Feeder size for heating load

[Matt Mckenzie]

When sizing a feeder for a large electric heating load do we size the feeder at a 125% or is that only for a branch circuit heating load? The book says to calculate electrical heating loads at 100% for connected service load and 125% for branch circuit sizing......? Can anybody help me clarify this?

 

[david luchini]

When sizing a feeder for a large electric heating load do we size the feeder at a 125% or is that only for a branch circuit heating load? The book says to calculate electrical heating loads at 100% for connected service load and 125% for branch circuit sizing......? Can anybody help me clarify this?

The book is correct. See 424.3(B) and 220.51.