In the prelude to the questions, we gave away the fact this is a nonmetallic
conduit. We also gave away "it's a conduit" in this question. What we didn't give away is the particular type. This is
Liquidtight Flexible Nonmetallic Conduit (Type LFNC) [356.1, 356.2].
LFNC is a
nonmetallic conduit of circular cross section. It can be one of the three types
enumerated in 356.2.
356 lists seven permitted uses [356.10]. Basically, you're going to use it where
you would otherwise use a flexible metallic raceway but corrosion is a limiting factor.
That's why, for example, you might use it for a motor that's sitting under a
paper machine or in a pulping operation. It is suitable for
direct burial, if it's listed and marked for that purpose.
356 lists four prohibited uses [356.12].
One of those is in hazardous locations;
that's because plastic and static electricity tend to be ready playmates.
A second is for the protection of the conduit itself (where exposed).
A third is in lengths greater than 6 ft. But you can exceed this if you can
show the AHJ the greater length is necessary or if it's secured at intervals of
3 ft within 12 inches of every box, cabinet, and fitting.
install Type LFNC using approved methods. Article 356 gives explicit commentary regarding
bending, bend radii, number of
bends, trimming, supporting, securing, and other facets of installation [356.24 - 356.42].
You can use
only fittings that are listed for use with LFNC [356.42]. And you can't use
angled connectors for concealed raceway installations.