CEC Section 8-104 Max Circuit Loading vs Table 12E (DLO ampacity) in lieu of Table 1

[tumbleweed1]

In Canadian Electrical Code- does 8-104(4)(b) [8-104(d) reads: With 100% rated circuit breaker, 85% of the rating of the circuit where the ampacity of the conductors is based on Column 2, 3, or 4 of Table 1 or 3] still apply if we're sizing DLO cable based on Table 12E [Allowable ampacities for DLO cables in a permanent installation]?

To me, Table 12E is equivalent to Table 1 with the exception that Table 12E has different sizes for the larger DLO cables (535kcmil rather than 500kcmil etc). I would figure 8-104(4)(b) would also say "circuit is 85% of the rating of conductors based on Table 1, 3, or 12E...but it doesnt.

Do we need to include an additional derate for 85% circuit rating? Code does not explicitly say 85% of ampacity based on 12E.

 

[waross]

I don't have my code handy but I seem to remember that the basis of that requirement is to prohibit running the cables at the maximum rated temperature.
I would compare the temperature rating of the DLO cable with the temperature ratings for columns 2,3,or 4.
Match the temperature rating and use that column to determine derating.

Bill
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"Why not the best?"
Jimmy Carter