Nothing in the regulations contained in this Chapter shall prohibit the
installation of other types of permanently placed electrical heat‑generating and
emission units not presently covered herein when such units are approved by the
Underwriters’ Laboratories, Inc., and installed in a manner approved by such
Laboratories providing they meet the general provisions of this Chapter and
further that a separate disconnect shall be provided in each heated space,
except that no individual thermostatic control shall switch any combination of
heaters totaling more than 7 kilowatts.