There are many things that the inspector will look for during the rooftop electrical inspection. This inspection should be scheduled when the following items are ready:

• All HVAC units, chillers, exhaust fans, make-up air units, refrigeration units and associated equipment should be installed. This includes all wires pulled to all equipment and terminated at each end.
• All required rooftop equipment maintenance receptacles installed and located within 25 feet from the equipment requiring servicing as per NEC^® 210.63(A). These receptacles cannot be connected to the load side of the equipment’s branch-circuit disconnecting means.
• All rooftop electrical boxes properly supported and electrical penetrations through the roof sealed.
• If conductors are field installed from a disconnect switch added by the electrician, through the actual HVAC unit to an internal wiring compartment (with a knockout), some inspectors will require them to be in a raceway. It is common for an inspector to find open wiring (without a raceway) installed by the electrician from the load side of the disconnect switch, through a chase nipple, and running through the condensing unit or heat pump housing where they could be exposed to rain via the open louvers in the metal or from the open grate on top for a condenser fan. Just because there are factory installed conductors without a raceway in this area of the HVAC unit doesn’t mean that the electrician can do the same with field installed branch circuits. The existing factory installed open wiring was present when the unit was tested by the Nationally Recognized Testing Laboratory (NRTL) such as Underwriters Laboratories (UL). Any additional field installed wiring was not part of the test procedure when the unit received its listing label.
• Disconnect switches for rooftop equipment (equipped with a motor) should be installed within sight of the equipment they serve.
• Disconnect switches should be labeled as to what they control unless the purpose is evident.
• Working space in accordance with NEC^® 110.26(A) will be required for each disconnecting means if the inspector feels the equipment is likely to be examined or serviced while energized.
• All rooftop exhaust fan motors should be either factory equipped with thermal overload protection (check the motor nameplate to verify) or separate overload protection should be provided by the electrician.

Below is a preview of the NEC^® (NFPA 70). See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the edition of the NEC^® being enforced.

NEC 210.63 Heating, Air-Conditioning, and Refrigeration Equipment Outlet. A 125-volt, single-phase, 15- or 20-ampere-rated receptacle outlet shall be installed at an accessible location for the servicing of heating, air-conditioning, and refrigeration equipment. The receptacle shall be located on the same level and within 7.5 m (25 ft) of the heating, air-conditioning, and refrigeration equipment. The receptacle outlet shall not be connected to the load side of the equipment disconnecting means.