The Double-Tapped Panel and the Hot Bonus Room
At a 2001 house, the inspector opens a 200-amp main panel in the garage. A 20-amp breaker has two 12-gauge copper conductors under one terminal screw; the panel label does not list the breaker for two conductors. A 30-amp breaker feeds a 12-gauge conductor to a garage receptacle circuit. Two unused openings in the panel cover are missing knockout fillers. In the upstairs bonus room over the garage, the supply register reads 92°F and the return reads 73°F after 20 minutes of operation; the room is 80°F while the outdoor temperature is 90°F. The filter is new. The attic insulation over the bonus room is compressed to about 5 inches of fiberglass; the bath fan discharges into the attic. The furnace is an 80% AFUE, 100,000 BTU/h unit. The buyer asks if the room is “just hot because it’s upstairs” and whether the electrical items are “minor.”
1. How should the electrical findings be reported, and what is the risk of the 30-amp breaker with 12-gauge wire?
Read the worked answer
Report all three electrical findings as safety issues, not “minor.” The double-tapped 20-amp breaker is a defect because the breaker is not labeled for two conductors; the connection can loosen and overheat. The 30-amp breaker protecting 12-gauge wire is a serious overcurrent mismatch-12-gauge copper is generally limited to a 20-amp breaker for this type of circuit-so the wire can overheat before the breaker trips. Missing knockout fillers leave open panel openings and invite foreign objects or fingers. Recommend a licensed electrician evaluate and correct. Reasoning: the inspector should not remove or repair conductors, but should describe the hazard, location, and why it matters. Do not call them “minor” just because the panel is in a garage. If the inspector cannot determine the circuit’s purpose, say so and recommend electrician tracing.
2. How should the inspector evaluate the bonus-room comfort issue, and what should be recommended?
Read the worked answer
Treat the bonus room as a system problem, not “just upstairs.” A 19°F supply-to-return temperature split shows the air handler is producing cooling, but the room remains 80°F, so the issue is likely distribution or enclosure: duct leakage or poor duct insulation in the garage/attic, compressed insulation (about 5 inches of fiberglass is roughly R-15 to R-19, below typical current levels), and bath fan discharge into the attic adding moisture. Report the measurements, insulation depth, and fan termination; recommend an HVAC contractor evaluate airflow/ducts and a qualified insulation/ventilation contractor evaluate the attic. Reasoning: the inspector can identify likely causes and performance gaps but cannot determine the exact fault without further testing. Avoid promising that more insulation alone will fix it; the duct location and attic ventilation need evaluation.