Door/Window contacts - Types and Brands

[Del91574]

Not sure I understand what you mean. You want to see a pos and neg at the panel on that diagram (that really doesn't make a difference)?

BSR, respectfully,

It makes a HUGE difference where the EOLR is located within a circuit as well as which panel leg it's tied to. Since we're in NA, almost every commercially available panel shares a common negative. Not to hop off topic, but a large prestigious university here had panels called Logiplex(es) installed, and on a single circuit pair, there were multiple EOLR's (similar to zone doubling) all color coded: red, blue, yellow. (R, B, Y for discussion)

In my case, install the EOLR on the wrong side of the loop then take a small circuit fault, a high resistance splice....that could mean on top of the R and B EOLR's, if you had an open or fault condition, the panel might not see the Y EOLR or wiring fault. This is just an example, but factor in the length of wiring and then a couple of splice points....install a surface contact on a steel or aluminum extrusion door, with the insulation getting mucked up, ground loops were possible and they did happen....how do I know this? Try explaining to a director of IT and technology why a door can be left wide open and the IDS or ACS be able to function as normal.

It's part of the reason why true fire alarm systems supervise and monitor for ground faults, which comes down in scope to be wire and circuit integrity beyond what the EOLR supervision can supply.

 

[BraveSirRobbin]

I'm not saying put the resistor at the panel, I was saying does he want to see a 'pos' and 'neg' nomenclature 'at the panel'.

What others are saying is it makes a difference if you put the EOL at the pos or neg lead 'at the sensor'. I say, it does not make a difference in a regular door or window sensor.

Again, I just don't use them in doors or windows on a residential install.

 

[Del91574]

BSR, again, respectively, you are incorrect, it makes a HUGE difference on any circuit connected to the panel, no matter what the type, where it's connected. Placement at the panel was not mentioned. I mentioned NA panels and common negative, as that is what exists on the market here, however I have seen and worked on panels in the past that shared a common positive with isolated COM/NEG on zones, but those would be considered by myself to be exceptionally rare examples, that I am not mentioning here.

The EOLR, if installed, needs to be at the last device's negative connection before the home run back to the panel. For simplicity's sake, I'm only talking about a single circuit pair and contact (or relay). If the cabling has a ground present and the EOLR is installed on the pos. side of the loop, the panel may never see the contact (or relay) change state. If you have the EOLR on the neg side, the ground would negate the EOLR, generating a trouble or open circuit.

While I can't comment on other's installation methods, it's part of the reason why I wire my powered devices as 3 wire units with the EOLR installed at them.

The best I can say is bench test a panel with an EOLR on the POS and install a contact downstream, then add a ground fault to the cabling bridging to COM. You'll never see the contact change states as far as the system is concerned.

 

[gizzmo]

Think of it this way, every panel has a diagram on the door that shows all contacts on the positive side of the circuit. Could be a coincidence but I doubt it.

Sent from my Galaxy Nexus

 

[BraveSirRobbin]

There are several discussions that always develop interesting conversations on our forums; EOL and 120 VAC smoke detector threads!

As for this discussion, there is an EXCELLENT FAQ written by Sandpiper on EOL resistors. If you look at paragraph #32 you will see the only time you need to even consider polarity is when you are using a shielded cable (with the shield tied back to an earth ground) or the small possibility that a metal door or window frame is somehow tied to earth ground and the cable can come in contact with it if knicked (highly unlikely).

Myself, I'm going to do what I usually do and give my advice, then watch the continued discussions.

 

[gizzmo]

There are several discussions that always go over the top on our forums, but two of my pet peeves are EOL and 120 VAC smoke detector threads.

As for this discussion, there is an EXCELLENT FAQ written by Sandpiper on EOL resistors. If you look at paragraph #32 you will see the only time you need to even consider polarity is when you are using a shielded cable (with the shield tied back to an earth ground) or the small possibility that a metal door or window frame is somehow tied to earth ground and the cable can come in contact with it if knicked (highly unlikely).

Myself, I'm going to do what I usually do and give my advice, then watch the continued discussions.

