Remove the new cooktop from its packaging. Remove all tape and protective plastic. Use the measuring tape to make sure the new electric cooktop will fit in the opening in your countertop.
Turn off the electricity to the electric cooktop. Check to make sure the wiring is sufficient to carry the load required by the cooktop. A Whirlpool cooktop must have three- or four-wire, single-phase 240-volt AC current supplied on a separate circuit.
Place the cooktop upside-down on the counter. Attach the clamps that hold the cooktop in place to the short sides of the cooktop. You can wait to attach these clamps after the cooktop is in place, but it’s more difficult to do.
Set the cooktop in place. Fasten the clamps to the underside of the countertop to secure the electric cooktop, using a screwdriver.
Remove the junction box cover. Match the wires with the conduit from the cooktop. Start with the black wires. Twist them together and secure them with UL-approved wire nut connectors. Continue with the two red wires. Connect the white wires next. Finish with the green or bare ground wire. Replace the junction box cover.
Wipe off any packing residue on the cooktop with a clean, damp cloth. Attach the knobs.
Turn the power back on to the cooktop. Check the burners to see if they are working. If they don’t, make sure the breakers are set properly in the breaker box.
Install a gas cooktop in a similar manner. While the electrical wiring must be in place to operate a gas cooktop as well as an electrical one, you must also have the appropriate gas connections. In most municipalities, licensed professionals must make these connections to natural gas or liquid propane gas lines in order for the appliance to pass inspection.