CFR > Title 46 - Shipping > CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY > SUBCHAPTER J—ELECTRICAL ENGINEERING (parts 110 to 113) > PART 111—ELECTRIC SYSTEMS—GENERAL REQUIREMENTS > SUBPART 111.05—Equipment Ground, Ground Detection, and Grounded Systems (§111.05-1 to §111.05-37) > 111.05-31—Grounding conductors for systems.

111.05-31—Grounding conductors for systems.

(a) A conductor for grounding a direct-current system must be the larger of:
(1) The largest conductor supplying the system; or
(2) No. 8 AWG (8.4mm 2 ).
(b) A conductor for grounding the neutral of an alternating-current system must meet Table 111.05-31(b).
Table 111.05-31(b)—Neutral Grounding Conductor for Alternating-Current System
Size of the largest generator cable or equivalent for parallel generators—AWG-MCM (mm2) Size of the system grounding conductor—AWG(mm2)
Greater than Less than or equal to
2 (33.6) 8 (8.4)
2 (33.6) 0 (53.5) 6 (13.3)
0 (53.5) 3/0 (85.0) 4 (21.2)
3/0 (85.0) 350 MCM (177) 2 (33.6)
350 MCM (177) 600 MCM (304) 0 (53.5)
600 MCM (304) 1100 MCM (557) 2/0 (67.5)
1100 MCM (557) 3/0 (85.0)