Metal Trunking screed into floor

[derek_bartram]

I'm trying to determine which Reference Method from BS7671 applies for: earthed metal trunking 50mm/50mm chased into a solid screed floor (screed in, then floorboards/carpet/laminate on top)

Best guess:
#45-46 cables in ducting in masonry with thermal resistivity not greater than 2K.m/W
Is ducting the same as trunking?

#59-60 cables in conduit in masonry
Conduit isn't trunking (you can't open it), but is trunking conduit (if you don't open it)

In both cases the result is use Reference Method B, so do I just ignore the fact I don't strictly know?

Possible but unlikely:
#40-42 void/conduit
#43-44 void
#50-51 flush to floor
#118-120 close, but massive dimensions

Discounted:
#1-9 wall
#10-11 are suspended
#12 mouldings
#13-14 deleted
#15 architrave
#16 window frames
#17-19 doesn't exist
#20 wall
#21-22 ceiling
#23 not used
#24-29 don't exist
#30-32 trays
#33-34 wall
#35 suspended
#47 void / suspended floor
#36 insulators
#37-39 doesn't exist
#52-53 implies wall, vs 50-51
#54 conduit
#55-56 ventilated
#57-58 direct in masonry
#70 armoured
#71 deleted
#72-73 direct in ground
#74-99 doesn't exist
#100-101 ceiling
#102-103 wall
#104-116 doesn't exist
#117 ventilated