De-Icer Electrical Requirements, GFCI and Controllers

A Kasco de-icer must be connected to a properly grounded, GFCI-protected circuit. Kasco voids the warranty if the unit is run on an extension cord or without GFCI protection. The means of disconnection has to be built into the fixed wiring to local and national code, which is work for a qualified electrician.

GFCI protection

The unit ships with an internal grounding conductor, and Kasco is direct about the rest: connect it to an approved GFCI-protected circuit to reduce the risk of electrical shock.

Test the GFCI on a schedule. Kasco asks for a test at installation, again after every re-installation, and monthly while the unit is running. An untested GFCI has not been shown to work.

Have an electrician handle the fixed wiring. A means of disconnection must be incorporated into the fixed wiring in accordance with local and national wiring rules. That is a code requirement on the circuit, not something the de-icer's plug satisfies on its own.

What voids the warranty

Four conditions void the Kasco de-icer warranty and two of them are electrical. Check these before you improvise a power run:

Running the de-icer on an extension cord. Kasco states this plainly in the de-icer manual and lists it as a warranty exclusion.
Running the de-icer without a GFCI control box.
Altering the unit, control box, or power cord from original shipment, or returning it for repair without the power cord. Cuts in the power cord are not covered.
Not maintaining the unit according to the maintenance schedule in the manual.

Use the factory cord at the length you need it rather than extending it. Kasco supplies D-Series cords in 25, 50, 100, 150 and 200 ft; buying the right length is the supported way to cover distance.

Thermostat and timer controllers

A de-icer does not need to run continuously all winter. Kasco offers two controllers that cut run time, and both plug into the outlet with the de-icer plugged into the controller.

	C-10 Thermostat	C-20 Timer and Thermostat
Control	Air temperature only	Timer and thermostat, both must be satisfied
Supply	Standard 120V outlet	GFCI-protected 120V outlet
Units controlled	One de-icer	One de-icer
Cord	8 ft connected power cord included	Mount at least 5 ft from open water

Mount either controller on a vertical surface, out of direct sunlight, and run it with the cover closed. Direct sun and internal heating both bias the thermostat reading. In winter, mount above the snow line.

Give it an hour before you judge it. Both controllers need at least an hour to acclimate to outdoor ambient temperature before the thermostat reads accurately.

Expect a tolerance band. Kasco puts the C-20's actual on/off point within about 2.7 degrees F of true ambient, so set a couple of degrees below freezing rather than exactly at it.

Fewer, longer cycles beat frequent short ones. That is Kasco's own guidance for efficient de-icing, so set it up that way from the start.

The C-20 is not a disconnect. Kasco states this in capitals in the manual. Unplug the controller and the equipment it controls before servicing either.

Controllers also need watching. Kasco asks for daily observation of any de-icing installation, and recommends setting the timer so at least one cycle falls when you are around to see it run.

Standing electrical safety rules

Do not enter the water while the equipment is connected or operating. Kasco does not recommend entering the water with equipment running under any circumstance.
Do not lift or drag the unit by the power cord. Use the ropes or the mount to move it.
Do not run the unit out of water. It damages the seals and creates a hazard for whoever is handling it.
Disconnect power before servicing or removing the de-icer.
Mark the open water. Kasco asks for signage, lighting, fencing or other measures as your area requires.

Verification status: The GFCI requirement and test schedule, the warranty-void conditions, the disconnection-means rule, and the controller specifications are reproduced from the Kasco de-icer, C-10 and C-20 manuals. This site previously stated that extension cords also void safety-listing coverage, cause voltage drop, and trigger nuisance GFCI tripping. Only the warranty consequence is stated by the manufacturer, so the other three claims have been removed rather than published as fact.

Data Provenance: Kasco De-Icer Operation & Maintenance Manual (Safety First, Warranty), C-10 Control Panel Manual and C-20 Timer and Temperature Control Manual.

Reviewed by: Jon — M.S. Hydrology, Principal Hydrologist, Natural Waterscapes LLC. 30+ years of field experience in aquatic thermodynamics and winter ice control.