Power Over Ethernet (POE)

[KJC58]

hi

Do POE devices need to be earthed or bounded 

We are installing some Cisco APs externally and Cisco install doc talk about bounding but as these are ELV devices do they need an earth

speaking with other guys the general feeling is that earthing them could actually create a earth problems 

cheers 

 

[binky]

they only work at 12v or 24v as far as I recall, they aren't putting 240V down cat5 

 

[Badger]

they may mean they neeed binding within the routers menu setup to stop the ip address being changed upon reboot each time.

 

[Sharpend]

Some types of CAT cables do have a shielding that is earthed but this is usually for more sensitive installations. 

 

[Andy™]

they only work at 12v or 24v as far as I recall, they aren't putting 240V down cat5 

48 volt. 2 pair for data, 2 pair for power, although some can run data & power down the same pairs

 

[kerching]

Some types of CAT cables do have a shielding that is earthed but this is usually for more sensitive installations. 

Earthing this at both ends can also result in a whole world of pain

 

[Sharpend]

Earthing this at both ends can also result in a whole world of pain

Oh boy can it! 

 

[Andy™]

Earthing this at both ends can also result in a whole world of pain

got to be a story to go with that. something alone the lines of you advised them not to do it that way but they knew better than you and done it anyway. then you got to laugh at them when they asked you to fix it after it went wrong

 

[Sharpend]

got to be a story to go with that. something alone the lines of you advised them not to do it that way but they knew better than you and done it anyway. then you got to laugh at them when they asked you to fix it after it went wrong

i was thinking along the lines of ‘Andy will be a long shortly as him and Kerching share so many similar experiences electrically’ no I’m thinking maybe you should join forces to write a book ‘the trials and tribulations of a humble Spark’ 

:C  

 

[kerching]

got to be a story to go with that. something alone the lines of you advised them not to do it that way but they knew better than you and done it anyway. then you got to laugh at them when they asked you to fix it after it went wrong

Got it in one. They said I was too expensive so they got the local spark to "copy what I had done previously ". What a Up

data would have been less corrupt if they had put it in a bucket and carried it. And they had left a load of "stripped and untwisted slack" in the back box

not as good as the one where they had done some serial printer links in 4 pair ( cable of 'colour' paired with red, green, blue and yellow. Didn't use the "cores of colour". When they installed a piped music system with 100v loudspeakers the signal,was induced into the  unused "cores of colour " and at break time when music switched off it pulsed the lines and all printers printed total For 2 minutes!!

 

[KJC58]

hi Guys 

we do a lot of data and I think we have all lived through horrors of the grounding of shielded cables, one end or both or just not at all. That's not the issue.

I'm just after the regs on earthing these boxes (APs) 

As they are being supplied (-58VDC) directly from the Cisco Network switch over Cat6 UTP cables do they need to be earthed 

This is below the 120VDC which means its in ELV range 

Will I be causing a possible Earth potential issue by earthing/grounding the box 

 

[binky]

I've never known such devices to need earthing , but then I don't fit much of this gear. Cat 6 as per any cat cable utilises twisted pairs to neutralise any induced voltages from wireless signals such as TV and radio without shielding, so I would ask yourself what would earthing the APs achieve, if anything? Last pair of such aerials I fitted were all plastic body with no way of bonding anything, they just had a RJ45 connection. 

As far as I am aware there are no regs for such data gear,  you are working with milli-amps.  However if manufacturers instructions says they need bonding, then bond, although I suspect it may be a case of they only need bonding under certain conditions, or in certain countries? Most manuals are written for multiple countires, so aren't alwats clear. Perhaps contacting CISCO tech help may the way forward, or, you could just install and see if they work 

 

[rapparee]

hi

Do POE devices need to be earthed or bounded 

We are installing some Cisco APs externally and Cisco install doc talk about bounding but as these are ELV devices do they need an earth

speaking with other guys the general feeling is that earthing them could actually create a earth problems 

cheers 

I never did. 

I hung mine with threaded bar off cable tray, never had any problems 

 

[Sidney]

Cisco do like their equipment tied back to the MET. Many manufacturers use the equipment chassis as the 0 volt reference and also the bond stop the build up of static electricity which can corrupt data.

 

[KJC58]

Thanks for your reply's