Quick question regarding Elk M1 pre-wire.

[chazno]

I'm sure I could have found this if I searched enough but i need an answer quick as walls are about to go up. Please accept my apologies, but I'm checking up on an installer who does not usually install ELK.

In looking at the manual I noticed the keypads recommend cat5 or 6, my house was wired with 4. I'm having them correct that, but is there anything else I should look at that differs from low end cheapo systems that this installer normally puts in? The system on consists of door contacts, glass breaks and motions.

 

[chazno]

guess I can't edit- I meant 4 conductor as opposed to cat 5 or 6.

 

[apostolakisl]

Actually 4 wire is fine, but it needs to be done differently. Daisy chained from one to the next with a terminating resistor at the end.

Cat5 lets you home run each keypad and use the m1dbh for quick and clean "daisy chain" equivalent. Since you are having cat5 now, make sure they are home runs. The benefit will be in ease of installation and future mods whatever that may bring. Possibly less chance of interference with cat5/6 twisted pairs, but probably won't matter.

Also make sure they don't run the cat5 parrallel to 120v wires, you need to keep them a foot away if running parrallel. Cross at 90.

Hard to say anything else without knowing what is going on. I guess it is all about the wire for doors/windows, how they are grouping the things (one wire for a whole room of windows or home running each window or whatever). The quality of the door/window conatacts. The quality of the motion's (I would also suggest cat5 for them).

 

[Del91574]

4 conductor is no issue, as Elk makes retrofit hubs to split up the 485, negating the need for a daisy chained data run.

I would, contrary to the other advice, not use Category cables for anything other than data, it's too light and fragile for most purposes, as well as a heck of a lot more difficult to work with in the case of a contact or powered device. The advice about the separation and crossing HV cables is somewhat of a wives tale, and most cases, does not affect the functionality or reliability....and in the case of ethernet, there's other factors involved.

 

[video321]

I'd have them add the Catx, but keep the existing 4-conductor there.
It gives you the option of using the lower gauge wire initially plus have the ability to add an IP touch panel later on.

 

[apostolakisl]

"irregardless" of what Dell says, it is not a an old wives tail that EM inteference can get from 120v lines to CAT5 or other data cable. Especially if there is high amp draw on that line. Most wires aren't pulling current most of the time and mostly they don't pull that much, so you probably won't have a problem. But don't be stupid and take the risk. It would be impossible to figure it out and solve it later. Absolutely impossible. The walls are open, do it right.

If you want to use the 4 wire, do it like someone who is pre-wiring would do it, not a retrofit job. Again it would be just plain stupid to be pre-wiring just to add a retrofit hub. The walls are open, do it right. But Elk is quite fond of using the cat5 wire and provides the dbh for a wonderful, clean, installation with great future versatility.

If the 4 wire is already there, I agree with the comment to leave it there. You probably won't ever need it, but what the heck, it isn't causing any problems and pulling it out just costs more money.

 

[wuench]

I kind of wish I would've used 4-wire instead of Cat5 for my runs using the "retrofit" hub. 4 wire takes up a lot less space and that Cat5 is taking up most of the space in my can and it is a pain to terminate at the keypad end, if Elk had thought to put an RJ45 jack on their keypads it would have been nicer. I think the 4 wire (with hub) solution would be ok as long as you didn't have need for extra pairs off the cat5 for the keypad input/ouputs or speakers.

 

[apostolakisl]

"if Elk had thought to put an RJ45 jack on their keypads it would have been nicer."

I would have loved that since I used cat5. But if you had wanted to use 4 wire you would have needed an adapter.

Personaly I think screw downs would have been best. It accomodates many gauges of wire and is quick and secure. Elk certainly put them everywhere else, why not there I don't know. It is also faster to do screw downs then to put an rj45 plug on the wire.

But if your using 4-wire, why would you want a retrofit hub when you could just daisy chain them as shown in the manual. If you want the least stuff in the box, that gives you just a single wire. Also, you don't have to mount the dbh unit inside the can. It could be located somewhere else and just bring the single 4 wire connection into the box from the dbh.

CAT5 gives you the option of using other pairs for other uses, but mostly it leaves the door open to use the cat5 to carry IP if you wanted to wall mount any number of IP based devices.

