Occupancy Sensor

[Machiavelli999]

Wattstopper offers several line voltage occupancy sensors that can control independent circuits. For example this one:

http://www.wattstopper.com/products...-and-vacancy-sensors/pw-302.aspx#.Uo1S_eIjPMA

Any NEC issues with one sensor controlling a 277V and a 120V circuit. My electrician seems to think there are code issues with a 277V & 120V circuit in the same box but I see both of these circuits being under 300V so within the standard insulation rating of most cables.

 

[Gregg Harris]

Wattstopper offers several line voltage occupancy sensors that can control independent circuits. For example this one:

http://www.wattstopper.com/products...-and-vacancy-sensors/pw-302.aspx#.Uo1S_eIjPMA

Any NEC issues with one sensor controlling a 277V and a 120V circuit. My electrician seems to think there are code issues with a 277V & 120V circuit in the same box but I see both of these circuits being under 300V so within the standard insulation rating of most cables.

300.3(C)(1) tells you yes

 

[qcroanoke]

300.3(C)(1) tells you yes

You can use a barrier between them and be ok.

 

[Machiavelli999]

Yes what? There are issues?

I actually pointed him to NEC 300.3(C)(1). It seems to say that if I have a 277V & 120V circuit in same box, it is permitted as long as the cable insulation of all cables is 300V. Am I wrong?

 

[GoldDigger]

Yes what? There are issues?

I actually pointed him to NEC 300.3(C)(1). It seems to say that if I have a 277V & 120V circuit in same box, it is permitted as long as the cable insulation of all cables is 300V. Am I wrong?

However, I believe that you still cannot have power of two different voltages going to a single-yoke device. The rationale, I suspect, is that you should not have to trace and turn off two different circuits, almost certainly in two different panels, before it is safe to remove and work on that device.
The specs for the unit you listed show that the occupancy sensor can only turn on one of the two load relays, but can turn off both when the timer expires. Very interesting.
Also, since it operates only one side automatically, it will switch only one conductor of a line-to-line load. And to control two load circuits with different line inputs (hot) requires two interconnected devices, either next to each other or in different locations in the room.

 

[Gregg Harris]

300.3(C)(1) tells you yes

 

[GoldDigger]

300.3(C)(1) tells you yes

And 210.7 tells the OP no.

Multiple Branch Circuits
Where two or more branch circuits supply devices or equipment on the same yoke, a means to simultaneously disconnect the ungrounded conductors supplying those devices shall be provided at the point at which the branch circuits originate

Not easy to do when the 120V and 277V circuits originate in different panels! Very large handle tie.
But I guess you could go through two snap switches on separate yokes with a handle tie just to provide the disconnect.
Not to mention the OP's more serious problem that the device he is looking at cannot take more than one input source at a time. It can control two separate outputs from that input though.

 

[Machiavelli999]

And 210.7 tells the OP no.

Not easy to do when the 120V and 277V circuits originate in different panels! Very large handle tie.
But I guess you could go through two snap switches on separate yokes with a handle tie just to provide the disconnect.
Not to mention the OP's more serious problem that the device he is looking at cannot take more than one input source at a time. It can control two separate outputs from that input though.

Hmm...so seems like power packs are the only way to go

 

[qcroanoke]

You can use a barrier between them and be ok.

I guess I should have looked at the PDF before posting..
I did not realize you were talking about being on the same yoke.

 

[Machiavelli999]

Looking at this further, it still confuses me. Because 210.7 seems to say that two circuits irrespective of voltage cannot go into the same device if there is no means to simultaneously disconnect them. If I interpret that the way we seem to be interpreting this in this thread, it would imply that basically all of the Wattstopper devices that allow for control of two independent circuits are not compliant with NEC unless we have both the circuits coming from the same panel and with a 2 pole breaker to control both circuits simultaneously.

I thought that the issue was 120V & 277V circuits going into the same device, but reading 210.7 seems to raise other issues.

 

[GoldDigger]

Look very carefully at the Wattstopper diagrams in the specifications and I think you will agree that although they can control two output circuits each device has only one power input.
To control two loads fed from two different branches requires two interconnected devices anyway.


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