Plan Review: Tenant Panel Location, Working Space, and a Continuous-Duty Espresso Machine
You are reviewing plans for a 1,400 sq ft coffee shop tenant build-out. The 208Y/120 V, three-phase tenant panel is a 24-circuit, 100 A main-breaker panel rated 22 kAIC, shown on the rear wall of a 5 ft x 8 ft storage room that also contains a mop sink and metal shelving. The panel working space is dimensioned 30 in wide x 36 in deep x 6 ft 6 in high. The panel is mounted so the center of the grip of the highest breaker handle is 6 ft 8 in above the finished floor. Shelving is drawn 12 in to the left of the panel and also directly above the panel within 3 ft of its top. The espresso machine is 208 V, three-phase, nameplate 42 A, marked for continuous duty, and is shown on a dedicated 60 A circuit with 6 AWG THWN copper in EMT. Available fault current at the service is 22,000 A.
1. Evaluate the working space and dedicated equipment space shown on the plans.
Read the worked answer
Working space dimensions - pass: 36 in depth (condition 1, 151-600 V to ground), 30 in width (equal to or greater than the equipment width if the panel is 30 in or narrower; if the panel is wider than 30 in, the width must increase to the equipment width), 6 ft 6 in height. All three are satisfied as dimensioned.
Working space use - fail: the working space may not be used for storage of any kind. A mop sink and shelving inside the 30 in x 36 in footprint is a violation, and it is also a practical hazard: wet mop water at the base of an energized panel. The plans must show the working space clear and the equipment relocated.
Dedicated equipment space - fail: the dedicated space above and below the panel, extending from the floor to 6 ft above the top of the equipment (or the structural ceiling, whichever is lower) and equal to the width and depth of the equipment, must be reserved for electrical equipment. Shelving drawn directly above the panel within 3 ft of its top violates this. Only equipment associated with the electrical installation may be in that space - no storage, no shelving, no plumbing (the mop sink supply and drain lines are also foreign piping in that zone).
Is the storage room itself a prohibited location? No. Overcurrent devices are prohibited in clothes closets, bathrooms, and similar spaces; a storage room is permitted provided the working space and dedicated space stay clear. That is precisely what fails here.
2. Evaluate the panel mounting height and accessibility.
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Fail. The maximum height for the center of the grip of the operating handle, in its highest position, is 6 ft 7 in above the floor or working platform. The plans show 6 ft 8 in, which is 1 in over the limit.
Why it matters in practice rather than as a nitpick: a person standing at the panel must be able to reach and operate the top breaker without a ladder or a chair. In a coffee shop the panel will be operated by staff, not electricians.
Correction: lower the panel by at least 1 in (and preferably more for ease of use) and re-check the bottom-most breaker's clearance from the floor and the bending space for the feeder conductors entering the enclosure. Lowering the panel also interacts with the mop sink conflict - relocating the panel entirely is the cleanest fix.
Also confirm the panel is readily accessible - not blocked by shelving, not behind a locked door that only the manager holds, and not in a location that requires climbing over stored goods.
3. Check the espresso machine branch circuit.
Read the worked answer
Continuous duty requires 125%.
- Load: 42 A x 1.25 = 52.5 A
- Conductors: 6 AWG Cu at 75°C = 65 A >= 52.5 A -> acceptable.
- Overcurrent device: must be at least 52.5 A; the next standard rating is 60 A -> the 60 A breaker shown is correct (65 A conductor ampacity >= 60 A device, so the conductor is protected).
Additional checks the plan must survive:
- Three-pole breaker - a three-phase machine on a common trip, not three singles.
- Disconnect - a hardwired appliance needs a means to disconnect; the breaker may serve if it is within sight, otherwise a local disconnect is required.
- Terminal temperature - verify the machine's terminal rating; if the nameplate specifies 60°C terminations, the 6 AWG ampacity drops to 55 A, which still passes but with almost no margin.
- Panel capacity - a 42 A three-phase load in a 100 A panel is a large share of the bus; confirm the calculated tenant load (lighting, receptacles, water heater, refrigeration, HVAC) plus 52.5 A does not exceed the 100 A bus and the feeder.
- Interrupting rating - the panel is 22 kAIC and available fault current is 22,000 A. The margin is zero; any change to the service transformer or utility configuration will void it. Flag it for the owner and consider fully rated equipment with headroom.
- GFCI - not required for a hardwired three-phase appliance, but any 125 V receptacles on the counter for the grinder or POS still need the required protection.