Feeder heat loads

[wyboy]

Nec 220.50 says feeder heating loads shall be calculated at 100% of connected load. NEC 424.3 says fixed ele. Space heating shall be considered continuous duty. Does a heat load in a feeder need to be figured at 125%?

 

[raider1]

The feeder load need not be calculated with 125% of the fixed electric heating load, just 100%. (See 220.51)

The branch circuit for the fixed electric space heating equipment should be sized using 125% of the heating load. (See 424.3(B))

Chris

 

[whe4]

The blue text explanation in the NEC Handbook also include verbage that says that "the revision to consider fixed electric space heating equipment as a continuous load also impacts feeders and services that supply electric space heating equipment". This tells me that you have to calculate these loads as continuous and that a service and/or feeder needs to reflect this in addition to the branch circuit.

 

[suemarkp]

Hmmm. Then makes me wonder why 220.51 says: "However, in no case shall a feeder or service load current rating be less than the rating of the largest branch circuit supplied.". How could that ever happen if both the branch circuits and feeder were required to use the 125% factor?