6.1 Service Entrance Conductors & Clearances
Key Takeaways
- Service conductors run from the service point to the service disconnect; service-entrance conductors are the portion between the service drop/lateral/underground conductors and the service equipment terminals (Art. 100 / Art. 230)
- NEC 230.9(A) requires not less than 3 ft clearance from service conductors to openable windows, doors, porches, fire escapes, and similar locations (with listed exceptions)
- NEC 230.24(B) vertical clearances to final grade are commonly 10 ft, 12 ft, 15 ft, or 18 ft depending on location and voltage-to-ground — open the table/section; do not invent heights
- Service-entrance conductor ampacity must meet 230.42 (including continuous-load sizing) and each service drop/lateral generally supplies only one set of service-entrance conductors per 230.40 (exceptions exist)
- Overhead terminations need a service head and drip loops per 230.54 so water cannot enter raceways or equipment
Why Service Conductors Matter on the Arkansas JW Exam
The Arkansas Journeyman Electrician exam (Prov / ADLL, NEC 2023, 60 questions, 3 hours, 70% pass) weights Service, Feeders, Branch Feeders and Overcurrent Protection at 8 items. A large share of those stems land in Article 230. This section covers service-conductor identity, clearances, and service-entrance conductor rules. Disconnects, working space, and the service grounding bond are covered in §§6.2–6.4.
On an open-book form, Prov will not ask you to recite poetry from memory — but you will lose time if you cannot tell a service drop from a service lateral, or if you confuse service conductors with feeders. Tab Article 230 Parts I–IV, 230.9, 230.24, 230.40, 230.42, and 230.54 before exam day.
Service Vocabulary (Article 100 + Article 230)
Learn these definitions cold so the stem language matches the right Part of Article 230:
| Term | Practical meaning |
|---|---|
| Service point | Connection between premises wiring and the serving utility |
| Service conductors | Conductors from the service point to the service disconnecting means |
| Service drop | Overhead service conductors from last pole/support to the building (utility side language often) |
| Service lateral | Underground service conductors from the street/main to the building |
| Service-entrance conductors | Conductors between the terminals of the service equipment and the service drop, overhead service conductors, service lateral, or underground service conductors |
Exam trap: meter sockets are often on the service conductor path, but the service disconnect — not the meter — is the boundary that ends “service conductors” for many Article 230 rules. Read the stem’s exact term.
Clearance from Building Openings (230.9)
230.9(A) requires service conductors installed as open conductors or multiconductor cable without an overall outer jacket to maintain not less than 3 feet from windows that are designed to be opened, doors, porches, balconies, ladders, stairs, fire escapes, or similar locations.
Exceptions matter on Prov items:
- Conductors run above the top level of a window are generally permitted (they are not “in front of” the opening in the same way).
- Clearance rules interact with how the conductors are installed (open vs cable/raceway). If the stem says “open conductors near an openable window,” start at 230.9, not at feeder rules in Article 215.
Quick check: 2 ft from an openable window is almost always wrong when 230.9(A)’s 3 ft rule applies. 3 ft is the number to verify in the book under time pressure.
Vertical Clearances — Overhead Service Conductors (230.24)
230.24 is a high-frequency lookup. Do not memorize every inch from a blog; open the section and match the location + voltage-to-ground.
Above roofs — 230.24(A)
Overhead service conductors generally need 8 ft vertical clearance above roofs, measured from the roof surface. Important published exceptions (verify exact text in your NEC):
- Roofs with a slope of 4 in 12 or greater may allow reduced clearance (commonly 3 ft in the exception language).
- Overhangs of limited depth and voltage may allow further reductions for conductors attached above the roof overhang.
If the stem gives roof slope, you are being pointed at the exception path, not the base 8 ft rule alone.
