Cat5e and Power Question

[fas 0]

An upcoming job requires 8 cameras with no economical way to run cabling. Cat5e is present however in all proposed camera locations. I have always used nothing but siamese cable for power and video, but here it is not possible. My question is, will I be able to successfully use the existing cat5e for power? Basically what I am asking is has anyone had luck with this type of setup in the past? The runs will be no longer than 300-400 feet. Here is the camera I will be using:

 

http://www.cnbusa.com/en/html/product/product.php?inc=spe&seqx_prod=1066#p_v1

 

If I use one pair for video, and 3 pairs for power, will this work and be stable?

 

I see that using 3 pairs is somewhat equivalent to 18ga wire, but I have never done this, so that is why I am asking.

[Soundy 1]

That camera is super-low current draw, so you should be okay. Even at 12VDC, losses should be only 0.1V, although just to be safe, I'd use 24VAC for the power.

[fas 0]

I know this has been gone over ad infinitum on this forum, but what would be the advantage of using anything but cat5e for a job like this in the future if voltage losses are so minimal? Siamese is bulkier, more expensive, and harder to install in tighter spaces. From what I can gather using 3 pairs of cat5e for power is essentially 18ga anyway. Using the cat5e also plans for future ip camera use. So why do most recommend against using cat5e for power?

[Soundy 1]

The voltage drop DOES start to become an issue with higher current draw, especially when you start getting into IR cameras, which seem to be overly popular. For example, once you get up to a half-amp draw, you lose nearly a full volt at 12VDC.

[fas 0]

I understand, but if you are using 24v and distances are in the 300-400ft range or less, even at .5a in theory you should still be fine. I just don't understand why this is not deemed "professional". If you were to do a job like I described above, would you use anything but cat5e, regardless of the situation?

[Soundy 1]

Probably not. As you note, it's cheaper that running two separate or Siamese wires, it's easier to work with, it future-proofs you, and it means you only have to carry one kind of wire around. No-brainer, in my books.

[cglaeser 0]

I just don't understand why this is not deemed "professional".

 

In addition to the potential voltage drop mentioned above, many alarm installers refuse to use 24AWG for power because it is so fragile. A nick while stripping or a tight terminal screw can easily break 24AWG. PoE avoids these problems because the higher voltage reduces the current and the RJ45 connectors avoid the need to strip or use terminals screws.

 

Best,

Christopher

[Soundy 1]

I just don't understand why this is not deemed "professional".

 

In addition to the potential voltage drop mentioned above, many alarm installers refuse to use 24AWG for power because it is so fragile. A nick while stripping or a tight terminal screw can easily break 24AWG. PoE avoids these problems because the higher voltage reduces the current and the RJ45 connectors avoid the need to strip or use terminals screws.

 

Best,

Christopher

 

I've actually had more breaks from nicking the wire while cutting off the jacket, than I have from stripping the individual wires. And I usually use a pair of small flush-cutters for stripping stuff that small. It's really not a big an issue as some people make it out to be.

 

In any case, use tool-less baluns and B-crimps that bite through the insulation, and you don't have to worry about stripping the inner wires at all.

[fas 0]

Soundy what do those b clips look like? I have some that have a gel like insulation in them. I always thought you had to strip the wires though.

 

Getting back to using cat5e as an all in one solution: In the control room where the dvr and power box are located, how do you separate the power wires and the video wires? I'm guessing you strip the cat5e and separate the wires and put a balun on for video and connect the power wires to the power box, but the wires are so thin, do you use anything to protect them since they no longer have a jacket on them? If the power box and dvr are not close to one another you might have a long run of cat5e wires with no jacket which could easily get knicked or ripped out. How do you handle this?

[Soundy 1]

Soundy what do those b clips look like? I have some that have a gel like insulation in them. I always thought you had to strip the wires though.

 

These ones (the gel-filled ones are blue):

 

The ones we use, at least, if you look inside, they're lined with little teeth that can bite through the wires' insulation when you crimp them down. They're small, so you do usually need to strip larger wires just so they'll fit, and you'll certainly get a more reliable connection by stripping first, but I've regularly used them without stripping as well.

 

Getting back to using cat5e as an all in one solution: In the control room where the dvr and power box are located, how do you separate the power wires and the video wires? I'm guessing you strip the cat5e and separate the wires and put a balun on for video and connect the power wires to the power box, but the wires are so thin, do you use anything to protect them since they no longer have a jacket on them? If the power box and dvr are not close to one another you might have a long run of cat5e wires with no jacket which could easily get knicked or ripped out. How do you handle this?

 

I've done it a variety of ways. You can terminate everything to a punchdown block (BIX, or whatever)... I've used the string to split the jacket, pulled out JUST the video pair, then run all the video pairs together over to the DVR, wrapped in split loom... I've also ended everything at the DVR then extended the power runs to the PSU with 18/2... really, it depends on the specific installation.

[fas 0]

Those are good solutions. I just wouldn't want to leave thin cat5e wires hanging or extending into another room all by themselves.

[Soundy 1]

Well, you can always mount the DVR and power supply closer together. In one instance, we terminated at the PSU and used four Cat5e runs to extend 14 video feeds from there to the other end of the desk, where the DVR was. Or like I say, the long runs can be protected by conduit, loom, etc. Lots of possibilities!

[fas 0]

I like the idea of terminating at the power supply and extending video feeds with cat5e. This way everything is jacketed and better protected. This sounds like the best way to go. It's neater too. I think I will use this method for the upcoming job.

[Soundy 1]

Sounds like a ground loop problem to me - it's common when using baluns with *cheap* 12VDC cameras, because they share the power and video grounds internally. It has nothing to do with proximity of the power supply to the DVR, it's because you end up with two ground paths of different lengths to each camera.

 

Any camera that has an internal power regulator (including 24VAC and dual-voltage types) should be free of the problem, even with a 12VDC supply, because the regulator isolates the power ground from the video ground.

 

The only workaround that's really effective is a separate wall-wart power adapter for *each* 12VDC camera.