The core Thermorail range comes with multiflex wiring which allows for both exposed and concealed wiring. Exposed wiring means the cable comes out of the leg and plugs directly into a power outlet. This can then be operated with a plugin timer or using the on/off switch. The concealed wiring cable runs into the wall and can be wired to a timer or external switch. There is no issue with the towel rail being operated only on a switch or plugged into a power outlet and this does not affect the warranty of the towel rail. A timer is not required on a Thermorail heated towel rail for warranty purposes.