What wattage limits are there for poured concrete indoor floors?


What wattage limits are in place according to the National Electric Code for in-concrete slab heating?

NEC 424.98 (A) Installation in Concrete or Poured masonry:  Shall not exceed 33 watts/ft2, with NO FLOOR COVERING.  Our slab rolls provide 20 watts/ft2.

NEC 424.99 (B) Installation under floor covering:  Shall not exceed 15 watts/ft2.  

Maximum cable wattage PER LINEAR FOOT:  NEC 424.44 (A) Constant wattage cables cannot exceed 16.5 watts per LINEAR FOOT.

Written by Scott Rosenbaum
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