I am not going for a pissing contest here and I am sorry if your offended. If you think that loop or circuit polarity in relation to EOLR placement and contacts makes no difference you are misinformed, regardless of your source. It seems that you are growing weary of being lectured on the correct method to connect 120V smoke alarms and contacts to an alarm system. Once again do anything you want to do but if you or an active thread seeks input or advice, I will do my best to give to all who care to read, my best advice.

Sent from my Galaxy Nexus

 

[Del91574]

BSR, in this case, while you may be adamant it's not true, but your FAQ and yourself are incorrect and I emplore you to try a little science experiment to tell me that myself and Gizzmo are wrong.

As stated, look at almost any panel manufacturer's schematic (Napco has a few that are incorrect out there) and tell me that we're wrong, but it's not a coincidence. Polarity connecting a contact or relay doesn't need to be observed, however in locating the EOLR properly, it does.

Shielded cabling is not relevant to a ground loop, which may or may not exist whether or not a panel and/or wiring is connected to EG. In this case a ground loop would be possible between the COM/NEG of the alarm panel and any field wiring's COM or NEG connection, not just EG.

Install a 4/22 for a motion with a zone conductor shorting or resistive faulting to the panel COM/NEG and then install an EOLR and tell me it's not going to make a difference. Another example would be a surface contact installed on a aluminum or steel door with shavings from drilling causing a short via the jamb and a conductor, not through EG. If you've never seen it happen, then you'll take the "unlikely" standpoint as you see it, but in the case of real world, it happens more often than one would care to admit to, because as "pros" or "gurus" we think our wiring or installation methods and practices are infalable.

 

[BraveSirRobbin]

Thanks for the input all:

I'll look into it and do whatever is best for our forum members (as that is paramount)!

I guess I'm just missing the old 'hobbyist' forums this once used to be...

 

[apostolakisl]

Just for shits and giggles, I closed one of my Elk zones to my house's ground, and indeed it created a ground loop and the zone went to zero volts. However, as is the case for most residential settings, I don't have any steel frame doors. So, I couldn't test to see if a steel door framed door is contiguous with ground.

So, I would say, since it is just as easy to put the EOLR on the hot side of the contact as it is to put it on the neutral side, you might just as well put it on the neutral. But, I certainly see BSR's point. You would probably need to install 1,000,000 residential systems before an eolr installed on the neutral side of the last contact before you ever saw your first problem. Especially if you do it like I do, which is to use the screw down terminal type contact and put the eolr directly into the terminal. There just isn't any room for something to get in there and short to earth.

EDIT:

Just out of curiosity, does closing your zones to the house ground instead of the dedicated ground back to the panel run any risk of damaging the panel?

The thought that comes to mind, what if you only ran one zone to some location, and then decided you wanted two. But running a wire back to the panel would be next to impossible. So instead of running a new wire, you re-purpose the neutral to hot on a different zone and use the house ground as the neutral for the two zones.

 

[ecborgoyn]

I very sorry that I provoked the EOLR advocacy...... But for the record I will be installing single EOLR's on the 'negative' side of my 'closed loop' door and window contact circuits. A small amount of work and no additional cost (Elk provided resistors) for a more robust system.

 

[Del91574]

A few other people are missing what a ground loop can consist of. While EG is entirely within the realm, there's other ground loops that can (and do) occur with wiring, enclosures and the hardware, not just a straight EG ground fault.

In my case, I've seen, for people to view the contact style, a Honeywell 7939 (or GRI 29, Sentrol 1085) contact have metal filings bridge on the inside of the trim piece between an EOLR, causing the ground fault. More common than you'd care to believe. I've also seen similar on recessed contacts installed in steel clad wood doors, the biggest offender being Thermatrue doors, they have a screw that is driven up through the sill into the mullion where the contact typically needs to sit, so a hole saw is called out, afterlwards being followed by a bellhanger bit through the aluminum sill....the worst tends to happen with unjacketed cables, but some of the "discount" cables that come in the plastic packs are pretty thin also.

