Study guide
6.5 Feeders and Outside Branch Circuits — Articles 215 and 225
Alaska Journeyman Electrician Study Guide Exam
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1 Chapter 1: Alaska Certificates of Fitness, Law & Exam Logistics
1.1 The Alaska Certificate of Fitness System 1.2 Journeyman Eligibility: 8,000 Hours and How Alaska Counts Them 1.3 Trainee, Residential Wireman, Lineman, Provisional & Reciprocal Certificates 1.4 The Journeyman Examination: Format, Scheduling, Open-Book Rules & Retakes 1.5 Adopted Codes, Fees, Renewal, Inspection & Enforcement
2 Chapter 2: Using the 2020 NEC
2.1 Article 90: Purpose, Scope, Arrangement & Enforcement 2.2 Navigating the Code Book: Structure, Index & Tabbing Strategy 2.3 Article 100 Definitions You Must Know Cold 2.4 Electrical Theory for the Exam: Ohm's Law, Power & Three-Phase
3 Chapter 3: General Requirements — Article 110
3.1 Approval, Listing, Interrupting Rating & Terminations 3.2 Temperature Limitations of Terminations — 110.14(C) 3.3 Working Space, Access, Egress & Illumination — 110.26(A) through (D) 3.4 Dedicated Equipment Space, Guarding & Over-1000-Volt Installations
4 Chapter 4: Conductors and Ampacity — Article 310
4.1 Conductor Types, Insulation Markings & Table 310.16 4.2 Ambient Temperature Correction and Alaska's Cold 4.3 Adjustment for More Than Three Current-Carrying Conductors 4.4 Putting It Together: Full Conductor-Sizing Problems 4.5 Parallel Conductors, Dwelling Service Sizing & Conditions of Use
5 Chapter 5: Wiring Methods and Materials — NEC Chapter 3
5.1 Article 300 General Requirements and Underground Cover 5.2 Thermal Movement: Expansion Fittings and Table 352.44 5.3 Boxes and Enclosures: Box Fill and Pull Box Sizing 5.4 Cable Assemblies: NM, MC, AC, SE, UF and TC 5.5 Raceways: RMC, IMC, EMT, FMC, LFMC, PVC and ENT 5.6 Conduit Fill: Chapter 9 Tables and Annex C 5.7 Cable Trays, Wireways, Busways, Gutters and Surface Raceways
6 Chapter 6: Branch Circuits and Feeders
6.1 Branch-Circuit Ratings, Conductor Sizing & Multiwire Circuits 6.2 Required Outlets and Receptacle Spacing in Dwellings 6.3 GFCI Protection — Article 210.8 6.4 AFCI Protection and Receptacle Requirements 6.5 Feeders and Outside Branch Circuits — Articles 215 and 225 6.6 Grounded Conductor Identification, Switches & Panelboards
7 Chapter 7: Overcurrent Protection — Articles 240 and 242
7.1 Article 240 Fundamentals: Ratings, Locations & Conductor Protection 7.2 Feeder Tap Rules — 240.21(B) 7.3 Transformer Secondary Conductors — 240.21(C) 7.4 Fuses, Circuit Breakers, Series Ratings & Article 242 Surge Protection
8 Chapter 8: Services and Load Calculations
8.1 Service Conductors, Clearances and Service Equipment 8.2 Service Disconnects, the 2020 Rule Change, SPDs and Service GFPE 8.3 Article 220 Part II: General Lighting, Receptacles and Demand Factors 8.4 The Standard Dwelling Calculation — Article 220 Part III 8.5 Optional Dwelling and Multifamily Calculations 8.6 Commercial and Industrial Load Calculations 8.7 Neutral Load Calculations and Harmonics — 220.61
9 Chapter 9: Grounding and Bonding — Article 250
9.1 System Grounding, 250.24 and the Main Bonding Jumper 9.2 The Grounding Electrode System — 250.50 through 250.53 9.3 Grounding Electrode Conductor Sizing and Installation 9.4 Bonding: Services, Metal Piping, Structural Metal and Other Systems 9.5 Equipment Grounding Conductors: Types, Sizing and Continuity 9.6 Separately Derived Systems and Separate Buildings 9.7 Ground-Fault Protection of Equipment and Grounding of Specific Equipment
10 Chapter 10: Equipment for General Use — NEC Chapter 4
10.1 Flexible Cords, Cables and Fixture Wires 10.2 Switches, Receptacles and Industrial Control Panels 10.3 Luminaires, Lampholders and Recessed Installations 10.4 Appliances and Fixed Electric Space Heating 10.5 Deicing, Snow Melting, Pipeline and Vessel Heating 10.6 Motors Part I: Full-Load Current, Conductors and Overload Protection 10.7 Motors Part II: Short-Circuit Protection, Controllers, Disconnects and HVAC
11 Chapter 11: Transformers, Generators and Special Occupancies
11.1 Transformers — Article 450 11.2 Generators, Storage Batteries and Energy Storage Systems 11.3 Hazardous (Classified) Locations — Articles 500 through 506 11.4 Garages, Hangars, Fuel Dispensing, Bulk Storage and Spray Application 11.5 Health Care Facilities — Article 517 11.6 Agricultural Buildings, Manufactured Homes, RV Parks and Marinas 11.7 Assembly, Theaters, Carnivals, Temporary Installations and Pools
