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Joined: Dec 2000
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What's the horsepower rating of your motor?
This question hasn't been asked, and has a good deal of relativity...S
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Joined: Jan 2003
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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 Badger
Construction & Maintenance Electrician
Massachusetts
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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
Don(resqcapt19)
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Don thanks again I think this the part I was missing. 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.
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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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
Don(resqcapt19)
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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
Al Hildenbrand
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It would be ok to have a disconnect at each relay (controller) and a disconnect at the fan.
Don(resqcapt19)
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Would somebody please explain what is meant by an "Indicating switch."
Indicating as in "ON/OFF" markings, pilot light, etc.?
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Joined: Jan 2003
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2002 NEC 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.
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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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 Belarge
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