Using 3 Wires for powered sensor
#1
Member
Thread Starter
Join Date: Apr 2016
Location: United States
Posts: 2
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Using 3 Wires for powered sensor
Hello All,
Is there a problem to jump the common terminal of a zone (Z- or COM) with the Aux Power Negative terminal (- or GND)?
As I see it, this would essentially allow 12V of power (powering the sensor) to return to the panel to the Zone Common instead of the AUX 12V GND. Is this bad for the panel (I'm not an electrical engineer)? If this is OK, should the GND(-) and COM(Z-) terminals be jumped at the panel to provide a return path for the 12V back to the transformer?
I saw this done on a certain website, as can be seen from the pictures below:
I see this as having 2 applications. The first being if 1 wire in a 4 wire powered sensor install is cut and cannot be repaired, then it would seem that you can run power and alarm sense over 3 wires instead of 4.
The second application would be to run 2 separate powered sensors off of one 4 wire (18/4) cable.
Red - Would power both sensors
Black - Would be connected to both sensors' COM(Z-) terminals as well as both sensors' GND(-) terminals.
Green - Would connect to NC on one sensor
Yellow - Would connect to NC on the second sensor.
If this is possible, I believe it would allow for the use of a combo PIR/Glassbreak sensor like the BV-500GB (Bravo® 5 360° Ceiling-Mount PIR Motion Detectors - BV-500GB, BV-501GB, BV-502GB Security Products | DSC) (manual here: http://www.alarmhow.net/manuals/DSC/...20Detector.pdf) with only 4 wires and not 5 or 6.
Like this pic that I just drew up on the BV-500GB Manual:
Please let me know if I'm way off here.
Thanks a ton!
Jacob
Is there a problem to jump the common terminal of a zone (Z- or COM) with the Aux Power Negative terminal (- or GND)?
As I see it, this would essentially allow 12V of power (powering the sensor) to return to the panel to the Zone Common instead of the AUX 12V GND. Is this bad for the panel (I'm not an electrical engineer)? If this is OK, should the GND(-) and COM(Z-) terminals be jumped at the panel to provide a return path for the 12V back to the transformer?
I saw this done on a certain website, as can be seen from the pictures below:
I see this as having 2 applications. The first being if 1 wire in a 4 wire powered sensor install is cut and cannot be repaired, then it would seem that you can run power and alarm sense over 3 wires instead of 4.
The second application would be to run 2 separate powered sensors off of one 4 wire (18/4) cable.
Red - Would power both sensors
Black - Would be connected to both sensors' COM(Z-) terminals as well as both sensors' GND(-) terminals.
Green - Would connect to NC on one sensor
Yellow - Would connect to NC on the second sensor.
If this is possible, I believe it would allow for the use of a combo PIR/Glassbreak sensor like the BV-500GB (Bravo® 5 360° Ceiling-Mount PIR Motion Detectors - BV-500GB, BV-501GB, BV-502GB Security Products | DSC) (manual here: http://www.alarmhow.net/manuals/DSC/...20Detector.pdf) with only 4 wires and not 5 or 6.
Like this pic that I just drew up on the BV-500GB Manual:
Please let me know if I'm way off here.
Thanks a ton!
Jacob
#2
Welcome to the forums.
Although it isn't typically how zones are set up. You can get away with it in most panels as the zone common terminal is the same as negative aux power.
I made a correction to your diagram if you were planning to use the tamper feature.
Although it isn't typically how zones are set up. You can get away with it in most panels as the zone common terminal is the same as negative aux power.
I made a correction to your diagram if you were planning to use the tamper feature.
#4
I had to look that part up. It is not something I have installed before so I can't offer you any first hand advice on it. No up-to-the-minute alarming news.
Hang tight. Others will stop thru and will offer help if they've used it before.
Hang tight. Others will stop thru and will offer help if they've used it before.
#5
Member
I actually did this in 3 bedrooms for a personal customer/friend who had had new windows installed and lost the wires in the wall. She didn't want to breach (drill) the window frames and invalidate the warranty, so I ran PIRs and GBs in each bedroom on one quad cable each. They're casement windows so they aren't going to be force-opened without breaking.
That was a few years ago and there have been no problems with it.
That was a few years ago and there have been no problems with it.