48V DC and data in same cable

[storeytime]

I have a customer who wants to know if CAT5 cable can be used for this scenario. Power supply is a UPS for the computer system, 48V DC.
The power and data supply 11 WAP's. (Wireless Access Points) They will be mounted in the ceiling, in corridors of a hospital. (Not in patient areas)He wants to run power and data in same cable. At first I told him he couldn't do it. Now that I check the code, I'm confused. The power looks like a class 3 circuit to me. That would require a minimum wire size of #18 if I'm not mistaken. I think CAT5 is twisted pairs of #24. Total amperage for all the WAP's is 1.21 amps. If this is not possible, can we run some kind of plenum rated cable for the power and use the CAT5 cable for data. Or is there another kind of cable that can be used to handle both needs in the same cable. I'm obviously new to this kind of work, so any help would be appreciated.

 

[LawnGuyLandSparky]

Re: 48V DC and data in same cable

It sounds like your customer is suffering from "It's low voltage so I can run it through anything" syndrome. Wire & cable suppliers will custom spool almost anything you can dream up.

 

[don_resqcapt19]

Re: 48V DC and data in same cable

I have never used it, but the IEEE standard now allows (or soon will) "Power Over IP". In the first version of this standard, the DC power is routed over the unused pairs of the CAT-5 cable. I think that you are limited to less than 15 watts, but am not sure. In the second version, the DC power in on all of the pairs along with the data. This version permits more power on the cable.
Don

I should have said "Power over Ethernet" (PoE)and not "power over IP".

[ February 14, 2006, 08:40 AM: Message edited by: don_resqcapt19 ]

 

[storeytime]

Re: 48V DC and data in same cable

Thanks everybody. I found a good article on power over ethernet at Wilkepedia. It does allow the power to be run over one of the twisted pairs on CAT5.

 

[don_resqcapt19]

Re: 48V DC and data in same cable

It appears that there are a number of vendors that have equipment to do what you want. take a look here.

 

[masterinbama]

Re: 48V DC and data in same cable

I installed a security camera system in a local fraternal club that uses the same catIV for video,audio and power for the cameras.the last pair is an alarm circuit in case someone unplugs a camera

 

[satman]

PoE

PoE

Power over Ethernet is limited power and is designed to operate Ethernet devices. I wouldn't use cat wire for anthing but a UL approved intended purpose. 22 and 24 gauge wire make a good heater and plenum burn just as good as non-plenum coverings.

satman

 

[bensonelectric]

This is a common thing with corporate acess points as the best location to mount them is on the celing, and you're never gaurenteed to have a receptical where you need it. Usually the "power injectors" come with the specific brand of WAP, on one side you have a RJ-45 out to the WAP, and on the other you have a RJ-45 that goes to the rest of your network. The "power injectors" are listed for this purpose, I think that you should only use one of them designed for your specific WAP, and not try and do a build it yourself sort of thing.

Each WAP will require it's own home run back to the router closet where the "power injectors" are located.