A dimmer switch module removably connects to a wiring module mounted within an electrical box and connected to a power source. The dimmer switch module is configured to control electrical current flowing from the power source to a power sink, such as a light. The dimmer switch module has a front cover and a back cover housing a circuit board. A dimmer control is accessible on the front cover. Shielded plugs are disposed on the back cover and are configured to mate with corresponding structured sockets of a wiring module so as to electrically connect to a power source routed to the wiring module. A power control element mounted on the circuit board is responsive to the dimmer control so as to vary the amount of electrical current flowing between the shielded plugs.