I did find "some" guidance here, but it still does not seem clear to me.
2-122 Use of thermal insulation
(1) Where the hollow spaces between studding, joists, or rafters of buildings are to be filled with thermal insulation, the following restrictions, as applicable, shall apply to the installation of electrical wiring in such spaces:
(a) special care shall be taken to ensure that conductor insulation temperatures are not exceeded due either to mutual heating of adjacent conductors or cables or to reduced heat dissipation through the thermal insulation;
( b) if the space is to be filled with a loose or free-flowing material that is non-corrosive, fire-resisting, and non-conductive and that is in compliance with the National Building Code of Canada, any type of wiring system recognized by this Code shall be permitted to be used, but special care shall be taken to ensure that there will be no strain on the conductors due to the weight or pressure of the insulating material;
(c) if the thermal insulation material, in the form of batts or rigid sheets, is installed prior to the installation of the wiring and secured in place so that there will be no undue pressure on the conductors, no special precaution need be observed;
(d) if thermal insulation made of or faced with metal is installed, the wiring shall conform to the following:
(i) a 25 mm separation shall be provided between the thermal insulation and the knob-and-tube wiring; and
(ii) non-metallic-sheathed cable may be in contact with the insulation; and
Δ (e) mineral-insulated cable, aluminum-sheathed cable, or copper-sheathed cable shall not be used with types of thermal insulation that are liable to have a corrosive action on the sheath.
It appears that 2-122 (1)(a) might apply here. Unfortunately the requirement to derate the cables is still a complete mystery to me. Unless I'm a complete idiot at looking at the Canadian Electrical Code, the term "special care" comes up quite often, but I have never seen a definition of that.
I'm going cross-eyed at reading the Canadian Electrical Code over and over again.
Maybe common sense would take care of those words "special care" but lately "common sense" is not an acceptable way of thinking according to most lawyers.
Anyone have any further thoughts here?
