I've just received a Grundfos condensate pump to use under the
basement dehumidifier.

The old pump (which seized up after about 6 years) had a sealed-up
cable that you could strip and use optionally to power something else
(with a cut-off if the tank gets full and fails to empty). But you
didn't have to do anything if you weren't going to use that cable.

The new one came with bare wires on both the incoming (no plug!) and
outgoing cables. As a temporary measure, I stuck Wago blocks on the
wires and a Wago box on the cable. What are some good ways to cap the
cable off? I was thinking of heat-shrink insulation on each wire, then
a piece shrunk onto the end of the cable with some excess to fold over
and then cover with another layer.

Thanks.