Motion sensor switch, and GFCI... problem!

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Old 07-08-08, 08:49 AM
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Motion sensor switch, and GFCI... problem!

When I built my HT room, I had a motion sensor wired and located in such a way that when someone walked near the riser step, it would trigger the steplight to turn on.

The steplight is a standard 120V fixture. Because I want the light to be very dim, I ended up using a 7.5W bulb (yes, they do have large bulbs with standard sockets in 7.5W rating!).

The problem is that apparently, the motion sensor needs a larger load to function correctly. It is currently working only half the time, before it starts blinking on/off like crazy and eventually kills the bulb.

Well, I found a new motion sensor switch manufactured by RAB which does NOT have a minimum load requirement. I tested it first in the garage switch (quicker access) and it worked perfectly with a 7.5W bulb.

HOWEVER! When I wired it in the HT room, it immediately pops the GFCI that is in the same circuit. Why?! The old sensor had no issues in this same spot. Can anyone provide some guidance on what may be happenning here? I know I am wiring the new switch properly, just as I did in the garage!

EDIT: In a live test (risky, I know!), the GFCI jumps as soon as I connect the ground copper cable, which I connected last.
 
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Old 07-08-08, 09:00 AM
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Originally Posted by gnolivos View Post
When I wired it in the HT room, it immediately pops the GFCI that is in the same circuit. Why?!
The new sensor is using the ground wire as a neutral wire by dumping its current on the ground wire instead of completing the circuit through the load like your old sensor did. The specific purpose of the GFCI is to protect against any current going to ground so it detects this situation and trips.

Is the new sensor supposed to be wired to a neutral? Do you have a link to the installation schematic?
 
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Old 07-08-08, 09:06 AM
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Can you run the model number of the RAB motion sensor ??

Once we know the model number we can go from there and yes Ibpooks is right some of the motion sensor used the ground as netural which I am not too crazy with it { don't ask me why I know this due I done alot of commercal verison which they ran 277 volts and got nailed from that }

Most good motion sensor will have true white netual wire in there so it will function properly.

Merci,Marc
 
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Old 07-08-08, 11:33 AM
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Thanks guys, you are on to something!

here it is:

LOS800 from RAB:
http://www.rabweb.com/product_detail...ct=LOS800W/120

Relevant info:
 

Last edited by gnolivos; 07-08-08 at 01:32 PM.
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Old 07-08-08, 01:43 PM
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Update:

I called RAB tech support. They confirm the 'issue', but state that I should wire this differently in the presence of a GFCI.

I currently have the switch's white wire connected to the copper ground on the wall. I understand they want me to connect the white wire to Neutral. So, does this mean I don't connect to the copper ground at all?

In summary, I have coming from the wall:
-1 black
-2 black twisted together
-1 copper

Coming from the switch:
-1 white
-1 black
-1 red

So, what are you guys guessing I need to wire to what? Sorry, this is making little sense to me. I've wired many switches in the past, never quite this way...!
 
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Old 07-08-08, 02:20 PM
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Originally Posted by gnolivos View Post
Update:


In summary, I have coming from the wall:
-1 black
-2 black twisted together
-1 copper
If you don't mind please do expain little more on this one ??

I know you say two black wire twisted together but where is the white wire in that box ?? is there two white wire in there or not ??

That why I want to clear up this detail before we get into switch loop which they are somehow diffrent so just want to verify it first.

Merci,Marc
 
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Old 07-08-08, 02:27 PM
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Oh I think I see where this is going. Yes, there are white wires attached to each other in the box. I never connected anything to them (not with the OLD or NEW switches).
 
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Old 07-08-08, 02:41 PM
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.,, Bingo.,


Now that is the place to hook up the white wire for the motion sensor to work and the red wire go to the luminaire while the black wire is hot lead

Once you get this hook up right it will function right.

Merci,Marc
 
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Old 07-08-08, 03:08 PM
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french:

Thanks! So, the copper wire from the box DOES NOT GET CONNECTED?

If this is the case, then will the GFCI properly trigger if there is a short at the light fixture in question? (remember, it is a step light, and near floor level! The reason I put a GFCI in the first place!)
 
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Old 07-08-08, 03:18 PM
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Originally Posted by gnolivos View Post
french:

Thanks! So, the copper wire from the box DOES NOT GET CONNECTED?

If this is the case, then will the GFCI properly trigger if there is a short at the light fixture in question? (remember, it is a step light, and near floor level! The reason I put a GFCI in the first place!)

If you have metal box the bare copper wire must be bonded to the box However .,, If you have plastic box the ground wire will be tied together with green wire or green screw if they have it.

For the luminaire on the stairway not always have to be GFCI'ed at all depending on what room it serve.{ If your area reqired a AFCI then you have to do it }

If the luminiare shorted out for some reason it will trip the breaker not the GFCI { some case it will trip the GFCI first before the breaker } but if the netural wire touch with bare copper wire { ground } it will automatically trip the GFCI pretty fast.

Merci,Marc
 
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Old 07-08-08, 03:27 PM
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Thanks French.

It is a plastic box, and there is no green wire from the switch. Also, no green screw on the switch. I guess I leave the ground wire 'open' in this case?

Will this in any way affect the proper function of the GFCI in that circuit?

Thanks for all your help, I will wire this tonight.
 
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Old 07-08-08, 03:42 PM
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That kinda pretty rare to see the motion switch don't have green wire or green screw at all.

Yes you can leave the ground wire in the box { do not cut the ground wire off at all }

To affect the GFCI circuit with plastic box useally not unless the luminaire have netual / green wire touching as well.

Ok Let us know how you come out with it.

Merci,Marc
 
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Old 07-09-08, 08:39 AM
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Thank you french. I wired as you said, and now it all works correctly! I had to leave the copper/ground from the box without connecting to the switch, since there is no green wire or green screw.

Thanks for all your help!!!!


Originally Posted by french277V View Post
.,, Bingo.,
Now that is the place to hook up the white wire for the motion sensor to work and the red wire go to the luminaire while the black wire is hot lead

Once you get this hook up right it will function right.

Merci,Marc
 
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