The National Electric Code does not require a separate disconnect switch when a breaker panel is within sight of the condensing unit and not otherwise more than 50 feet from the unit; however, some jurisdictions are more restrictive than the NEC. In my city, Corpus Christi, Texas, the city has revised NEC Section 440.11 to read as follows:
"440.11 General.
"(A) Purpose. The provisions of Part B are intended to require disconnecting means capable of disconnecting air-conditioning and refrigeration equipment, including motor-compressors and controllers from the circuit conductions.
"(B) Branch Circuits. A disconnecting means must be provided in the ungrounded conductors of each branch circuit to electrically operated air conditioning components.
"(C) Fusible Disconnect. A fusible disconnect switch must be installed for single phase air conditioning equipment of five tons rating or less.
"(D) Integrally install components. Disconnecting means must not be required on equipment with integrally installed disconnecting means."

And the initial paragraph of NEC Section 440.14 is revised to read as follows:
"440.14. Location. Disconnecting means shall be locatd within sight from, readily accessible from, and within six feet of the air-conditioning or refrigeration equipment. The disconnecting means shall be permitted to be installed on or within the air-conditioning or refrigeration equipment."

As regards the latter permitted location, I would recommend not installing a disconnect on the unit that was not intergral with the unit since most panels on a condensing unit are capable of be removed for maintenance. Also the requirement for a fused-type disconnect switch seems like an overkill for a residential unit, but that's what my city requires. These installations are inspected by the city electrical inspector and not the power company.

George E. Clower, AIA
Architect