Cable tray bonding requirements 5kv Teck Cable

[Kingstonrupp]

Hello,

I am intending on using aluminum cable tray for a 5kV system as my bonding conductor, which is allowed per Canadian Electrical Code. Reading through section 36, I do not see anywhere that dictates otherwise (at least not clearly). All cables are teck with separate bonding conductors. And the system is high resistance grounded.

Thoughts and input?

Thanks

 

[Kiribanda]

Your 5kV TECK cables should have their own bonding conductors plus the shields connected to the same ground
points at both ends. So your ground fault return path is your bondig conductors of each cable.
Tray is a supplement to the bonding conductor.

 

[Kingstonrupp]

Thanks Kiribanda. The 5kV cables are not shielded.

I should clarify. My question is more to do with the cable tray itself. Canadian Electrical Code allows for cable tray to be un-bonded to ground as long as all cables are armoured and there is signage. I don’t feel comfortable with this at 5kV. So I am proposing to simply bond the tray to structural steel (piles). No dedicated bonding conductor would be run in the tray though. I know this is OK for LV per section 12, but is this still acceptable at high/medium voltage?

Thanks

 

[waross]

The last time that I checked(not sarcasm, I haven't looked at that section for a few years) Equipment mounted on grounded structural steel was deemed to be bonded.
That notwithstanding, the petro-chemical industry has requirements in excess of the CEC.
A grounding conductor is installed in the tray along with the cables.
As I remember, the grounding conductor is clamped to the tray with an approved cable clamp every 50 feet and at expansion joints.
Aluminum, copper and rain are a bad mix.
Rain water is acidic enough that it will react with copper and produce salts that are corrosive to aluminum.
This is addressed by painting each clamp and an inch or so perimeter of the surrounding aluminum with Glyptol paint.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Kiribanda]

I think what you suggest is correct. As long as the cables are TECK with bonding conductors
you donot want to run a dedicated bonding conductor for the tray. But as you have suggested
since the tray is an extraneous conductive part, you have to bond the tray to the structural
steel. But finally the structural steel (also extraneous conductive parts) should de properly bonded
to the plant grounding system.