Earthing requirements on network cable/conduit?

[Seb101]

I am helping out the village hall in our village, the committee want to extend the network in their main building to another building about 20 yards away, another local chap has offered 50m of network cable he has lying around, they want to do this as cheaply as possible (well actually they don't really want to do it, but the users of the other building are desperate for it). The buildings share a boundary and there is a fence running along the boundary so the most logical solution seems to be to run some network cable out of the wall of one building, along the fence in some conduit and into the other building.

Is this going to create any electrical grounding requirements? The cable is Cat5E and will only be carrying data (no PoE) but obviously at each end it's going to be plugged into a piece of network equipment which will be on two different electrical supplies.

If we use metal conduit for durability between the two buildings, will this create any grounding requirements? Is any of this work notifiable?

Thank you!

 

[SUNRAY]

The simple answer is maybe, depending on where the ends of the tube terminate. The use of plastic conduit will remove any doubts.

 

[bernardgreen]

The use of plastic conduit will remove any doubts

If the supplies to the buildings are from different Network cables and are TN-C-S ( PME ) then a metal connection linking the Earths will be carrying a current due to any difference in the potentials of the Neutrals ( relative to true Ground ). If a Network Neutral fault occurs then the current in the link can be high enough to damage the link cable.

The use of galvanic isolation in the data link should be considered to protect the transceiver circuits from voltage transients in the electrical supply network.

 

[plugwash]

The ethernet specs call for galvanic isolation to 1.5KV. So "normal" faults in the electricity network shouldn't affect it. Lightning can be another matter though as that can create huge potential differences.

For this reason, many installers strongly prefer to use fiber for inter-building links, particularly if their electricity supplies come from different sources.

 

[Why Not Indeed]

Ethernet is galvanically isolated.
If you really want to be paranoid, use fibre.

 

[Murdochcat]

Along a fence. Not ideal

 

[Seb101]

Along a fence. Not ideal

No but neither is digging up the carpark.