PoE injector distance

[Jobos]

What is the maximum distance I can run a Ruckus 2942 AP from a PoE injector?

 

Thanks.

[plexer]

Cat5e limit is 90m so I guess that would be a starting point?

 

Ben

[jamesreedersmith]

Actually Cat 5 is certified to 110m total length

 

You are allowed a 100m structured run and a maximum of 2 5m patch leads (one each end) or a combinantion of the above.

[Jobos]

Wouldn't there will be a voltage drop over the cable run?

[Haptic]

100 Metres Fella;)

[jamesreedersmith]

Yes there may be but the 802.3AF standard allows for this and most POe injectors provide at the top level voltage but devices work at the voltage to the voltage -10% to allow for the voltage drop.

 

Thanks

 

James

[Jobos]

The caretaker tells me the distance is around 40m so the injector shouldn't have any problems with that

[jamesreedersmith]

You should be fine at that.

 

Thanks

[plexer]

Actually Cat 5 is certified to 110m total length

 

You are allowed a 100m structured run and a maximum of 2 5m patch leads (one each end) or a combinantion of the above.

 

I believe it to be 90m for the structured cable and 2 x 5m patch leades.

 

Ben

[m25man]

I just had an interesting scenario where 6 3Com AP's all connected back to the same Cisco POE switch would randomly reset themselves!

After a lot of testing and elimination we found that one of the AP was over 60 Meters and 3 patch cords downstream.

The switch was not a problem the uptime was 200 days but all 6 APs would be regularly at random be restarted. It was first thought to be the WX Controller initiating the reset of the AP's but since removing the furthest AP from the switch and giving it it's own Midspan no further problems?

 

I have also tried running Cisco Dual Band AP's on cheap Level One Midspans, anything over 20 Meters and they dropped off line, put a Cisco poe on them and they were fine at over 50 Meters.

 

I still have to carry out some certification of the troublesome link/patch cords but seeing how easy it is to damage the insulation on any CAT5 cable, one would really need to be certain that any POE drop is tested for potential issues.

 

I would never "asume" just because an old 10mb print server used that link once it was good for anything else you want to hang off the end of it!

 

Voltage drop on POE is most definately a potential problem.

 

Make sure your device and it's supply is adequately matched and that the connecting cable is up to the job.