It addresses Mineral-Insulated, Metal-Sheathed Cable, which is Type MI [332.2].
This cable consists of copper conductors coated by inorganic magnesium oxide
powder and run inside a copper sheath (it may be a steel alloy sheath).
reason to run this cable is you need to withstand the high temperatures involved
in a fire; so, for example, you use it for your life safety systems. You can find out more
about Type MI cable at
You can use
Type MI cable in eleven different defined applications [332.10].
can't use it in underground runs, unless you ensure it's protected from physical
damage. And you can't use it where it's exposed to conditions that may destroy
or corrode the metal sheath, unless you provide additional protection to prevent
said destruction or corrosion [332.12].
answering that question, it's worth noting that the support issue is moot if you
damage the cable during installation by exceeding its bend radius [332.24].
Generally, you must support the cable every 6ft (or less) using staples, straps,
hangers, or similar fittings [332.30(A)]. But you don't have to
support this cable if it's fished between access points in concealed spaces of
finished structures, or supporting is impractical [332.30(B)].
You can use
any terminations suitable for the conductors. You must also use an end seal
fitting where the cable terminates and you must install it immediately after
stripping so moisture does not enter the insulation. You must also provide
insulating material to each individual conductor. And, you must use fittings listed and
identified for use with Type MC Cable [332.40].