Case: the panel upgrade that failed inspection on working clearance
In one paragraph
A new C-10 replaces a 100-amp panel with a 200-amp meter-main in the same spot on the side of a 1958 house, does clean work, and fails the final because the water heater platform the homeowner built two years earlier leaves 27 inches in front of the new equipment instead of the 36 the code requires. The utility will not reconnect without the inspector's release, the house is on a generator for three days, and the fix is a relocation that was visible at the site visit. The names are invented; the dimensions come from the code.
The rule
Working space in front of equipment operating at 0 to 150 volts to ground is at least 3 feet deep in every condition, at least 30 inches wide or the width of the equipment, and clear from the floor to 6.5 feet or the height of the equipment, measured from the exposed live parts or the enclosure front (2025 CEC 110.26(A)(1)-(3)); the California amendments except only the height requirement for existing dwellings with service equipment or panelboards up to 200 amperes, never the depth. Permitted work remains exposed until approved (89.108.4.4).
Why it matters
The depth rule is the most-failed line item on residential service upgrades, and it is the one thing on the whole job you can measure with a tape at the estimate. The case is about the tape measure, the utility's sequence, and the sentence that should have been on the options sheet.