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ARTICLE 250 GROUNDING AND BONDING 70-110R
NATIONAL ELECTRICAL CODE
2005 Edition
ARTICLE 250 GROUNDING AND BONDING

250.118 Types of Equipment Grounding
Conductors. The equipment grounding conductor
run with or enclosing the circuit conductors shall be
one or more or a combination of the following:
(1)

A copper, aluminum, or copper-clad aluminum
conductor. This conductor shall be solid or
stranded; insulated, covered, or bare; and in
the form of a wire or a busbar of any shape.
(2)

Rigid metal conduit.
(3)

Intermediate metal conduit.
(4)

Electrical metallic tubing with an additional
equipment grounding conductor.
(5)

Listed flexible metal conduit with an
additional equipment grounding conductor,
and meeting all the following conditions:
a.

The conduit is terminated in fittings listed
for grounding.
b.

The combined length of flexible metal
conduit and liquidtight flexible metal
conduit in the same ground return path
does not exceed 1.8 m (6 ft) for feeders
and 15 m (50 ft) for branch circuits.
c.

The additional equipment grounding
conductor is terminated at each
termination or junction point.
(6)

Listed liquidtight flexible metal conduit
meeting all the following conditions:
a.

The conduit is terminated in fittings listed
for grounding.
b.

For metric designators 12 through 16
(trade sizes 3/8 through 1/2), the circuit
conductors contained in the conduit are
protected by overcurrent devices rated at
20 amperes or less.
c.

For metric designators 21 through 35
(trade sizes 3/4 through 11/4), the circuit
conductors contained in the conduit are
protected by overcurrent devices rated not
more than 60 amperes and there is no
flexible metal conduit, flexible metallic
tubing, or liquidtight flexible metal
conduit in trade sizes metric designators
12 through 16 (trade sizes 3/8 through
1/2) in the grounding path.
d.

The combined length of flexible metal
conduit and flexible metallic tubing and
liquidtight flexible metal conduit in the
same ground return path does not exceed
1.8 m (6 ft).
e.

Where used to connect equipment where
flexibility is necessary after installation,
an equipment grounding conductor shall
be installed.
(7)

Listed liquidtight flexible metal conduit with
an additional equipment grounding conductor
and meeting all of the following conditions:
a.

The conduit is terminated in fitting listed
for grounding.
b.

The combined length of liquidtight
flexible metal conduit and flexible metal
conduit in the same ground return path
does not exceed 15 m (50 ft) for branch
circuits and 1.8 m (6 ft) for feeders.
c.

The additional equipment grounding
conductor is terminated at each
termination or junction point.

(8) Flexible metallic tubing where the tubing is
terminated in fittings listed for grounding and
meeting the following conditions:
a.

The circuit conductors contained in the
tubing are protected by overcurrent
devices rated at 20 amperes or less.
b.

The combined length of flexible metal
conduit and flexible metallic tubing and
liquidtight flexible metal conduit in the
same ground return path does not exceed
1.8 m (6 ft).
(9)

Armor of Type AC cable with an additional
equipment grounding conductor and as
provided in 320.108.
(10)

The copper sheath of mineral-insulated, metal-
sheathed cable.
(11)

Type MC cable where listed and identified for
grounding in accordance with the following:
a. The combined metallic sheath and
grounding conductor of interlocked metal
tapetype MC cable
c.

The metallic sheath or the combined
metallic sheath and grounding conductors
of the smooth or corrugated tube type MC
cable.
(12)

Cable trays as permitted in 392.3(C) and
392.7.
(13)

Cablebus framework as permitted in 370.3.
(14)

Other listed electrically continuous metal
raceways and listed auxiliary gutters.
(15)

Surface metal raceways listed for grounding.