Grounding Conductor Calculator for Vermont
NEC 2020 grounding conductor math for EV charger installers working in Vermont.
EGC sizing in Vermont follows NEC 2020 Table 250.122, indexed off the upstream OCPD rating, with parallel rules for parallel sets and increased-conductor adjustments under 250.122(B).
Worked example for Vermont
For a 200 A EVSE branch, Table 250.122 calls for a minimum #6 Cu equipment grounding conductor. If you upsize the phase conductors for voltage drop in Vermont's long runs, NEC 250.122(B) requires the EGC to be upsized proportionally.
Code & Utilities
Vermont currently enforces the NEC 2020 edition, adopted in 2022. That includes Article 625 (Electric Vehicle Power Transfer System) requirements: 125% continuous-load sizing on EVSE branch circuits, GFCI protection at outdoor receptacles, and provisions for energy management systems on shared circuits.
In Vermont, you'll most often interconnect with Green Mountain Power, Vermont Electric Cooperative, Burlington Electric Department. Each has its own service-upgrade timeline, EV rebate availability, and metering rules — confirm them before quoting commercial work.
Climate & Ampacity
In Vermont, the 84°F summer ambient drives a 0.94× 75°C ampacity correction. Bake this into every Level 2 and DCFC conductor pick before you commit to a wire size. The correction is mild but still NEC-required; document it on the load calc so your inspector sees that 310.15(B) was applied.
Vermont takeaway
On DCFC sites with parallel feeder sets, each parallel raceway needs its own full-size EGC — a detail inspectors in Vermont catch frequently on commercial submittals.