reliability PoE Switch vs Injector reliability

[GeorgeB123]

Hey all, I'm LF information about PoE switches vs poe injectors failure rates and whether or not 2 poe injectors would be a better pick for 2 IP cameras over 1 poe switch (unmanaged) for an extended period of time in a closed environment.

Couldn't really find useful info by googling it. 

IMO Injectors would be more reliable because they are simpler and pretty much just a power source, whereas switches have L2 networking which makes them a bit more complex with more things to break.

However, 2 injectors might be less reliable than 1 switch, since there's everything times 2 and therefore higher change of sth giving out.

 

Thanks in advance!

[mariushm]

Your reasoning is kinda bad. 

 

Switches are these days a very well understood technology, they basically make network switches on a chip more or less... there's not much that could go bad when it comes to moving data packets between ports. 

 

Power injectors are simple, just a power supply, but most of the time they're designed to be compact and sealed (so that water / humidity won't get in). Therefore, the "power supply" inside the injector will most likely operate at much higher temperatures and could potentially have some of its components degrade over time due to heat... and eventually go bad.  Picture laptop adapter power supplies, external power brick for monitors... they can go bad due to heat. 

 

The power supply in a switch may be operating at lower temperatures, there's usually ventilation holes in switches and networking equipment (unless it's on purpose designed for external use) and there may even be fans pushing air through the switch case. Even if there's no fan, there's natural air movement that most likely would provide better ventilation. 

 

In addition, the power supply would most likely be oversized for the job, so it won't run as close to the maximum and won't be as hot. For example, your 18w power injector would most likely be designed with a chip and components rated for maximum 25-30 watts, to save costs ... but a  5-8 port switch which advertises 15w per port or something like that, would have at least a 65w power supply ... so your two cameras would not even get close to 50% of the switch power supply's capabilities.

 

So what I'm basically saying is that the power supply inside a switch may have a much higher reliability/endurance/mtbf "score" compared to standalone power injectors.