What do electricians wrap around wires to keep them from getting wet?

Air
why would an electrician consider water or humidity. He would not. The idea would not occur. This is why a wet sauna has the controls outside. This is why only a waterproof off kill switch is on the inside of a wet sauna.
electrical tape is what you asked
There are intense reasons an electrician is worth his weight in gold. One slip and you die with electrical tape. This does not become allowed his way.