ECN Forum Forums Code Related Discussion NEC & other Code issues Re: Fan motors

Harold pointed out the article that allows the breaker to serve as the disconnect on small motors.
John pointed out why that may not be a good design or even a safe way to go.

This is one of those things where I would try to just cajole the installer to do the right thing without starting a wizzing contest.

IMHO, a chat with the electrician should solve this issue without any wizzing by all parties.

A small cost to install a box, switch & plate, and a few staples, & perhaps two NM connectors will save a lot of greif.

....and wizzing around wires and fan motors usually don't end well...

Is this Motor's Power Rating greater than 1/8 HP, but less than 2.0 HP?

Additionally, is the Blower Motor energized by more than One Source?

Section 430.109(B) allows for the use of the Branch Circuit Overcurrent Device to also serve as the Disconnecting means for Stationary Motors of 1/8 Horsepower (HP) or less.

Section 430.109(C) allows Disconnecting means for Stationary AC Motors - size above 1/8 HP, to 2.0 HP (connected to systems of 300V or less), to be either properly rated Snap Switches or Manual Motor Controllers.

Many small Fractional Horsepower AC Motors will be rated in Wattage, Equivalent to what is found at the Output (Motor Shaft).
If a Motor has a listed True Power Rating of 93 Watts, that would be 1/8 HP.

Any Wattage rating GREATER-THAN 93 Watts indicates a Motor with an output greater than 1/8 HP.

Consequently, any Wattage rating LESS-THAN OR EQUAL TO 93 Watts indicates a Motor with an output of 1/8 HP, or less.

Another Section in Article 430 may apply to Compliance is Section 430.102(B), Exception(a)... Where such location of disconnect means introduces increased hazards to personnel.
This would be applicable if the Blower Motor is on the same circuit as the Attic Lighting / General Equipment Service Receptacles.

As mentioned by others, it is a minimal cost involved to include a Snap Switch at the Blower, to serve as a Disconnecting means.
It is almost a "No-Brainer" (Default Installation Concept) for an Installation such as the one described in this Thread
(Exhaust Fan's Blower Motor is controlled from 2 or more Bathrooms).

Since the Exhaust Fan serves more than One Bathroom, the Blower _SHOULD_ be larger than 1/8 HP, in order to actually move enough Air to be considered an Exhaust Fan!
Regardless of which Bathroom Switch energizes the Motor, the Blower will still have to move the Air from all Bathrooms connected to the Exhaust Fan Assembly - via the connected Ducts.

Note: The above takes in to consideration that the Air Moving System is properly designed...

If the System has "Selective" possibilities - where the Ducts going to the Bathrooms have dampers, which are opened only when the Switch at that Bathroom is Closed, the Motor would be Speed Controlled according to the number of open dampers, yet will be of a full load size in the 1/4 to 1/3 HP range (if not larger).

These final comments are to indicate a Blower which exceeds 1/8 HP, and therefore does not qualify for the Disconnecting means permitted by 430.109(B).

Good luck!!

-- Scott (EE)

You guys are all right, and I went out yesterday and the EC did the right thing with a disconnect (snap switch) by each and every fan. This house had over 7 bathrooms and sauna and gym, etc. so there must have been at least 7-9 fans in this house. Some fans were operated from 2 bathrooms. Hence the need for a disconnect at the fan and not to rely upon the breaker lock. NOW comes a small twist to this story. There was a sub panel in the attic where several of the fans were located. The panel was in sight of every fan. He then could have used the breaker as a means of disconnect as long as the attic lights weren't on that circuit.

I think so if that is all true.

You must have a different kind of attic there if you can get all of the "space" requirements in front of a panelboard.

Pull down steps are fairly rare here and attics are "crawl on your belly" or at least "duck walk" affairs.

Greg:
Some of the 'attics' in my town could (and sometimes are) be used as habitable living space.

Think of a three story SFD kind of appearance.

Vertical furnaces are not uncommon. Great location for the second floor 'smart house', alarm, etc. panels also.

OK it makes sense now. With all of our 3:12 and 4:12 roofs, attics are far from inhabitable.
This is our typical attic framing. With all of the cross bracing it was hard to get 8' of clear space on the floor.

http://gfretwell.com/electrical/addition/smurf%20job.jpg

The next McMansion I get to, I'll get a shot of the 'attic' stairs, and the 'attic'.

John, and Greg,

Oh Yeah, this attic is large. It has 4 HVAC air handlers systems up there. You walk up into the attic. You also have stairs up and over two or three duct lines. I have to go back for a final inspection, when I do, I will also try to get some pictures for you guys.