A bolt heater including a junction housing, a handle attached and secured to a wall of the housing solely from an exterior of the housing, such as by a threaded connection, a power cable including a fitting attached directly to the wall of the housing, and an electrical resistance heater rod attached to the wall of the housing. The wall may have a boss with a recess therein for receiving a portion of the handle. The housing may be a hollow cylinder with a circular top wall, a circular bottom wall, and a cylindrical side wall. The heater rod may be attached to the housing via a threaded connection and the housing may have a non-circular portion near the threaded connection point, the non-circular portion being engageable by a tool to assist in the threading attachment of the heater rod to the housing.