Electrical Systems
Service and grounding
Start at the service drop. Typical overhead clearances are 10 feet above a sidewalk or balcony, 12 feet above a driveway, 18 feet above a public street, and 3 feet from a window. Look for a drip loop, a secure mast and a weatherhead. Grounding and bonding are frequent question topics: the grounding electrode conductor runs to a rod, a metal water pipe with at least 10 feet of soil contact, or a concrete-encased electrode. Metal water and gas piping must be bonded, but gas piping may never serve as the grounding electrode.
Panels
Look for double-tapped breakers not listed for two conductors, breakers oversized for the wire (14 AWG on a 20-amp breaker), rust or water staining, scorching, missing knockout fillers, missing deadfront screws and an unlabeled panel. Aluminum branch-circuit wiring and fuse panels holding oversized fuses are reportable.
Devices and protection
Remember the receptacle spacing rule: no point along a wall line may be more than 6 feet from a receptacle, which yields 12-foot maximum spacing, and every doorway must be within 6 feet of one. Kitchen counter receptacles so that no point is more than 24 inches from one. GFCI protection is expected in bathrooms, kitchens, garages, exteriors, laundry areas and unfinished basements; AFCI protection in bedrooms. Test GFCIs and report any that will not trip or reset.
Worked example
A 20-amp breaker protecting 14-gauge copper conductors is a mismatch - the wire's ampacity is 15 amps. Report the condition and recommend correction by a licensed electrician rather than reciting a code section.