|NEC Article 250 Page 1 of 6
The following definitions were added to Article 250:
Current Path. An intentionally constructed, permanent, low-impedance path
designed and intended to carry fault current from the point of a line-to-case
fault on a wiring system to the grounded (neutral) at the electrical supply
source, see 250.4(A)(5). Figure 250-1
Author's Comment: An effective
ground-fault current path is created when all electrically conductive materials
that are likely to be energized are bonded together and to the grounded
(neutral) at the electrical supply. Effective bonding is accomplished through
the use of equipment grounding conductors, bonding jumpers, metallic raceways,
connectors and couplings, metallic sheathed cable and cable fittings, and other
approved devices recognized for the purpose. A ground-fault path is effective
when it is properly sized so that it will safely carry the maximum ground-fault
current likely to be imposed on it.
Intent: The addition of these
definitions will be very helpful for the Code user to understand the performance
requirements contained in Article 250. Defining the words or terms will help the
users more readily understand the requirements of Article
Ground-Fault. A ground-fault is an unintentional electrical
connection between an ungrounded (hot) conductor and metal enclosures, raceways,
equipment, or earth. Figure 250-2
Ground-Fault Current Path. An
electrically conductive path from the point of a line-to-case fault on a wiring
system through conductors, equipment, or the earth extending to the grounded
(neutral) terminal at the electrical supply source.
ground-fault current paths could consist of equipment grounding conductors,
metallic raceways, metallic cable sheaths, electrical equipment, and other
electrically conductive material such as metallic water and gas piping, steel
framing members, stucco mesh, metal ducting, reinforcing steel, shields of
communications cables, or the earth itself.
Author's Comment: It was
not the intent of this rule to apply to multiwire branch circuits, because a
multiwire branch circuit is considered as one circuit . However, many will
take the opportunity to apply this rule to multiwire circuits.
© 2003 Mike Holt Enterprises,Inc.