Communications Cabinet Grounding and Bonding

[aelec84]

Hello,

Can someone please guide on the requirements for bonding and grounding communication cabinets (housing UPS/switches etc.) located outdoors? There will be power connections inside it and maybe panelboard inside it as well. Thanks.

 

[suemarkp]

If it is metal and likely to be energized, then it needs to be bonded. I would consider a cabinet with receptacles, cords, and electrical likely to become energized by some accident, failure, or fault. Bonding conductor needs to be sized per the largest circuit that could energize it.

 

[tortuga]

Here you go:

https://www.centurylink.com/techpub/77321/77321.pdf

 

[herding_cats]

Mark is correct. Find a way to bond anything metallic.

 

[ActionDave]

I would think it would be bonded already by the circuit bringing power to the equipment.

 

[ModbusMan]

I would think it would be bonded already by the circuit bringing power to the equipment.

It probably is, but telecoms like to go apesheet with bonding everything in sight. I don't even want to think about how many ground loops are created because of telecoms bonding individual comm frames to racks, power supplies and dc rectifiers to racks, racks to racks, racks to grids.... it's just a nightmare. Good luck ever finding where that stray ground current at your distribution panel is really coming from.

 

[aelec84]

Would there be a TGB (Telecom Ground bar) and a MGB (Main Ground Bar) inside where they would be bonded and a GEC from the MGB ran to GES?

 

[ActionDave]

Those are installed at the discretion of the designer.

 

[Dsg319]

I’d want at least 5 Ufergrounds ,14 grounding triads, a perimeter loop buried 7ft. All bonded together with 750kcmil coppertinned and exothermic welds holding it all together.

 

[herding_cats]

I’d want at least 5 Ufergrounds ,14 grounding triads, a perimeter loop buried 7ft. All bonded together with 750kcmil coppertinned and exothermic welds holding it all together.

I would go 1000 kcmil just to be safe. cad welds should be bonded with 24 carat gold also.

 

[ModbusMan]

I’d want at least 5 Ufergrounds ,14 grounding triads, a perimeter loop buried 7ft. All bonded together with 750kcmil coppertinned and exothermic welds holding it all together.

And that *STILL* wouldn't be good enough for the tech-school drop-out plugging in a SM fiber cross-connect.