Detached garage panel
What's wrong here?
- Nothing. This installation is compliant
- Because this building has its own ground rods, the neutral bar must be bonded to the enclosure
- The feeder's green equipment grounding conductor must be the same size as the black and red conductors
- The grounding electrode conductor must land on the neutral bar, not the equipment grounding bar
Show the answer and the code reference
The answer
Nothing is wrong: this is a correct four-wire feeder to a separate building, with an isolated neutral, a bonded equipment grounding bar, and a grounding electrode conductor to the building's own electrodes.
Correct choice: 1. Nothing. This installation is compliant
For a separate building supplied by a feeder, 250.32(B)(1) requires an equipment grounding conductor to be run with the feeder and connected to the building disconnecting means and to the grounding electrodes. The grounded (neutral) conductor stays isolated from the enclosure and from the EGCs. 250.32(A) requires a grounding electrode system at the separate building, so the GEC leaving the panel to the rods is required, not optional, and it belongs on the EGC bar. The 10 AWG green feeder EGC is correct for a 60 A overcurrent device per Table 250.122. The 60 A main breaker serves as the building disconnecting means that 225.31 requires for a separate building.
How to fix it
No correction needed. Out at the rods, confirm the two-rod (or tested 25 ohm) requirement of 250.53(A)(2), rod spacing of at least 6 ft (250.53(A)(3)), and clamps listed for direct burial (250.70).
Code references
NEC 2023 250.32(B)(1) — Supplied by a Feeder or Branch Circuit
An EGC as described in 250.118 shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s); the grounded conductor is not to be connected to the EGC or electrodes, except for certain existing installations under Exception No. 1.
Drills citing 250.32(B)(1)NEC 2023 250.32(A) — Grounding Electrode
Buildings or structures supplied by feeders or branch circuits shall have a grounding electrode or grounding electrode system installed per Part III of Article 250, unless only a single branch circuit with an EGC supplies the structure.
Drills citing 250.32(A)NEC 2023 Table 250.122 — Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment
Sizes EGCs by the rating of the overcurrent device ahead of the circuit; 60 A requires 10 AWG copper.
Drills citing Table 250.122
2026 NEC:not yet checked Confidence: low
Minnesota
Minnesota adopts the NEC as published, with no section-by-section amendments (Minn. Stat. 326B.35; Minn. Rules 1315.0200), so 250.32 and Table 250.122 read the same as in the 2023 NEC. The 2023 NEC governs permits filed from July 1, 2023 until the 2026 NEC took effect; for newer permits, check the section numbers in the 2026 edition. Detached garages are common in Minnesota housing stock, and older three-wire bonded feeders are often found; those are allowed to remain only under the conditions in 250.32(B)(1) Exception No. 1.
How Minnesota adopts the NECWhy the other choices are wrong
- Because this building has its own ground rods, the neutral bar must be bonded to the enclosure. 250.32(B)(1) requires an EGC with the feeder and forbids connecting the neutral to the EGC or electrodes at the separate building; the old three-wire bonded method survives only for existing installations.
- The feeder's green equipment grounding conductor must be the same size as the black and red conductors. EGCs are sized by the overcurrent device under Table 250.122; a 60 A feeder needs only 10 AWG copper.
- The grounding electrode conductor must land on the neutral bar, not the equipment grounding bar. At a feeder-supplied building with an EGC, the electrodes connect to the EGC bar and enclosure; landing the GEC on the neutral would create a prohibited neutral-to-ground bond.