Russell Swindell Sr.
Electrical Licenses Exam Prep & Continuing Ed
ARTICLE 230 SERVICES
230.6 Conductors Considered Outside the Building.
Conductors shall be considered outside of a building or
other structure under any of the following conditions:
(1) Where installed under not less than 50 mm (2 in.) of
concrete beneath a building or other structure
(2) Where installed within a building or other structure in a
raceway that is encased in concrete or brick not less
than 50 mm (2 in.) thick
(3) Where installed in any vault that meets the construction
requirements of Article 450, Part III
(4) Where installed in conduit and under not less than 450
mm (18 in.) of earth beneath a building or other struc-
ture
(5) Where installed within rigid metal conduit (Type
RMC) or intermediate metal conduit (Type IMC) used
to accommodate the clearance requirements in 230.24
and routed directly through an eave but not a wall of a
building.
[ROP 4–103]
230.7 Other Conductors in Raceway or Cable.
Conduc-
tors other than service conductors shall not be installed in
the same service raceway or service cable.
Exception No. 1: Grounding electrode conductors and
equipment bonding jumpers or conductors.
[ROP 4–105]
Exception No. 2: Load management control conductors
having overcurrent protection.
230.8 Raceway Seal.
Where a service raceway enters a
building or structure from an underground distribution sys-
tem, it shall be sealed in accordance with 300.5(G). Spare
or unused raceways shall also be sealed. Sealants shall be
identified for use with the cable insulation, shield, or other
components.
I. General
230.2 Number of Services.
A building or other structure
served shall be supplied by only one service unless permit-
ted in 230.2(A) through (D). For the purpose of 230.40,
Exception No. 2 only, underground sets of conductors, 1/0
AWG and larger, running to the same location and con-
nected together at their supply end but not connected to-
gether at their load end shall be considered to be supplying
one service.
(A) Special Conditions.
Additional services shall be per-
mitted to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of
supply for the purpose of enhanced reliability
(B) Special Occupancies.
II. Overhead Service Conductors
230.22 Insulation or Covering.
Individual conductors
shall be insulated or covered.
Exception: The grounded conductor of a multiconductor
cable shall be permitted to be bare.
230.23 Size and Rating.
(A) General.
Conductors shall have sufficient ampacity to
carry the current for the load as calculated in accordance
with Article 220 and shall have adequate mechanical
strength.
(B) Minimum Size.
The conductors shall not be smaller
than 8 AWG copper or 6 AWG aluminum or copper-clad
aluminum.
Exception: Conductors supplying only limited loads of a
single branch circuit — such as small polyphase power,
controlled water heaters, and similar loads — shall not be
smaller than 12 AWG hard-drawn copper or equivalent.
(C) Grounded Conductors.
The grounded conductor shall
not be less than the minimum size as required by
250.24(C).
230.24 Clearances.
Overhead service conductors shall not
be readily accessible and shall comply with 230.24(A)
through (E) for services not over 1000 volts, nominal.
[ROP 4–108]
(A) Above Roofs.
Conductors shall have a vertical clear-
ance of not less than 2.5 m (8 ft) above the roof surface.