Clearance from ground — 230.24(B)
Classic grade clearances you will verify in 230.24(B):
| Situation (paraphrased — confirm in Code) | Typical minimum |
|---|---|
| Areas accessible to pedestrians; circuits ≤150 V to ground (e.g., many 120/240 V residential sidewalks) | 10 ft |
| Residential property and driveways; commercial areas not subject to truck traffic (within voltage limits stated) | 12 ft |
| Same areas as the 12 ft row, but voltage exceeds 300 V to ground | 15 ft |
| Public streets, alleys, roads, parking areas subject to truck traffic, nonresidential driveways, other areas traversed by vehicles | 18 ft |
Prov pattern: “Residential driveway” → look for 12 ft under 230.24(B), not the 18 ft street rule. “Public street / truck traffic” → 18 ft.
Also remember 230.26: the point of attachment of overhead service conductors to a building must be not less than 10 ft above finished grade and located so the 230.9 and 230.24 clearances can be maintained. The drip loop’s lowest point must also respect the clearance scheme — attachment height is not a free-for-all.
Underground Service Conductors (Part III)
Underground service conductors (including laterals) are covered in Article 230 Part III. Exam themes:
- Protect conductors against physical damage where they emerge and where subject to disturbance.
- Seal raceways where moisture/gas can enter buildings (coordinate with Chapter 3 sealing rules when the stem mentions conduit into a building).
- Burial depths are often controlled by Table 300.5 (wiring methods), not invented “service-only” numbers — if the stem asks cover depth, open Table 300.5 for the wiring method and location column.
Do not call underground service conductors “feeders.” Feeders start on the load side of the service disconnect.
Number of Sets of Service-Entrance Conductors (230.40)
230.40 general rule: each service drop, set of overhead service conductors, set of underground service conductors, or service lateral shall supply only one set of service-entrance conductors.
Exceptions (you must open them when the stem describes multiple disconnects or multiple occupancies) allow additional sets in defined cases — including arrangements that align with the two-to-six service disconnect permissions in 230.71(B). Exam skill: if the stem says “one service lateral feeding six grouped disconnects,” you are in the exception + 230.71 world, not inventing a free-for-all.
Ampacity and Continuous Loads (230.42)
230.42 requires service-entrance conductors to have adequate ampacity for the loads served. The continuous-load path is the same logic you use elsewhere: size for 125% of continuous load + 100% of noncontinuous load unless an exception applies (for example, where assembly ratings allow otherwise under the section’s conditions).
Workflow on Prov:
- Identify continuous vs noncontinuous loads in the stem.
- Apply 230.42 sizing.
- Select conductors using Table 310.16 (and 110.14(C) termination temperature limits) — services still obey termination temperature rules.
- Do not use feeder demand results from Article 220 as a substitute for reading 230.42 when the question specifically asks service-entrance conductor ampacity rules.
Minimum service sizes for dwellings also interact with 230.79 disconnect ratings (covered in §6.2). Conductor ampacity and disconnect rating are related but not identical questions — answer the asked piece.
Service Heads and Drip Loops (230.54)
230.54 is a favorite “installation detail” item:
- Service raceways and cables must be equipped with a service head (weatherhead) or gooseneck of a type listed for wet locations, as applicable.
- Conductors must be arranged to form drip loops, and connections arranged so water will not enter service raceway or equipment.
- Service-entrance cable must be supported within the distances stated in the section; service heads must be located above the point of attachment of the service-drop or overhead service conductors (verify exact wording).
If a stem shows water entering a meter or panel from overhead conductors, the Code cure is drip loops + weatherhead arrangement — not a larger breaker.
Timed Open-Book Tips for §6.1
- Tab 230.9, 230.24, 230.40, 230.42, 230.54 as a cluster.
- On clearance items, first classify: opening (230.9) vs grade/roof (230.24) vs attachment height (230.26).
- On conductor identity items, ask: has the service disconnect been passed yet? If yes, you may already be in feeder territory.
- Never apply Article 225 outside feeder/branch outside-building rules when the stem clearly says service.
Per NEC 230.9(A), what is the minimum clearance generally required between open service conductors and an openable window?
Under NEC 230.24(B), which vertical clearance above grade is the typical minimum for overhead service conductors over a residential driveway (within the section’s voltage limits)?
What is the general rule in NEC 230.40 regarding how many sets of service-entrance conductors a service drop or service lateral may supply?
Why does NEC 230.54 require drip loops at overhead service connections?