Physical damage

[Kevin007]

Hi All,
Somewhat interesting wiring method here.
I'm working on a ranch style house here in Denver. The roof is constructed of approx. 4"x 8" rafters on about 4' centers, across the top of those is 1.5" t&g, on top of that Will be 2 layers of 2" rigid foam supposedly stapled down and then a layer of rubber membrane glued to the foam.
I would like to use 4"x 2-1/8 boxes cut into the t&g to house Led inserts. What is everyone's thought on running mc. cable up there? I agree Emt. may be a better option as far as physical damage but then I get into a problem with bending a 90 down into a wall with out making a shepherds hook.

 

[ActionDave]

Are you going to router out a groove in the t&g or is the foam gonna ride over the wiring?

 

[mopowr steve]

What comes to mind is should an installation such as this be treated in the same manner as no electrical located within 1 1/2" below the deck (or as in this case the t&g) like a commercial install?
Although I'm not sure what length of fasteners would be utilized for this particular install. Would they be running screws all the way thru the t&g and into the rafters when fastening down the foam panels......I guess nail guards would be in order where mc would be crossing over the truss areas where screws could be driven?