Power supply for CNB 24VF cameras

[btrotter 0]

I have installed a number of CCTV cameras in the past, but they were the ones which required a plug. The cable I would run from the PC to the camera would have the BNC connector and the 12v plug in the same cable.

 

Looking at the CNB cameras, it looks like it has different power requirements. First it can be either 24 or 12v. From what I have been able to figure out, it looks like you would use 24v if the run was going to be a considerable distance from the power supply, otherwise 12v would be perfectly suitable. Can someone confirm or comment if that is the only advantage of 24v over 12v.

 

The next thing is, what physical hardware is now required to be able to run power?

I saw that if 24v was used, I could run cat5 cabling and use two of the pairs of cable to run power. It didnt list this as an option for 12v though.

So what type of cable is required to run 12v? Can it still run on cat5 cabling, or are the amps too high?

 

I assume you would run all this back to a wall-mounted multi-power supply which can provide around 500ma per channel? Looking at the CNB power consumption, it is listed as 300ma, so the amperage should be enough. It is mainly the physical cabling I am wondering about.

 

Thank you.

[Bean00 0]

The Basics:

24VAC works better for long distances and the powersupplies tend to be cheaper(though the cameras usually cost more - which more than offsets this.).

 

Technically, you can run 12VDC over cat5, but only for VERY short runs. The issue isn't amperage(though that is a factor in the overall issue), it's voltage drop. Amperage effects voltage drop, which is why it is a factor.

 

You usually have an approx 10% tolerance in electronics to work with. That means using 12VDC you need to remain within 10.8v-13.2v. 24VAC however, that same 10% gives you 21.6-26.4v range. That gives you a substantially larger drop in voltage to work with.

 

CAT5, being a very small gauge cable(24awg), has a very large voltage drop. Match your cable to your distance. 18-2 is good most of the time, but sometimes you need a larger gauge cable for really long runs.

 

Useful - Voltage Calculator

[Bean00 0]

Oh and premade cables are usually junk. I'm suprised you haven't had issues in the past related to cabling.

[btrotter 0]

With that in mind, it sounds as though I am better off just going with 24V, especially since the CNB cameras handle 24v and 12v.

[Bean00 0]

yep... though if you plan to use CAT5, remember to use the voltage calc.

 

And I'd use 0.5 amp at current, not 0.3 amps for the calc. Always good to be on the safe side. that 10% is a guideline, not a firm rule. Especially since equipment can spike over what the MFG says it uses.

[btrotter 0]

yep... though if you plan to use CAT5, remember to use the voltage calc.

 

And I'd use 0.5 amp at current, not 0.3 amps for the calc. Always good to be on the safe side. that 10% is a guideline, not a firm rule. Especially since equipment can spike over what the MFG says it uses.

 

What do you mean about using the "voltage calc"?

 

By the way, thank you for your help.

[Bean00 0]

Voltage Calculater

 

 

I put that link in my first post.

[Soundy 1]

Technically, you can run 12VDC over cat5, but only for VERY short runs. The issue isn't amperage(though that is a factor in the overall issue), it's voltage drop. Amperage effects voltage drop, which is why it is a factor.

 

...

 

CAT5, being a very small gauge cable(24awg), has a very large voltage drop. Match your cable to your distance. 18-2 is good most of the time, but sometimes you need a larger gauge cable for really long runs.

This is why you double- or triple-up the wires in the Cat5. I normally use the blue pair for video, the orange and green pairs for power (orange and orange/white for 'AC hot' or 'DC+', green and green/white for 'AC neutral' or 'DC-' or ground), and leave brown as a spare. Two 24awg wires together give you the equivalent of about 21awg; three are equivalent to 18awg.

 

Useful - Voltage Calculator

 

This one's even better for calculating for Cat5: http://www.netkrom.com/voltage_loss_over_cat5_calculator.html

[btrotter 0]

Got it. Thanks guys!

[Bean00 0]

I like that calculator... though whats with the 300ft ethernet restriction lol. Only reason you would use this for a POE calcs is if your not using standards based equipment.

[Soundy 1]

I have installed a number of CCTV cameras in the past, but they were the ones which required a plug. The cable I would run from the PC to the camera would have the BNC connector and the 12v plug in the same cable.

