Re: gfci
The NEC does not have any requirements to have any Ground-Fault Circuit Interrupter (GFCI) protection for fixed outdoor electric deicing and snow-melting equipment, but ground-fault protection of equipment (GFPE) is required as stated in Section 426.28.
426.28 Equipment Protection.
Ground-fault protection of equipment shall be provided for fixed outdoor electric deicing and snow-melting equipment, except for equipment that employs mineral-insulated, metal-sheathed cable embedded in a noncombustible medium.
Article 100 defines Ground-Fault Circuit Interrupter and Ground-Fault Protection of Equipment, which are as follows:
Ground-Fault Circuit Interrupter. A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device.
FPN: Class A ground-fault circuit interrupters trip when the current to ground has a value in the range of 4 mA to 6 mA. For further information, see UL 943, Standard for Ground-Fault Circuit Interrupters.
Ground-Fault Protection of Equipment. A system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit. This protection is provided at current levels less than those required to protect conductors from damage through the operation of a supply circuit overcurrent device.
The UL white book, (2000 GENERAL INFORMATION DIRECTOPY page 29), states that Ground-Fault Protection of Equipment is intended for use in applications where ground fault protection of equipment is required by the NEC, specifically Section 426.28 and 427.22, or where such protection is deemed appropriate.
So in answer to your question: (do you need gfci for de-iceing equimpent,when it's a dedicated circuit. Outside) you are required to install Ground-Fault Protection of Equipment and there are no exceptions if the circuit is dedicated.