The CEC uses very similar installation diagrams and ampacity tables for determining UG ampacities as the NEC ( 0-5000V). The installation diagrams show the direct buried cables or raceways installed at 915mm (3') in various sets per phase. A recent Code seminar I attended stated the installations had to comply with the diagrams. The cable could not be installed at 750mm (30") without professional supervision as you say.
Does this sound correct? I always thought that generally the ampacity decreased as the depth increased. Shouldn't I be able to use the ampacity Tables at any depth down to that shown in the diagrams and then need engineering when that depth is exceeded.
Does this sound correct? I always thought that generally the ampacity decreased as the depth increased. Shouldn't I be able to use the ampacity Tables at any depth down to that shown in the diagrams and then need engineering when that depth is exceeded.