4-004 (1) c de-rating for more than 3 conductors.
Electricians know how to calculate a voltage drop, or use table D3 to find it.
Finding a power loss is just one more calculation.
Code should have a table like D3 for power loss. and it should be used instead of 5c.
Some de-ratings for amount of conductors are overdone.
Other times we should de-rate, even if the code doesn’t call for it.
Heat loss of fully loaded free air conductors is painful for anybody paying Ontario’s electricity rates.
In some instances they have to pay for the heat losses twice if they air-condition their plant.
4-006
When it comes to de-rating a 90 degree conductor because the circuit breaker is only 75 degree rated,
the conductor has to be de-rated only at the connection to the breaker. The rest of the run is fine.
I can splice the wires in a junction box 3 feet before the breaker and run larger conductor the last 3 feet.
I would like to see the code allow running the conductor without de-rating, and find a way to cool the conductors before the breaker. like running larger conduit last couple of feet, or have a longer loop of the wire in the panel, before it’s connection.
Electricians know how to calculate a voltage drop, or use table D3 to find it.
Finding a power loss is just one more calculation.
Code should have a table like D3 for power loss. and it should be used instead of 5c.
Some de-ratings for amount of conductors are overdone.
Other times we should de-rate, even if the code doesn’t call for it.
Heat loss of fully loaded free air conductors is painful for anybody paying Ontario’s electricity rates.
In some instances they have to pay for the heat losses twice if they air-condition their plant.
4-006
When it comes to de-rating a 90 degree conductor because the circuit breaker is only 75 degree rated,
the conductor has to be de-rated only at the connection to the breaker. The rest of the run is fine.
I can splice the wires in a junction box 3 feet before the breaker and run larger conductor the last 3 feet.
I would like to see the code allow running the conductor without de-rating, and find a way to cool the conductors before the breaker. like running larger conduit last couple of feet, or have a longer loop of the wire in the panel, before it’s connection.