 

Looking at the CNB cameras, it looks like it has different power requirements.

Welcome to the world of professional equipment!

 

First it can be either 24 or 12v. From what I have been able to figure out, it looks like you would use 24v if the run was going to be a considerable distance from the power supply, otherwise 12v would be perfectly suitable. Can someone confirm or comment if that is the only advantage of 24v over 12v.

24VAC supplies tend to be cheaper, as Bean notes, because they require no more than a transformer to step down the line voltage. 12VDC supplies either add a rectifier and filter to the step-down transformer (to convert the transformer's AC output to DC), and sometimes a regulator, or use a PWM module to step the line voltage down and output DC.

 

24V does suffer less loss over long distances, however with sufficiently sized wire, this won't be an issue in probably 99% of DIY installs.

 

There are still a few cameras around (mostly higher-grade ones) that will operate on 24VAC only, but most newer ones accept dual-voltage input, like the CNBs.

 

The next thing is, what physical hardware is now required to be able to run power?

I saw that if 24v was used, I could run cat5 cabling and use two of the pairs of cable to run power. It didnt list this as an option for 12v though.

So what type of cable is required to run 12v? Can it still run on cat5 cabling, or are the amps too high?

Cat5 will work fine for 12V in most circumstances - see my reply to Bean00.

[Soundy 1]

I like that calculator... though whats with the 300ft ethernet restriction lol. Only reason you would use this for a POE calcs is if your not using standards based equipment.

Yeah, I dunno why they have that limitation... kinda silly.

[rory 0]

I have installed a number of CCTV cameras in the past, but they were the ones which required a plug. The cable I would run from the PC to the camera would have the BNC connector and the 12v plug in the same cable.

 

Looking at the CNB cameras, it looks like it has different power requirements. First it can be either 24 or 12v. From what I have been able to figure out, it looks like you would use 24v if the run was going to be a considerable distance from the power supply, otherwise 12v would be perfectly suitable. Can someone confirm or comment if that is the only advantage of 24v over 12v.

 

The next thing is, what physical hardware is now required to be able to run power?

I saw that if 24v was used, I could run cat5 cabling and use two of the pairs of cable to run power. It didnt list this as an option for 12v though.

So what type of cable is required to run 12v? Can it still run on cat5 cabling, or are the amps too high?

 

I assume you would run all this back to a wall-mounted multi-power supply which can provide around 500ma per channel? Looking at the CNB power consumption, it is listed as 300ma, so the amperage should be enough. It is mainly the physical cabling I am wondering about.

 

Thank you.

 

Its no different than any other camera, treat it the same. That connector just gives you something to screw the red and black from the Siamese cable into. You can use any power supply once it supplies the correct voltage and enough amps. I use a 500ma 12VDC cheap power plug to test them here, or a 1.2ma 12VDC whichever one I can reach easier without walking over too far .. at the customer locations Ive used 12VDC or 24VAC .. single power supplies and distributed boxes, depended on the install. With this camera polarity does not matter so you can put the 12VDC + and - either way into the green connector, and 24VAC can go either way anyhow. Power consumption is 180ma for the VBM-24VF. Get some RG59 Siamese cable and be done with it. If you want you could splice and use the ready made cable you have but the distance with that would be more limited, also there are other issues with that type of cable - stay clear of it if you can. If the run is over 150'-200' then best to go 24VAC.

 

If there are more 12VDC cameras on the install than the 24VFs, and all cameras are within say 50-100', eg. mounted on the eaves of a normal size building, then you could go 12VDC for all and use one box, otherwise I would go 24VAC with the 24VFs and just put the 12VDC cameras on their own supply. Really depends on the install.

[btrotter 0]

You guys are a great help. I do not do this for a living, so learning from pro's is a plus.

I have a 6 camera CCTV system on my house running through a PC based Zoneminder system which is where i learned what I do know about it. It is a low-tech system but is very customized and pretty slick. I can monitor the cameras through my mobile devices and have it set up to record both onsite and immediately upload events offsite in the event a burglar steals my DVR.

My neighbor knows about my CCTV system and asked me if i could build something for his business, which is why i am reading up on some of the more professional grade components.