# Power over ethernet... ground fault?



## NJSparky (May 21, 2014)

jza said:


> I've got a call about multiple power over Ethernet supplies energizing the metallic casing with about 50vDC.
> 
> Anyone ever encounter this before?


Metallic casing? are you talking about screened twisted pair?


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## FrunkSlammer (Aug 31, 2013)




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## Service Call (Jul 9, 2011)

I do power over Ethernet but it's for Christmas lights that I do to music. I interject 12VDC over the cat 5 cable to run power for light LED loads. Don't know if this is the same thing you're talking about or not.


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## NJSparky (May 21, 2014)

Poe is typically for things like wireless access points and ethernet phones, where power is injected onto a spare pair in the cable so a device doesn't need its own 120v plug and transformer. power can be put on the cable inside the switch or "injected" through an external power injector.


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## FrunkSlammer (Aug 31, 2013)

Sounds like defective equipment.

I've done a bunch of POE, and never had any problems... not with the power anyway!! :laughing:


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## jza (Oct 31, 2009)

This is 48vDC...


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## NJSparky (May 21, 2014)

Yes, we get it, 48vdc, that's poe. what metal casing are you referring to??


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## RIVETER (Sep 26, 2009)

jza said:


> I've got a call about multiple power over Ethernet supplies energizing the metallic casing with about 50vDC.
> 
> Anyone ever encounter this before?


What is the voltage of your Ethernet?


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## jza (Oct 31, 2009)

NJSparky said:


> Yes, we get it, 48vdc, that's poe. what metal casing are you referring to??


The metal casing of the POE power intercom/phone system.



RIVETER said:


> What is the voltage of your Ethernet?


48vDC.


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## 8V71 (Dec 23, 2011)

Hmmmm....our equipment is not compatible with POE and we terminate the unused pairs through a 75 ohm resistor to ground. So it could be our junk or somebody else does the same thing. :boat:


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## FrunkSlammer (Aug 31, 2013)

Is it real power though? People are getting shocked or something?


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