Does PoE power budget matter?

[To the ocean]

hey guys,
would you think that the power budget of the PoE switches matters a lot?
I mean, for example, between 60w and 63w
I know of course that it's bigger and better, but just different a little bit, do you think it matters?

 

[ColinTaylor]

Try Google search.

DITEK Blog - Surge Protection Topics

The DITEK Blog includes current information, opinions and suggestions for a wide variety of surge protection topics.

www.diteksurgeprotection.com

 

[degrub]

you can always use injectors if you need more POE ports. What you have may be good for 1-4 devices depending on the ethernet cable losses and the device demand current. Look at the max demand spec for the device.

 

[ddaenen1]

Future-wise, POE budget will matter more and more, methinks. I power 4 AP's and two 5-port switches directly off the main Cisco switch. 2 big advantages: 1. no sockets needed, 2. all devices are on the UPS through the switch. That is a bunch of less cabling and more protection from power outages, notches or power surges. I want to add a couple of camera's, no sweat...

I can envision that also other devices such as STB's or even some small low-power servers with NVme or SSD's could be powered by POE++ in the future. There are already some routers (The ER-X had it) that can be powered by POE+.

 

[drinkingbird]

hey guys,
would you think that the power budget of the PoE switches matters a lot?
I mean, for example, between 60w and 63w
I know of course that it's bigger and better, but just different a little bit, do you think it matters?

I don't think anyone has put it quite bluntly enough.

Yes of course it matters. You not only need to watch each port (POE 15.4W, POE+ 30W, POE++ Type 3 60W, and POE++ Type 4 100W) but also the total across the entire switch.

Exceeding either one will cause you major issues.

Is 63w worth paying more than 60w, no probably not. But if you have 60W worth of devices, then that extra 3W of headroom may be what saves you from problems, however I would not cut it that close anyway.

Now of course devices don't always draw the max power all the time so maybe you'd get away with 70W of devices connected to 60W or 63W but I would never take that chance, who knows when they do a firmware update and all reboot at the same time taking a bunch of power, not getting it, and getting corrupted or damaged.

Note the port rating is going to be higher than the device rating. For example standard POE device should not draw more than about 13 watts from a 15.4 watt rated port, that is to account for the cable length and losses. However you need to account for the 15.4 watts when looking at the total drawn from the switch. So a 63 watt switch can do 4x POE 15.4 watt devices, and if it supports POE+, it can do two of those devices (or one POE+ and two POE, etc). That's why switches are usually 31 or 62/63 watt, to account for the fact that regular POE is 15.4. Could you get away with 4x POE 15.4 devices on the 60 watt - probably. Again, not something I'd really want to risk. Or if you look in the detailed specs of the 60 watt, it may actually be 62 or 63 and they're just using 60 as a nice round number on the feature list.

Long story short make sure each port is rated for the device connected to it, and you have plenty of total wattage to cover all of your devices.

 

[To the ocean]

I don't think anyone has put it quite bluntly enough.

Yes of course it matters. You not only need to watch each port (POE 15.4W, POE+ 30W, POE++ Type 3 60W, and POE++ Type 4 100W) but also the total across the entire switch.

Exceeding either one will cause you major issues.

Is 63w worth paying more than 60w, no probably not. But if you have 60W worth of devices, then that extra 3W of headroom may be what saves you from problems, however I would not cut it that close anyway.

Now of course devices don't always draw the max power all the time so maybe you'd get away with 70W of devices connected to 60W or 63W but I would never take that chance, who knows when they do a firmware update and all reboot at the same time taking a bunch of power, not getting it, and getting corrupted or damaged.

Note the port rating is going to be higher than the device rating. For example standard POE device should not draw more than about 13 watts from a 15.4 watt rated port, that is to account for the cable length and losses. However you need to account for the 15.4 watts when looking at the total drawn from the switch. So a 63 watt switch can do 4x POE 15.4 watt devices, and if it supports POE+, it can do two of those devices (or one POE+ and two POE, etc). That's why switches are usually 31 or 62/63 watt, to account for the fact that regular POE is 15.4. Could you get away with 4x POE 15.4 devices on the 60 watt - probably. Again, not something I'd really want to risk. Or if you look in the detailed specs of the 60 watt, it may actually be 62 or 63 and they're just using 60 as a nice round number on the feature list.

Long story short make sure each port is rated for the device connected to it, and you have plenty of total wattage to cover all of your devices.

Thanks for your detailed explanation, it's really helpful for me

 

[To the ocean]

Try Google search.

DITEK Blog - Surge Protection Topics

The DITEK Blog includes current information, opinions and suggestions for a wide variety of surge protection topics.

www.diteksurgeprotection.com

thanks for the recommended article