Safety Low-voltage systems are easy and safe to install and use. The danger is 120-volt power and requires high attention to safety. Working on 120 volt lines can be life threatening, especially around water or moisture. Be sure that power is turned off, and check it with a power meter. If you’re not completely sure about working with electricity, hire an electrician.   For safety, install a ground fault circuit interrupter (GFCI) in each electrical outlet if you plan to use electrical power in or near waterfall. The GFCI senses any contact with water, and shut off the flow of electricity. Installing a GFCI requires professional skills. A less expensive GFCI outlet can be installed near the waterfall.   Calculate the electrical load needed to work your waterfall and all of its components. Pumps and other components are marked by number of watts or amps. Compare the needed power requirements with the number of amps or watts a circuit can handle.   Residential circuit breakers amps (current) x volts (potential) = watts (power). For the most waterfalls, a single 20-amp circuit is enough. If your power is more than 2,400, and you need 20 amps or more, install a second circuit. A l more...