Electrical Tape Alone is Not Good Enough

I fixed up a new water pump and UV light to clear the water.  I used an extension wire and strip the wires and twisted the copper together and tape it up with electrical insulation tape.  It rained and the circuit breaker tripped.  I got an electric shock while troubleshooting the water pump.  So I took out the tape and strong burn smell hits me.  I found the wires are all burnt.  So water must have entered.  I have to cut out all the burnt wires and re-stripped them and twist them together again.  However, this time, I use the electrical connectors from Canada.  I hope it last longer.  With the connectors, the seal is much better.