12 Chapter 12: Special Equipment, Special Conditions and Exam Strategy
12.1 Signs, Cranes, Elevators, Electric Vehicle Charging and Welders 12.2 Solar Photovoltaic, Interconnection and Stand-Alone Systems 12.3 Wind Electric Systems and Fire Pumps 12.4 Emergency, Legally Required Standby, Optional Standby and COPS 12.5 Class 1, 2 and 3 Circuits, Fire Alarm, Optical Fiber and Communications 12.6 Cold-Climate Practice in Alaska: Code Basis and Engineering Judgment 12.7 Exam-Day Strategy: Navigation, Calculation Workflow and Time Management
6.5 Feeders and Outside Branch Circuits — Articles 215 and 225
Key Takeaways Explain This Topic AI
NEC 215.2(A)(1) requires feeder conductors to have an ampacity not less than the noncontinuous load plus 125 percent of the continuous load, and not less than the calculated load per Article 220.
NEC 215.10 requires ground-fault protection of equipment for each feeder disconnect rated 1000 amperes or more on solidly grounded wye systems of more than 150 volts to ground but not exceeding 1000 volts phase-to-phase.
NEC 215.6 requires a feeder supplying branch circuits with equipment grounding conductors to include or provide an equipment grounding conductor to which the branch-circuit equipment grounding conductors are connected.
NEC 225.18 sets overhead conductor clearances of 10 feet, 12 feet, 15 feet, and 18 feet depending on voltage and what is below, mirroring the service clearances of 230.24(B).
NEC 225.31 and 225.32 require a disconnecting means for all ungrounded conductors supplying a building or structure, installed at a readily accessible location either outside or inside nearest the point of entrance.
Last updated: August 2026
Feeder Minimum Rating and Size — 215.2
215.2(A)(1)(a) General. Feeder conductors shall have an ampacity not less than required to supply the load as calculated in Parts III, IV, and V of Article 220 . The minimum feeder-circuit conductor size shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load .
Exception No. 1 applies where the assembly including the overcurrent devices is listed for operation at 100 percent of its rating. Exception No. 2 covers grounded conductors not connected to an overcurrent device.
215.2(A)(1)(b) Feeders Supplying Motor Loads. Sized per 430.24, 430.25, and 430.26 — covered in Chapter 10 of this guide.
215.2(A)(2) Ampacity Relative to Service Conductors. The feeder conductor ampacity shall not be less than that of the service conductors where the feeder conductors carry the total load supplied by service conductors with an ampacity of 55 amperes or less.
The Informational Note to 215.2(A) contains the feeder voltage-drop recommendation: conductors sized to prevent a voltage drop exceeding 3 percent at the farthest outlet, with the total on feeders and branch circuits not exceeding 5 percent , provide reasonable efficiency of operation. As with 210.19(A), this is a recommendation, not a mandatory rule.
Feeder Overcurrent Protection — 215.3
Feeders shall be protected against overcurrent in accordance with Part I of Article 240 . Where a feeder supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load , subject to the same 100-percent-rated-assembly exception.
Feeder Equipment Grounding — 215.6
Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide an equipment grounding conductor , in accordance with the provisions of 250.134, to which the equipment grounding conductors of the branch circuits shall be connected.
This is why a subpanel in a detached structure, or any subpanel at all, must be fed with a separate equipment grounding conductor and must have its neutral isolated from the enclosure. The neutral-to-ground bond exists only at the service or at a separately derived system — 250.142(B).
Ground-Fault Protection of Equipment for Feeders — 215.10
Each feeder disconnect rated 1000 amperes or more and installed on solidly grounded wye electrical systems of more than 150 volts to ground but not exceeding 1000 volts phase-to-phase shall be provided with ground-fault protection of equipment in accordance with 230.95.
The classic covered system is 480Y/277 V , which is 277 V to ground. A 208Y/120 V system is only 120 V to ground and is not covered regardless of ampere rating.
Three exceptions apply: where ground-fault protection is provided on the supply side of the feeder and on the load side of any transformer supplying the feeder; for fire pumps; and for feeders supplying continuous industrial processes where a non-orderly shutdown would introduce additional or increased hazards.
