will each camera add to power consumption of PoE switch?

[BrownChiLD 0]

Hi Guys

 

I have a poE switch w/ peak power consumption @ 72w..

 

It claims to be able to provide 15.4w per port

If i have cameras attached to all ports, consuming that much wattage, that's a total of 123.2W...

 

so questions:

1) How the heck does that work? When Switch only consumes max 72w from the 220w wall, how can it provide 123w output power?

2) When calculating how much total wattage my surveillance system will consume, do i have to add the camera wattages? or just the PoE Switch total wattage?

 

EG.

My system has:

8 cameras rated at 5w each (40w total)

8port poe consuming 72w max.

NVR, monitor, etc.. @ 200w.

 

Total power consumption of the system is 312w??

 

 

regards

[Boogieman 1]

Hi Guys

 

I have a poE switch w/ peak power consumption @ 72w..

 

It claims to be able to provide 15.4w per port

If i have cameras attached to all ports, consuming that much wattage, that's a total of 123.2W...

 

so questions:

1) How the heck does that work? When Switch only consumes max 72w from the 220w wall, how can it provide 123w output power?

2) When calculating how much total wattage my surveillance system will consume, do i have to add the camera wattages? or just the PoE Switch total wattage?

 

EG.

My system has:

8 cameras rated at 5w each (40w total)

8port poe consuming 72w max.

NVR, monitor, etc.. @ 200w.

 

Total power consumption of the system is 312w??

 

 

regards

check the specs...the switch can do 15.4 PER port but there is also a total max of 72 in your case...most cameras only consume 3-4w. the poe switch itself is NOT consuming 72w...that is with the MAX load attached.

[BrownChiLD 0]

Yeh that's what confused me. It promises 15.4W power to each PoE device.. so if i have 8 devices maxing out 15.4w (for example) will this PoE switch able to handle it? and how much wattage will it consume in that case? 72W peak consumption? or the actual 123.2W needed to give max power to all poe devices attached?

 

still confused/

[Boogieman 1]

Yeh that's what confused me. It promises 15.4W power to each PoE device.. so if i have 8 devices maxing out 15.4w (for example) will this PoE switch able to handle it? and how much wattage will it consume in that case? 72W peak consumption? or the actual 123.2W needed to give max power to all poe devices attached?

 

still confused/

It will not be able to support 15.4w on all ports ..it will max out at 72w...this is how these switches are rated..it is rare to need 15.4 on each port..

[BrownChiLD 0]

Yeh that's what confused me. It promises 15.4W power to each PoE device.. so if i have 8 devices maxing out 15.4w (for example) will this PoE switch able to handle it? and how much wattage will it consume in that case? 72W peak consumption? or the actual 123.2W needed to give max power to all poe devices attached?

 

still confused/

It will not be able to support 15.4w on all ports ..it will max out at 72w...this is how these switches are rated..it is rare to need 15.4 on each port..

 

Ok so when calculating for total watts consumption, i will just refer to max power of switch (72w) and no need to count the number of cameras on and each of the camera rated draw?

 

Because the combined total wattage draw of all cameras attached on a PoE switch will never exceed the maximum wattage capability of the switch, correct?

 

Regards

[Boogieman 1]

Yeh that's what confused me. It promises 15.4W power to each PoE device.. so if i have 8 devices maxing out 15.4w (for example) will this PoE switch able to handle it? and how much wattage will it consume in that case? 72W peak consumption? or the actual 123.2W needed to give max power to all poe devices attached?

 

still confused/

It will not be able to support 15.4w on all ports ..it will max out at 72w...this is how these switches are rated..it is rare to need 15.4 on each port..

 

Ok so when calculating for total watts consumption, i will just refer to max power of switch (72w) and no need to count the number of cameras on and each of the camera rated draw?

 

Because the combined total wattage draw of all cameras attached on a PoE switch will never exceed the maximum wattage capability of the switch, correct?

 

Regards

No that is not true...some cameras require 10+ watts...its depends on what cameras you are connecting...if your cameras only draw 5w then its a non issue since you will only draw 40w max.

[ssnapier 0]

Find the spec sheet for your cameras and find the POE class or total power consumption for each unit. Once you have that figure do the math. If it adds up to more than 72 watts then you need a different switch or you need to inject power to a few cameras from a midpsan.

[BrownChiLD 0]

Find the spec sheet for your cameras and find the POE class or total power consumption for each unit. Once you have that figure do the math. If it adds up to more than 72 watts then you need a different switch or you need to inject power to a few cameras from a midpsan.

 

 

ok thanks. i think this pretty much answers my main question.. the cameras can only consume combined wattage max of what the switch can take in (72w) . therefore when deciding on a UPS for the system, i will calculate consumption of DVR and Switches only, no need to add a per camera wattage on top of that.

 

tnx

[Boogieman 1]

Find the spec sheet for your cameras and find the POE class or total power consumption for each unit. Once you have that figure do the math. If it adds up to more than 72 watts then you need a different switch or you need to inject power to a few cameras from a midpsan.

 

 

ok thanks. i think this pretty much answers my main question.. the cameras can only consume combined wattage max of what the switch can take in (72w) . therefore when deciding on a UPS for the system, i will calculate consumption of DVR and Switches only, no need to add a per camera wattage on top of that.

 

tnx

If you do this you will overbuy. Suppose the switch has 7 cameras attached and each is only drawing 4 watts...add say another 5 for the switch and you are at 33...why would you use 72w to compute your needs?

[BrownChiLD 0]

Find the spec sheet for your cameras and find the POE class or total power consumption for each unit. Once you have that figure do the math. If it adds up to more than 72 watts then you need a different switch or you need to inject power to a few cameras from a midpsan.

 

 

ok thanks. i think this pretty much answers my main question.. the cameras can only consume combined wattage max of what the switch can take in (72w) . therefore when deciding on a UPS for the system, i will calculate consumption of DVR and Switches only, no need to add a per camera wattage on top of that.

 

tnx

If you do this you will overbuy. Suppose the switch has 7 cameras attached and each is only drawing 4 watts...add say another 5 for the switch and you are at 33...why would you use 72w to compute your needs?

 

Thanks for that.. but i figured it would be quicker, safer, and less hassle to calculate max load potential of each camera cluster based on max load of switch, rather than calculate or gauge exactly per camera requirements ... If i "overbuy" UPS power for, say, a 72w system, then it's ok because the excess UPS power will just go into more minutes of backup power for the system. So basically it's safer to just provide ups @ max potential load, specially if budget permits it. atleast that's my take on things.

[ssnapier 0]

In general terms it is not possible to overbuy an UPS. Obviously there are budgetary concerns, but a bigger UPS is never a bad thing!