 

[wuench]

Screw downs would have been nice, or even both options. It's been so long since I have looked at the back of the keypad I can't remember what it has, but I do remember my termination being a mess. I haven't acutally used the retrofit hub before but I figured it would serve the same purpose at the Cat5 hub as a way to keep the wiring neat in the can. But for me that ship has sailed, I am on Cat5 bus now, my biggest issue is that I didn't account for all the cat5 filling up my raceways in my can. I could probably move to a little deeper raceways someday if i need to add more devices....

 

[Neurorad]

Agreed, add the catx, but don't remove the 22/4, for the keypad locations.

And, wire for several speakers. Many people like mounting the single speaker behind the KP2. I think an 18/2 would serve this purpose well.

Also, I suggest wiring the overhead garage doors, with catx, 22/4, or 18/2.

 

[apostolakisl]

Neurorad is on the mark there. Don't forget the garage doors. And make sure that if you have multiple doors to wire each one on its own zone. I didn't and then had to do a retrofit job when later I decided to automate the doors.

Since overhead doors have RF it isn't the end of the world if you don't run wires from Elk to the controllers, but since your walls are open, do it!

 

[Del91574]

Lou, you misread my statement regarding data/ethernet and crossing HV cabling, so I'd suggest a re-read, and you're misinterpreting what a retrofit hub actually does.

A retrofit hub simply allows more branches to the 485 bus to be installed, and on a single board, allows you to have 4 supervised and terminated branches per board. It has nothing to do with a right or wrong way to install the system, corner cutting or similar. In many cases, it would be a preferred way to go for wiring an extended bus to outbuildings or similar, as a single twisted pair, or shielded twisted pair is the only thing needed besides a common negative for the field wiring to the 485 devices, provided a local power supply is installed. Cuts down on the possibility of interference and inductance,as well as data reflections, which was your concern stated prior.

IMHO, a proper way to install the system would be to pull 8 conductors to each keypad, UTP 22 AWG, and hardwire daisy chaining within the panel, because honestly, the normal hub only maintains the amount of untwist on a properly terminated RJ45, and moving a terminating resistor/jumper on a system isn't a common occurance.

I'd have mixed feelings regarding screw terminals or an RJ jack on a KP. Many times people don't get the cables to properly clamp in elevator terminal blocks and RJ's have their own host of issues with the spring terminals. Since stranded is also used in the trade, that really leaves out IDC/punchdowns, so you're left with pigtailing, while screw terminals would IMHO be easier.

 

[apostolakisl]

Dell,

The only way to interpret your statement about HV/data cable "The advice about the separation and crossing HV cables is somewhat of a [old] wives tale, and most cases, does not affect the functionality or reliability" would imply that you should not bother following the advice.

Perhaps if following the advice were very expensive or very complex, it might be worth taking your chances. But it almost never is expensive or complex. And as I mentioned, since most home hv lines are carring few if any amps most of the time, you get away with it almost all the time. But, it would be just silly not to spend the extra . . .well pretty much extra nothing to separate them.

I do understand how the retrofit hubs work. Elk says no more than 2 parrallel data lines, the hub expands that. But if you are putting in a new system with new wires, you can do all the same things that a hub would allow without a hub. Why spend the extra money and have the extra stuff when it isn't necessary?

Regarding not use cat5 for your wires you commented that "it's too light and fragile for most purposes". Elk has spec'd the system for running cat5 to the KPs. So unles you need too exceed those specs (which are quite generous) it is not too light. Being too "fragile", well, I don't know how to interpret that. Do you have data comparing cat5 to some other type of wire as far as cut resistance, tensile strength, radius arc, and repeat bend metal fatigue breakage? I am sure the data exists somewhere. I don't have the data, but here are my guesses: cat5 wins radius, cat5 wins repeat bend/metal fatigue, toss up on tensile strength, and loses on cut resistance.

But in short, I think none of that matters because I think there are very few cases where the wire is subjected to something in the middle zone between failure points for the two different wires. In other words, when the plumber drills a hole through your wire, or the drywaller runs a screw through your wire, both fail.