|Figure 1. Relay with soldered wires. Black tubing: hot wire on pump side. Yellow tubing: 5V input from Arduino. Green tubing: ground on Arduino. Uninsulated connection: hot wire on plug side.|
Three of the connections were partially insulated with heat shrink tubing. Additional insulation with electrical tape (as well as complete insulation for the fourth connection) is needed. The lack of heat shrink tubing on the fourth connection was not intentional and should not be purposely replicated if this project were to be repeated. Figure 1 shows the relay with all soldered wires.