NEC Article 230 Services, Service Conductors, Service Equipment,
Disconnecting Means, Service Entrance Conductors, Service
Raceway Installation, Grounding and Bonding, Load Management
Conductors, Service Identification, Number of Services Rules,
Special Occupancies, Fire Pumps, Emergency Systems, Standby
Systems, Parallel Power Systems, Capacity Requirements, Voltage
Frequency Phase Separation, Service Clearances, Underground
Distribution Systems, Raceway Sealing Requirements, Service
Conductor Restrictions, Overcurrent Protection Coordination,
Service Equipment Enclosures, Utility Service Interface, Service
Entrance Rules, Building Electrical Supply Systems, One Service Per
Building Rule, Multi-Service Exceptions, Service Conductors Routing
Prohibitions, Service Vault Installations, RMC IMC Installation
Methods, NEC 300.5 Compliance, NEC 230.2 Applications, NEC 230.9
Clearance Standards, NEC 230.6 Underground Conductors, NEC
230.7 Raceway Conductors Limitations, NEC 230.8 Sealing
Standards, NEC 230.3 Structural Wiring Separation, NEC 110
Equipment Requirements, AHJ Approval Standards Exam Questions
Verified and Provided with Complete A+
230.1 Scope.
This article covers service conductors and equip- ment for control and protection of services
and their installa- tion requirements.
Part I. General 230.2 Number of Services.
A building or other structure served shall be supplied by only one service unless permitted 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 connected together at
,their supply end but not connected together at their load end shall be considered to be
supplying one service.
230.2 Number of Services. (A) Special Conditions.
Additional services shall be permitted 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 supply for the purpose of enhanced
reliability
Part I. General 230.2 Number of Services. (B) Special Occupancies
By special permission, additional services shall be permitted for either of the following: (1)
Multiple-occupancy buildings where there is no available space for service equipment
accessible to all occupants (2) A single building or other structure sufficiently large to make
two or more services necessary
230.2 Number of Services.(C) Capacity Requirement
Additional services shall be permitted under any of the following:
1) Where the capacity requirements are in excess of 2000 amperes at a supply voltage of 1000
volts or less
2) Where the load requirements of a single-phase installa- tion are greater than the serving
agency normally supplies through one service
,3) By special permission
230.2 Number of Services. (D) Different Characteristics.
Additional services shall be permitted for different voltages, frequencies, or phases, or for
different uses, such as for different rate schedules.
230.2 (E) Identification.
Where a building or structure is supplied by more than one service, or any combination of
branch circuits, feeders, and services, a permanent plaque or directory shall be installed at
each service disconnect location denoting all other services, feeders, and branch circuits
supplying that building or structure and the area served by each. See 225.37.
230.3 One Building or Other Structure Not to Be Supplied Through Another.
Service conductors supplying a building or other structure shall not pass through the interior
of another building or other structure.
230.6 Conductors Considered Outside the Building.
Conduc- tors 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.) thíck
, 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 structure
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
230.7 Other Conductors in Raceway or Cable.
Conductors other than service conductors shall not be installed in the same service raceway
or service cable in which the service conductors are installed.
Exception No. 1: Grounding electrode conductors or supply side bond- ing jumpers or
conductors shall be permitted within service raceways.
Exception No. 2: Load management control conductors having overcur- rent protection shall
be permitted within service raceways.
230.8 Raceway Seal.
Where a service raceway enters a building or structure from an underground distribution
system, it shall be sealed in accordance with 300.5(G). Spare or unused race- ways shall also
be sealed. Sealants shall be identified for use with the cable insulation, shield, or other
components.
230.9 Clearances on Buildings.
Service conductors and final spans shall comply with 230.9(A). (B), and (C).
230.9 (A) Clearances.
Disconnecting Means, Service Entrance Conductors, Service
Raceway Installation, Grounding and Bonding, Load Management
Conductors, Service Identification, Number of Services Rules,
Special Occupancies, Fire Pumps, Emergency Systems, Standby
Systems, Parallel Power Systems, Capacity Requirements, Voltage
Frequency Phase Separation, Service Clearances, Underground
Distribution Systems, Raceway Sealing Requirements, Service
Conductor Restrictions, Overcurrent Protection Coordination,
Service Equipment Enclosures, Utility Service Interface, Service
Entrance Rules, Building Electrical Supply Systems, One Service Per
Building Rule, Multi-Service Exceptions, Service Conductors Routing
Prohibitions, Service Vault Installations, RMC IMC Installation
Methods, NEC 300.5 Compliance, NEC 230.2 Applications, NEC 230.9
Clearance Standards, NEC 230.6 Underground Conductors, NEC
230.7 Raceway Conductors Limitations, NEC 230.8 Sealing
Standards, NEC 230.3 Structural Wiring Separation, NEC 110
Equipment Requirements, AHJ Approval Standards Exam Questions
Verified and Provided with Complete A+
230.1 Scope.
This article covers service conductors and equip- ment for control and protection of services
and their installa- tion requirements.
Part I. General 230.2 Number of Services.
A building or other structure served shall be supplied by only one service unless permitted 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 connected together at
,their supply end but not connected together at their load end shall be considered to be
supplying one service.
230.2 Number of Services. (A) Special Conditions.
Additional services shall be permitted 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 supply for the purpose of enhanced
reliability
Part I. General 230.2 Number of Services. (B) Special Occupancies
By special permission, additional services shall be permitted for either of the following: (1)
Multiple-occupancy buildings where there is no available space for service equipment
accessible to all occupants (2) A single building or other structure sufficiently large to make
two or more services necessary
230.2 Number of Services.(C) Capacity Requirement
Additional services shall be permitted under any of the following:
1) Where the capacity requirements are in excess of 2000 amperes at a supply voltage of 1000
volts or less
2) Where the load requirements of a single-phase installa- tion are greater than the serving
agency normally supplies through one service
,3) By special permission
230.2 Number of Services. (D) Different Characteristics.
Additional services shall be permitted for different voltages, frequencies, or phases, or for
different uses, such as for different rate schedules.
230.2 (E) Identification.
Where a building or structure is supplied by more than one service, or any combination of
branch circuits, feeders, and services, a permanent plaque or directory shall be installed at
each service disconnect location denoting all other services, feeders, and branch circuits
supplying that building or structure and the area served by each. See 225.37.
230.3 One Building or Other Structure Not to Be Supplied Through Another.
Service conductors supplying a building or other structure shall not pass through the interior
of another building or other structure.
230.6 Conductors Considered Outside the Building.
Conduc- tors 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.) thíck
, 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 structure
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
230.7 Other Conductors in Raceway or Cable.
Conductors other than service conductors shall not be installed in the same service raceway
or service cable in which the service conductors are installed.
Exception No. 1: Grounding electrode conductors or supply side bond- ing jumpers or
conductors shall be permitted within service raceways.
Exception No. 2: Load management control conductors having overcur- rent protection shall
be permitted within service raceways.
230.8 Raceway Seal.
Where a service raceway enters a building or structure from an underground distribution
system, it shall be sealed in accordance with 300.5(G). Spare or unused race- ways shall also
be sealed. Sealants shall be identified for use with the cable insulation, shield, or other
components.
230.9 Clearances on Buildings.
Service conductors and final spans shall comply with 230.9(A). (B), and (C).
230.9 (A) Clearances.
