a power sharing device is disclosed , having a primary utility in supplying power to automotive block heaters or other auto warming devices at a user selectable duty cycle of 12 . 5 % or 25 %. in a first mode , power is supplied to 4 outlets in a sequential manner , for 15 minutes each . in a second mode , power is supplied to the 4 outlets in a sequential manner , for 7 . 5 minutes each , followed by a period of 7 . 5 minutes in which power is not supplied . the user may elect to initiate a delay period , that is selectable between 1 and 2 hours , to precede the sequence of power distribution , allowing time for the car to cool before the power cycles begin . a test circuit , activated by a pushbutton , allows a user to distinguish between the periods of time when power is not being supplied to an outlet as a part of the sequential sharing of power between outlets and a circuit malfunction , such as a blown fuse .