26 mm 2 (10 AWG) ground wire must be used, and in all other markets a 6 mm 2 must be used. Equipment grounding conductor (EGC) sizes for copper and aluminum wiring, from NEC Table 250. 122, but understanding how to apply these requirements correctly can make the difference between a safe installation and a costly code violation. Grounding of the units: Attach a ground wire from one of the threaded studs (A) at the bottom of the housing, to the mounting plate (B). Attach a second grounding wire from the mounting. The NEC specifies exact ground wire sizes based on the circuit breaker rating, and using undersized ground wire is both a code violation and a serious safety hazard. A 100-amp breaker needs a #8 AWG.
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