r/electricians • u/bhokolatebhipbookies • 7d ago

Code question

I’m currently doing my advanced level schooling and I got a code hw question that says “…a 480-240 XFMR has 90°c rated termination, the primary side is fed with RW90XLPE (unjacketed) and the secondary is fed with tw75…”.
If terminations are rated for 90° how can you use a 75 degree insulated conductor?

EDIT: this is based off the CEC

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u/LevelUpLenny 7d ago

Because the conductor only has to meet or exceed the temperature rating required for the actual load conditions. A 90°C termination can accept a 75°C conductor, you just size and ampacity-rate the conductor using the lower 75°C rating. Happens all the time in real installs.