In the case of using the house's ground as a return path, the M1 isn't connected to EG, so you're effectively grounding you panel to EG, which is NOT recommended by Elk, though no damage should result. You would not get a reliable connection using the EG as a return path, not to mention introducing different voltage potentials to the system. It'll work in "textbook armchair QB'ing" but that's the only place you'd see it function.

 

[gizzmo]

Perhaps a true story would help to show why I am so rigid on where to place the EOL or have one at all.

About 25 years ago I was working with a 16 zone system that was partitioned to serve two tenants of a building. Back then I saw resistors as more in the way and decided that if I am going to install them in the panel anyway that I would just program the zone as normally closed and save room. The landlord who was one of the tenants too, called to say the other tenant was having false alarms. The false alarms happened intermittently but only when he reached an exact point in his side of the building the other tenants partition back door would false. I set his system and opened his door to start the entry tone and proceeded to the keypad with no false alarm. This was repeated several times until I reached the "magic" spot and the rear door of the joining space went off. Here is the reason why it was intermittent. There were two grounds on the system, one at the landlords front door and one at the tenants rear door. If the landlords front door was closed prior to the motion in the office area detecting movement on the way to the keypad, no alarm. If the door hadn't finished closing and the motion activated the rear door on the other tenant would go into alarm.

Don't forget that the closest ground to your wire is in the same jacket. I wont try to change everyone's method of installation but I can say where is the good better and best locations are:
Good = In the panel on the common side of the circuit
Better = at the end of the circuit.
Best = No daisy chain but a continuous loop going from device to device with relays or contacts only connected to the red wires. Black wires connect only to other black wires and stop only at the resistor which is then connected to the last device.This will mirror the schematic on the panel door. Obviously if the device is a powered type you can use the yellow for + and the green for - .
Just for the record, I am only referring to burglary zones in this example.

 

[gizzmo]

Just for shits and giggles, I closed one of my Elk zones to my house's ground, and indeed it created a ground loop and the zone went to zero volts. However, as is the case for most residential settings, I don't have any steel frame doors. So, I couldn't test to see if a steel door framed door is contiguous with ground.

So, I would say, since it is just as easy to put the EOLR on the hot side of the contact as it is to put it on the neutral side, you might just as well put it on the neutral. But, I certainly see BSR's point. You would probably need to install 1,000,000 residential systems before an eolr installed on the neutral side of the last contact before you ever saw your first problem. Especially if you do it like I do, which is to use the screw down terminal type contact and put the eolr directly into the terminal. There just isn't any room for something to get in there and short to earth.

EDIT:

Just out of curiosity, does closing your zones to the house ground instead of the dedicated ground back to the panel run any risk of damaging the panel?

The thought that comes to mind, what if you only ran one zone to some location, and then decided you wanted two. But running a wire back to the panel would be next to impossible. So instead of running a new wire, you re-purpose the neutral to hot on a different zone and use the house ground as the neutral for the two zones.

I have used the negative power wire in motions and keypads when I had a bad or broken conductor. If you ever need do this it really helps to leave a note for the next service person. it can blow their mind to see a solitary wire on a zone. As to connecting to the house ground thing I wouldn't touch it. Lightning bolts feed on that stuff.

 

[Del91574]

I have used the negative power wire in motions and keypads when I had a bad or broken conductor. If you ever need do this it really helps to leave a note for the next service person. it can blow their mind to see a solitary wire on a zone. As to connecting to the house ground thing I wouldn't touch it. Lightning bolts feed on that stuff.

I tend to wire my powered devices as a 3 wire across the board, jumping the EOLR between the C (or relay pole) and the power feed's negative. Saves a chicklet, supervises the zone and a wiring fault is just as easy to find (detector has power, then problem is with circuit wire or EOLR jumper). The panels I gravitate towards run a high loop voltage compared to other manufacturers, so I haven't had any issues with "dirty" splices, even though I try to always use the filled chicklets.

 

[gizzmo]

The filled beans keep people from chewing on them too.

Sent from my Galaxy Nexus