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Explain relay based occupancy sensor #166290 07/17/07 10:58 AM
Joined: Feb 2004
Posts: 115
H
Haligan Offline OP
Member
This Leviton spec grade occupancy switch uses a relay. (ODS10) The listing warning specifically state that it is not to be used with a receptacle ie. plug-and-cord devices.
Technically speaking, what is the potential hazard here. I have an educated guess, but would like to really understand this.

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Re: Explain relay based occupancy sensor [Re: Haligan] #166291 07/17/07 11:06 AM
Joined: Mar 2007
Posts: 165
Retired_Helper Offline
Member
Haligan: I have no doubt that there are any number of folks on this post who could help you with this, but why not go directly to Leviton Customer Service at 1.800.824.3005? They made it, and provided the warning; they should be able to explain it.

Re: Explain relay based occupancy sensor [Re: Retired_Helper] #166293 07/17/07 11:15 AM
Joined: Sep 2001
Posts: 806
N
NJwirenut Offline
Member
The electronics in the switch are powered by a small (milliamps) current passing through the load, even when "off". Proper operation depends on the load having continuity at all times, which would not be the case with a receptacle with nothing plugged into it.

Re: Explain relay based occupancy sensor [Re: NJwirenut] #166301 07/17/07 02:28 PM
Joined: Dec 2000
Posts: 4,286
electure Offline
Member
The particular unit you have is rated 800 Watts @ 120 Volts incandescent.

This, and other control products with similar ratings would lose their smoke in short order if someone was to plug in ie: an 1800W blow dryer to a receptacle it controls.

That's why smile

I believe the electronics are operated between the hot and the equipment ground, rather than through the load. Here's a pic of one without an equipment grounding connection. (277V system)

[Linked Image]





Last edited by electure; 07/17/07 02:49 PM. Reason: to add pic
Re: Explain relay based occupancy sensor [Re: electure] #166304 07/17/07 03:59 PM
Joined: Sep 2001
Posts: 806
N
NJwirenut Offline
Member
Interesting, and kind of disturbing.

Does the unit operate properly without the equipment ground connection? Such a reading COULD be explained by RF bypass capacitors from line to ground, rather than using the ground as the return conductor for the electronics.

Would UL allow a manufacturer to use the ground as a neutral return, even at such presumably low current levels?

Re: Explain relay based occupancy sensor [Re: NJwirenut] #166309 07/17/07 05:51 PM
Joined: Dec 2000
Posts: 4,286
electure Offline
Member
The directions with them state that they will not work properly without the equipment grd connection. (and they won't).
They're UL listed and CSA certified

There were some (Wattstopper, I think) wall occ sensors made with a neutral pigtail, but I'm not sure if they're still producing them.





Re: Explain relay based occupancy sensor [Re: electure] #166356 07/18/07 08:44 PM
Joined: May 2003
Posts: 2,876
E
e57 Offline
Member
They still are.


Mark Heller
"Well - I oughta....." -Jackie Gleason
Re: Explain relay based occupancy sensor [Re: e57] #166358 07/18/07 09:19 PM
Joined: Feb 2003
Posts: 939
F
frenchelectrican Offline
Member
Scott now i can see why many peoples been yelping at my ear with the motion dectors and after i did see what you show us on the photo and i did rember very clear with the instructions it stated make sure you turn off the power if you will remove the devices but instering twist that one question i did not get chance to do this is how much current leaking going thru the device like this ??

the reason why i want to prepared in case if i ran into the AFCI crap you know what i mean

thanks.

Merci , Marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)


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