan?

But If I put a single pole indicating switch at the motor as the required disconnect switch for a fan in the attic I can not use 3 way switches downstairs to turn the fan on and off?

I guess I am beating a dead horse because I am just not getting this.???????????

Thanks for your patience, Bob who is now considering making fries for a living. [Linked Image]




[This message has been edited by iwire (edited 07-07-2003).]
What's the horsepower rating of your motor?
This question hasn't been asked, and has a good deal of relativity...S
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/08/03 01:06 AM
The HP on the attic fan was not brought up by the original poster, but I think it would be safe to say less than 2 HP.
Bob,
There are two different disconnect rules involved in a motor circuit. 430.102(A) requires a disconnect within sight of the motor controller. There are no exceptions to this rule. In your example, the 3-way switches are acting as motor controllers and each must have their own disconnect. The second disconnect rule is for the motor itself and is found in 430.102(B). There are some exceptions to this rule, but none that would apply to a dwelling occupancy. Under the 2002 code wording, most motor circuits must have two disconnects, one at the controller and one at the motor. If the controller is at or within sight of the motor you could use a single disconnect for both. You can also use a single disconnect at the controller in the rare cases where the exceptions to 430.102(B) apply.
Don
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/08/03 01:56 AM
Don thanks again I think this the part I was missing.

Quote
If the controller is at or within sight of the motor you could use a single disconnect for both.

I will talk to the inspector if this ever comes up for real, and see if he is agreeable.

I got another one for you if you do not mind, this is a real situation that we do in a customers stores, we did not design it.

One roof mounted 120 volt exhaust fan to vent men's and ladies locker rooms.

Each room has one 2 pole switch at the door one pole of each runs the lights the other pole runs the exhaust fan.

The two switches are in parallel so one can be off and the fan can be on.
I would accept a single disconnect at the fan. While the code seems to require a disconnect switch for the fan (controller)switch(s), I have never seen such an installation.
Don
This is an intriguing thread.

There is an 80 unit 4 story multi-dwelling unit building that I have come to know. This is a high end complex in a great location.

The units are laid out so the laundrys are stacked four high. The four clothes dryers share a common vent pipe with 120 V Fractional HP roof mounted exhaust booster fan.

When a tennant changes clothes dryers, they must purchase an auxillary relay (usually an internal addition to the appliance itself) that closes its single pole, single throw contact whenever the clothes dryer is running.

Each dwelling unit has its own 120/208 1Ø metered service.

The roof top exhaust booster fan is supplied by power from the "house meter".

The 120 V 20 A exhaust booster fan power is brought from the "house panel" to the 1st Floor dryer and then on up through the 2nd, 3rd & 4th dryers (all SP relays in parallel), ending at the booster fan disconnect.

From what I have come to understand from this thread, with the 2002 NEC in effect, the next dryer that is replaced will need new wiring (contactor remote control with the contactor at the motor) to be compliant.

Does that sound right?

Al
It would be ok to have a disconnect at each relay (controller) and a disconnect at the fan.
Would somebody please explain what is meant by an "Indicating switch."

Indicating as in "ON/OFF" markings, pilot light, etc.?
Posted By: iwire Re: Indicating Switch Requirements for Motors - 07/10/03 08:11 PM
2002 NEC
Quote
404.7 Indicating.
General-use and motor-circuit switches, circuit breakers, and molded case switches, where mounted in an enclosure as described in 404.3, shall clearly indicate whether they are in the open (off) or closed (on) position.

Where these switch or circuit breaker handles are operated vertically rather than rotationally or horizontally, the up position of the handle shall be the (on) position.
Another scenario

The building (fictional) has a gas furnace. there is a safety disconnect at the furnace. there is another safety disconnect at the entrance to the furnace room. by nature of the room layout, this 2nd disconnect is not in sight of the furnace.
This is common in both dwelling units and non-dwelling units.
1. Is this 2nd switch considered a controller?
2. Does it require a disconnect?
3. The motor is less than 2 hp.

I am confused ?

BTW- I have come across this installation procedure many times.

Pierre
Pierre,
Those are both disconnects and are permitted by the code. The controller is the relay or control board within the furnace equipment.
Don
Posted By: engy Re: Indicating Switch Requirements for Motors - 07/11/03 08:35 PM
"The 3 or 4 way switches would actually be motor controllers and each of these switches would require a disconnect per 430.102(A)."

What about 430.111 ?
engy,
I forgot about that one.
don
Thanks, iwire -- I was trying to find that.
© ECN Electrical Forums