Karl Townsend wrote:

I hit an underground 12-3 wire with my shovel digging a hole. Gouged it
right up to the wire on one conductor.

I think cutting the wire in two and putting in an underground splice may
cause more trouble than it fixes.

Just wrapping the spot with electrical tape will probably let water in and
it will fail here in the future.

Is there a another repair option?

If the copper is not damaged you could use
electrical tape to repair the insulation of
that conductor. Apply more tape all around
the cable, I would use at least a double layer.
Next get from out of the kitchen an aluminum
pie plate and wrap that around the repair, but
leave the top open for the moment. Get hold of
some old candles and melt them in a soup can.
Pour the molten wax in the open top of the
wrapped pie plate and then fold the top closed.
Optionally use some cable ties. HTH.
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Have 5 nice days! John
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