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Home > Archive > Electrical Engineering > June 2006 > Are damper motors required to have a disconnect?
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Are damper motors required to have a disconnect?
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| electrician@electrician2.com 2006-06-24, 3:25 am |
| The new Washington State rule says no. So where in the NEC does it say
no?
Here is the Washington explanation:
"Do HVAC Damper Actuators Need Motor Disconnecting Means Per NEC
Article 430?
No, an actuator is considered a component of the damper assembly and is
not subject to the
disconnect requirements of NEC 430.101. Though often called by other
names such as damper motors, damper operators, or motor packs, damper
actuator is the appropriate term. A damper actuator is not a motor
subject to NEC Article 430. Dampers are available with a wide variety
of actuators installed. Some dampers are shipped without actuators and
intended for installation of an actuator in the field after the damper
has been mounted in the
HVAC mechanical duct system. All actuators on UL classified Smoke and
combination Fire Smoke Dampers must be furnished and installed by the
damper manufacturer at the time the damper is manufactured. Regardless
of the specific application, all dampers should be installed in
accordance with the installation instructions for the damper assembly."
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| Paul Hovnanian P.E. 2006-06-24, 5:25 pm |
| electrician@electrician2.com wrote:
>
> The new Washington State rule says no. So where in the NEC does it say
> no?
I think the NEC permits it under the condition that a damper is a
component of an HVAC system with a single controller. The controller
disconnect may serve as the disconnecting means for multiple motors (and
other devices) under certain conditions. One of these would be that the
disconnect would have to be lockable if it is not within sight of all
equipment being disconnected. I'd look at 430.87 and 430.112 exceptions.
If you think about it, this is preferable to an individual disconnect
for each damper motor. In the case of a fire damper, the damper motor
can't be left inoperative while associated fans are still powered.
> Here is the Washington explanation:
>
> "Do HVAC Damper Actuators Need Motor Disconnecting Means Per NEC
> Article 430?
>
> No, an actuator is considered a component of the damper assembly and is
> not subject to the
> disconnect requirements of NEC 430.101. Though often called by other
> names such as damper motors, damper operators, or motor packs, damper
> actuator is the appropriate term. A damper actuator is not a motor
> subject to NEC Article 430. Dampers are available with a wide variety
> of actuators installed. Some dampers are shipped without actuators and
> intended for installation of an actuator in the field after the damper
> has been mounted in the
> HVAC mechanical duct system. All actuators on UL classified Smoke and
> combination Fire Smoke Dampers must be furnished and installed by the
> damper manufacturer at the time the damper is manufactured. Regardless
> of the specific application, all dampers should be installed in
> accordance with the installation instructions for the damper assembly."
Where did you get this interpretation? It doesn't seem to explain the
situation very clearly.
--
Paul Hovnanian mailto:Paul@Hovnanian.com
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Due to recent budget cuts, the light at the end of the tunnel has
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