"Both USE-2 and PV wire can be directly buried without the need for extra protection per NEC. However, some photovoltaic cables are not rated for direct burial, and it is best to check with the manufacturer before installing.
What is buried contact solar cell?
The buried contact solar cell is a high efficiency commercial solar cell technology based on a plated metal contact inside a laser-formed groove.
Are buried contact solar cells better than screen-printed solar cells?
The buried contact technology overcomes many of the disadvantages associated with screen-printed contacts and this allows buried contact solar cell to have performance up to 25% better than commercial screen-printed solar cells. A schematic of a buried contact solar cell is shown in the figure below.
Does buried contact solar cell reduce emitter resistance?
As shown in the Emitter Resistance page, the emitter resistance is reduced in a buried contact solar cell since a narrower finger spacing dramatically reduces the emitter resistance losses.
Metal conduit. The question would be whether photovoltaic wire (what IS the proper name, if not "MC"?) can be used inside conduit. It is already water proof, but not intended for direct burial. It's extra thick insulation might mean in a cable, bundle, conduit it would need further derating.
Can you use use-2 in ungrounded photovoltaic arrays?
"You cannot use USE-2 in ungrounded photovoltaic arrays; this is the task that only PV wire can handle because service entrance cables can only be used in grounded systems." If that refers not to ungrounded frames, but rather neither PV- nor PV+ being grounded, it would rule out USE-2 for many PV systems.
If that refers not to ungrounded frames, but rather neither PV- nor PV+ being grounded, it would rule out USE-2 for many PV systems. Arrays used to be required to be grounded (but were often only grounded through a 1A fuse which would blow as part of GFCI function), but now many are ungrounded (all transformerless GT PV systems.)