joists facing the attic or roof space.
394.30 Securing and Supporting.
(A) Supporting. Conductors shall be rigidly supported on noncombustible, nonabsorbent insulating materials and shall not contact any other objects. Supports shall be installed as follows:
(1) Within 150 mm (6 in.) of each side of each tap or splice, and
(2) At intervals not exceeding 1.4 m (4'/2 ft).
Where it is impracticable to provide supports, conductors shall be permitted to be fished through hollow spaces in dry locations, provided each conductor is individually enclosed in flexible nonmetallic tubing that is in continuous lengths between supports, between boxes, or between a support and a box.
(B) Securing. Where solid knobs are used, conductors shall be securely tied thereto by tie wires having insulation
equivalent to that of the conductor.
394.42 Devices. Switches shall comply with 404.4 and
404.10(B).