Feeder Identification — 215.12
215.12(A) Grounded Conductor. Identified per 200.6.
215.12(B) Equipment Grounding Conductor. Identified per 250.119.
215.12(C) Identification of Ungrounded Conductors. Where a building has feeders supplied from more than one nominal voltage system, each ungrounded conductor shall be identified by phase or line and system at all termination, connection, and splice points. The means of identification shall be documented in a manner readily available or permanently posted at each feeder panelboard or similar distribution equipment. 215.12(C)(2) requires the high leg of a 4-wire delta system to be identified per 110.15 by an orange outer finish or other effective means, and durably and permanently marked at each point of connection.
Outside Branch Circuits and Feeders — Article 225
Article 225 covers requirements for outside branch circuits and feeders run on or between buildings, structures, or poles on the premises, and electrical equipment and wiring for the supply of utilization equipment located on or attached to the outside of buildings.
Clearances — 225.18 and 225.19
225.18 Clearance for Overhead Conductors and Cables. Overhead spans of open conductors and open multiconductor cables of not over 1000 volts nominal shall have a clearance of not less than:
Clearance Applies over
10 ft Above finished grade, sidewalks, or from any platform or projection from which they might be reached, where the voltage does not exceed 150 volts to ground and the area is accessible to pedestrians only
12 ft Over residential property and driveways, and those commercial areas not subject to truck traffic, where the voltage does not exceed 300 volts to ground
15 ft For those areas listed in the 12-foot classification where the voltage exceeds 300 volts to ground
18 ft Over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property, and other land such as cultivated, grazing, forest, and orchard
24.5 ft Over track rails of railroads
225.19 Clearances from Buildings for Conductors of Not Over 1000 Volts, Nominal. (A) Above roofs — 8 feet, with the same style of reductions found in 230.24(A). (B) From nonbuilding or nonbridge structures — 3 feet. (C) Horizontal clearances — 3 feet. (D) Final spans — clearance from windows designed to be opened, doors, porches, balconies, ladders, stairs, fire escapes, and similar locations shall be not less than 3 feet.
Compare this with the service clearances in 230.24(B), which are the same set of numbers. The Code deliberately mirrors them; the difference is which article applies to the conductors in front of you.
Number of Supplies — 225.30
A building or other structure served shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (F). The permitted additional supplies cover special conditions (fire pumps, emergency systems, legally required standby, optional standby, parallel power production, systems designed for connection to multiple sources), special occupancies by special permission, capacity requirements where the capacity requirements are in excess of 2000 amperes, different characteristics such as different voltages or phases, and documented switching procedures in large industrial installations.
Disconnecting Means — 225.31 through 225.33
225.31 Disconnecting Means. Means shall be provided for disconnecting all ungrounded conductors that supply or pass through the building or structure.
225.32 Location. The disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting means shall be at a readily accessible location nearest the point of entrance of the conductors. Exceptions cover installations under single management with documented safe switching procedures, garages and outbuildings on residential property where the disconnect is suitable for the conditions, and certain towers and poles.
225.33 Maximum Number of Disconnects. The disconnecting means for each supply permitted by 225.30 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard or switchgear. There shall be no more than six disconnects per supply grouped in any one location.
Notice the difference from services: the 2020 NEC changed 230.71 to require essentially one service disconnect (with the two-to-six allowance requiring separate enclosures or compartments), while 225.33 still permits six disconnects in a single enclosure for a feeder supply to a building.
225.36 Type. The disconnecting means specified in 225.31 shall be suitable for use as service equipment . An exception permits an isolating switch for towers or poles used as lighting standards.
225.38 requires the disconnecting means to plainly indicate whether it is in the open or closed position, and 225.37 requires permanent plaques or directories where a building is supplied by more than one feeder, branch circuit, or service, denoting all other supplies and their locations.
Alaska Application: Detached Shops and Outbuildings
A very common Alaska project is feeding a detached shop, garage, or cabin from a main dwelling. The rules that converge on that job are:
- 225.30 — one feeder to the structure unless a listed exception applies;
- 225.31/225.32 — a readily accessible disconnect at the structure, nearest the point of entrance;
- 225.36 — that disconnect must be suitable for use as service equipment;
- 250.32(A) — a grounding electrode system is required at the separate structure;
250.32(B)(1) — the feeder must include an equipment grounding conductor, and the grounded conductor must not be bonded to the enclosure at the outbuilding;
300.5 and Table 300.5(A) — burial cover for the underground run;
300.5(J) — arrangement to prevent damage from frost heave and settlement.
That last item is the one that separates a durable Alaska installation from a callback. Section 9.6 of this guide works through the grounding side in detail.