Using 3 Wires for powered sensor

Reply

  #1  
Old 04-04-16, 05:25 PM
S
Member
Thread Starter
Join Date: Apr 2016
Location: United States
Posts: 2
Received 0 Votes 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:
Name:  dg85-connection.gif
Views: 3254
Size:  8.1 KBName:  yh-300-connection.gif
Views: 2421
Size:  12.7 KBName:  yh-300-connection-2.gif
Views: 1299
Size:  25.4 KB

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:Name:  2 powered sensors on 4 wires.jpg
Views: 4625
Size:  20.6 KB

Please let me know if I'm way off here.

Thanks a ton!
Jacob
 
Sponsored Links
  #2  
Old 04-04-16, 05:34 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,805
Received 1,194 Votes on 1,105 Posts
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.

Name:  2 powered sensors on 4 wires.jpg
Views: 1576
Size:  20.5 KB
 
  #3  
Old 04-04-16, 06:14 PM
S
Member
Thread Starter
Join Date: Apr 2016
Location: United States
Posts: 2
Received 0 Votes on 0 Posts
Thanks. I definitely realize my error in my drawing.

I plan on using an ELK M1 Gold panel. Does that sound any alarms (no pun intended) ?
 
  #4  
Old 04-04-16, 06:48 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,805
Received 1,194 Votes on 1,105 Posts
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.
 
  #5  
Old 04-04-16, 06:55 PM
C
Member
Join Date: Nov 2009
Location: Maryland, USA
Posts: 1,045
Received 38 Votes on 37 Posts
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.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: