from circuits of a different power source. Acceptable methods shall be by clamping, routing, or equivalent means that ensure permanent total separation. Where circuits of different power sources cross, the external jacket of the nonmetallic-sheathed cables shall be deemed adequate separation.
(4) Ground Connections. Ground connections to the chassis or frame shall be made in an accessible location and shall be mechanically secure. Ground connections shall be by means of copper conductors and copper or copper-alloy terminals of the solderless type identified for the size of wire used. The surface on which ground terminals make contact shall be cleaned and be free from oxide or paint or shall be electrically connected through the use of a cadmium, tin, or zinc-plated internal/external- toothed lockwasher or locking terminals. Ground terminal attaching screws, rivets or bolts, nuts, and lockwashers shall be cadmium, tin, or zinc-plated except rivets shall be permitted to be unanodized aluminum where attaching to aluminum structures.
The chassis-grounding terminal of the battery shall
be connected to the unit chassis with a minimum 8 AWG
copper conductor. In the event the unbonded lead from
the battery exceeds 8 AWG, the bonding conductor size shall be not less than that of the unbonded lead.
(D) Battery Installations. Storage batteries subject to the provisions of this Code shall be securely attached to the unit and installed in an area vaportight to the interior and ventilated directly to the exterior of the unit. Where batteries are installed in a compartment, the compartment shall be ventilated with openings having a minimum area of 1100 mm 2 (1.7 in. 2) at both the top and at the bottom. Where compartment doors are equipped for ventilation, the openings shall be within 50 mm (2 in.) of the top and bottom. Batteries shall not be installed in a compartment containing spark- or flame-producing equipment.
(E) Overcurrent Protection.
(1) Rating. Low-voltage circuit wiring shall be protected by overcurrent protective devices rated not in excess of the ampacity of copper conductors, in accordance with Table 552.10(E)(1).
Table 552.10(E)(1) Low-Voltage Overcurrent Protection
Wire Size (AWG) Ampacity
Wire Type
18 6 Stranded only
16 8 Stranded only
14 15 Stranded or solid
12 20 Stranded or solid
10 30 Stranded or solid
(2) Type. Circuit breakers or fuses shall be of an approved type, including automotive types. Fuse holders shall be clearly marked with maximum fuse size and shall be protected against shorting and physical damage by a cover or equivalent means.
FPN: For further information, see ANSI/SAE J554-1987,
Standard for Electric Fuses (Cartridge Type); SAE J1284-
1988, Standard for Blade Type Electric Fuses; and UL 275-
1993, Standard for Automotive Glass Tube Fuses.
(3) Appliances. Appliances such as pumps, compressors, heater blowers, and similar motor-driven appliances shall be installed in accordance with the manufacturer's instructions.
Motors that are controlled by automatic switching or by latching-type manual switches shall be protected in accordance with 430.32(B).