Splitting POE from switch

[bob_4323]

i I am considering using a POE switch to power some mini IP Cameras:

http://www.ebay.co.uk/itm/CCTV-4-Port-Ethernet-10-100M-PoE-Switch-Hub-for-IP-Camera-Power-Supplier-/121535641408?pt=LH_DefaultDomain_3&hash=item1c4c16b740

I also want to power a separate microphone - situated next to each camera - can someone tell me if this will work:

One end of CAT45 plugged into POE Switch,
Other end of CAT45 fitted with POE Splitter,
the 12v DC Connector end split, feeding 1) camera 2) Mic
(obviously the CAT45 from the splitter then goes into camera)

Images of quoted splitters below.

Also, the power supply that came with the camera (12v +/- 2.0A), make the cameras run quite hot - do POE switches supply a more measured current.

 

[alastairstevenson]

No, this will not work. But should be OK if you get an active PoE splitter, conforming to 802.3af

Your pictures show passive PoE splitter cables - the PoE switch specs show that it is 802.3af compliant, also the mention of 48v power suggests this too.
Passive splitters in the cable just use unused wires in the cable as a short power lead extension, and need an equivalent passive injector at the other (switch) end.

The cameras will run as hot as the power they consume.
Provided that you supply them with 12v (assuming that's what they require) it will make no difference if the 12v power supply is rated at 2A or 20A, the cameras will draw the same power.

 

[corkangel76]

most cameras run warm anyways... its just the nature of the beast.

 

[bp2008]

The heat level can vary based on the input voltage. Energy is lost in the form of heat whenever the voltage is transformed. For example the camera's internal guts might run on 3.3 volts or something, but be powered by a 12 volt supply or optionally 48-56 volts through PoE, either way it has to be converted before the camera can use it, and this will produce heat. Of course the other operations also produce heat, but often a significant portion of it is the voltage conversion.