Minimum clearance phase to ground 21.5kV system

[edienberg]

I have a generator cooling room that houses the neutral connection point as well as the line side connection to interface with our IPB. The conductors used are rigid Al. tubes. Can somebody point me to a CSA or CES code/table that would address the clearance required from phase to ground? Similar to NEC 490.24? Table 30 of the OESC would seem to be what I am looking for, but does not address phase to ground.


Thanks for the help,
Erik