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jduzan's avatar
jduzan
Follower
May 18, 2026

Some GS308EP switches do not comply with IEEE 802.3 Ethernet specifications

IEEE 802.3 Ethernet specifications require that the switches provide galvanic isolation between all ports and chassis ground.

 

this means that the POE supply is meant to be "floating" not connected to earth ground.

 

I have found several of these switches in my installations that do not comply with this standard.  I have also found those of the same model which do comply.  It seems that the newer ones do not comply.  Is there some rhyme or reason for this selective non-compliance? Can I select switches which do comply by the serial numbers? surely this is not a configuration, but correct me if I am wrong.

 

Does Netgear offer any switches which do comply with IEEE poe requirements?

 

test setup:

plug switch into POE powered device, use a multimeter to check the volts to ground of the powered to device to the earth ground of the building. If you find that earth ground is mV from the powered device ground in voltage, this switch is compliant. if you find that ground is -54V from the ground on the powered device, then the PSE is non-compliant because it is providing a voltage source REFERENCED TO EARTH GROUND. 

 

Don't believe me about galvanic isolation being a requirment?

ref: https://www.analog.com/en/resources/technical-articles/jumpstarting-ieee-802-3bts-poe.html

Hardware

6 Replies

  • FURRYe38's avatar
    FURRYe38
    Guru - Experienced User
    May 18, 2026

    Possible differences in HW or FW versions. You'd need to check FW versions to see this may make a difference. 

    Possible configuration could be a factor.

    Something to contact NG support about and see.

    JulienR​  BrettD​ 

    • schumaku's avatar
      schumaku
      Guru - Experienced User
      May 19, 2026
      FURRYe38 wrote:

      Possible differences in HW or FW versions. You'd need to check FW versions to see this may make a difference. 

       

      Extreme unlikely...

      • StephenB's avatar
        StephenB
        Guru - Experienced User
        May 19, 2026
        schumaku wrote:

        Extreme unlikely...

        Certainly not FW.  Obviously is hardware/circuitry, but maybe not linked to a specific HW revision.

  • schumaku's avatar
    schumaku
    Guru - Experienced User
    May 18, 2026

    Have thought about the problem might be caused on the PD end?

     

    Does the issue move along with moving the PD to another port?

     

    What make and models of PD are we facing here? 

  • BrettD's avatar
    BrettD
    NETGEAR Employee
    May 19, 2026

    The article you reference, relates to POE++ (802.3bt) however the switch you are testing is not a 802.3bt switch - it is only POE+ 802.3at. Can you confirm another Netgear switch you tested that provides a different result from your test?

    • schumaku's avatar
      schumaku
      Guru - Experienced User
      May 19, 2026
      BrettD wrote:

      The article you reference, relates to POE++ (802.3bt) however the switch you are testing is not a 802.3bt switch - it is only POE+ 802.3at

       

      Block schematic does essentially not differ between ++ and +

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