ICC ECS cheat sheet

The ICC Electrical Code (ICC ECS) is a companion to the International Building Code; where the two conflict, the more restrictive provision governs.

Section 90-style scope rule: installations, materials, and equipment must be listed and labeled by an approved agency for the specific use; unlisted field-modified equipment is a violation.

Working clearance at electrical equipment follows the 110.26 pattern: 30 in wide, 36 in deep, 6 ft 6 in high, with depth increased to 36/42/48 in by nominal voltage and exposed live parts on the opposite side.

Overcurrent protection rule: conductors must be protected at their ampacity; the next-higher standard rating is permitted only when the conductor ampacity does not exceed 800 A and the next size up does not exceed the load.

Grounding vs. bonding distinction: grounding establishes a reference to earth; bonding connects metal parts to ensure fault-current path continuity. Both are required at service equipment.

GFCI protection is required in bathrooms, garages, outdoors, kitchens (countertop receptacles), laundry areas, and within 6 ft of sinks; AFCI protection is required for branch circuits supplying dwelling-unit bedrooms and similar occupancies.

Receptacle spacing in dwelling units: no point along the floor line of a wall space may be more than 6 ft from a receptacle outlet; wall spaces 2 ft or wider require a receptacle.

Temporary wiring and construction-site power require GFCI protection for all 125-V, single-phase, 15- and 20-A receptacle outlets, and must be removed when construction is complete.

Inspection sequence: rough-in inspection before concealment, then final inspection after finish work; concealed work without rough-in approval must be exposed for inspection.

A permit is required for new electrical work, alterations, and replacements of equipment; ordinary repair or replacement of lamps, fuses, or snap switches does not require a permit.

Plan review submittals must include load calculations, service and feeder sizing, grounding electrode system, and a one-line diagram for services above the threshold set by the jurisdiction.

Service load calculation: use the standard method (general lighting at 3 VA/sq ft for dwellings) or the optional method; the calculated load determines the service disconnecting means rating.

The service disconnecting means must be rated at least the calculated load and located at a readily accessible point nearest the point of entry of the service conductors, either outside or inside nearest the entry.

Feeder and service conductor sizing uses Table 310.16 ampacities with adjustment for ambient temperature and conductor count in a raceway; more than three current-carrying conductors in a raceway requires derating.

Voltage-drop guidance (informational, not mandatory in most editions): keep total drop to 3% on a branch circuit and 5% on feeder plus branch combined.

Correction notice procedure: the inspector issues a written notice citing the code section; work may not be concealed or energized until the cited item is corrected and reinspected.

Certificate of occupancy or final approval is withheld until all electrical inspections pass and all correction notices are cleared.

Nonmetallic-sheathed cable (NM-B) is permitted in dwellings and similar structures but is prohibited in hazardous locations, in raceways outdoors, and where subject to physical damage.

Rigid metal conduit, intermediate metal conduit, and electrical metallic tubing require support within 3 ft of boxes and every 10 ft thereafter; EMT requires support within 3 ft of termination and every 10 ft.

Box fill calculation: count each conductor entering the box, add one for each yoke/device, add for equipment grounding conductors, then compare to the box volume in cubic inches from Table 314.16(B).

Conductor identification: grounded conductor must be white or gray; equipment grounding conductor must be green, green with yellow stripe, or bare; ungrounded conductors may be any other color.

Cable and raceway entries into boxes require approved connectors; unused openings in boxes, cabinets, and enclosures must be closed with listed plugs or plates.

Junction boxes must be accessible; splices and taps must be made in an approved enclosure and cannot be buried in walls or ceilings.

Wet and damp locations require listed weatherproof boxes, covers, and gaskets; receptacles in wet locations require an enclosure that maintains weatherproof integrity with the attachment plug inserted.

Conductor ampacity adjustments: ambient temperature correction factors apply above 30 degrees C; bundling more than three current-carrying conductors requires derating per the adjustment table.

Dwelling general lighting load is 3 VA per square foot; small-appliance branch circuits require at least two 20-A circuits, and laundry requires at least one 20-A circuit.

Standard calculation demand factors: first 3,000 VA of general lighting and receptacle load at 100%, from 3,001 to 120,000 VA at 35%, and above 120,000 VA at 25%.

Range and dryer demand factors follow Table 220.55; a single range up to 12 kW may be calculated at 8 kW demand.

Optional method for dwellings: use the larger of 100% of noncoincident loads plus 40% of other loads, with the minimum service rating never less than 100 A for a single-family dwelling.

Branch circuit ratings: 15-A circuits for general lighting, 20-A for small-appliance and laundry, 20-A minimum for bathroom receptacles, and 30-A or 50-A for specific appliances per nameplate.

Multioutlet receptacle loads in non-dwellings are calculated at 180 VA per outlet, with demand factors applied per Table 220.44.

Service-entrance conductors must have ampacity not less than the calculated load and must be sized to the service disconnecting means rating.

Neutral conductor sizing: the grounded conductor may be smaller than the ungrounded conductors where the calculated maximum unbalanced load permits, but never smaller than the required minimum.

Grounding electrode system: a metal underground water pipe in contact with earth for 10 ft or more, a concrete-encased electrode, a ground ring, and made electrodes; where a water pipe is used it must be supplemented by another electrode.

The grounding electrode conductor is sized from Table 250.66 based on the largest ungrounded service conductor; the equipment grounding conductor is sized from Table 250.122 based on the overcurrent device rating.

Main bonding jumper connects the grounded service conductor to the equipment grounding conductor at the service; it must be removed or omitted at subpanels to keep the grounded conductor isolated.

Bonding of metal water piping, gas piping, structural steel, and other metallic systems is required to the grounding electrode system using listed bonding jumpers.

Standard overcurrent device ratings: 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200 A and upward in standard steps.

Fuse and breaker selection: the device rating must not exceed the conductor ampacity, except the next-higher standard rating allowance for loads of 800 A or less.

Series-rated systems require the combination of the line-side and load-side devices to be listed as a series combination; field substitution of a different breaker type voids the rating.

Ground-fault protection of equipment (GFPE) is required for solidly grounded wye services over 150 V to ground and more than 1,000 A.

Hazardous location classification: Class I (flammable gases/vapors), Class II (combustible dust), Class III (ignitable fibers); each divided into Division 1 or 2 or Zones 0, 1, 2 under the zone system.

Equipment in classified locations must be marked with the class, division or zone, and group; the marking must match the area classification exactly.

Swimming pools: all 15- and 20-A, 125-V receptacles within 20 ft of the pool edge require GFCI protection; underwater luminaires require specific bonding and grounding.

Health care facilities require redundant grounding and equipotential grounding in patient care areas, plus hospital-grade receptacles with a green dot marking.

Motor circuits: overload protection protects the motor, branch-circuit short-circuit and ground-fault protection protects the conductors; the motor branch-circuit device may be sized up to 250% of the motor full-load current for inverse-time breakers.

Motors require a disconnecting means within sight of the motor and controller, and the disconnecting means must be capable of being locked in the open position.

Fire pump circuits must be protected against overload but not against short circuit in a way that would disconnect power during a fire; the overcurrent device must be sized to carry locked-rotor current indefinitely.

Solar photovoltaic systems require rapid shutdown provisions, DC conductor marking, and disconnecting means at the point of interconnection; the inverter output circuit is sized at 125% of continuous output current.

The code official has authority to interpret the code, approve alternate materials and methods, and require tests to verify compliance; alternate approvals must be recorded in writing.

Where the ICC ECS and manufacturer instructions differ, the more restrictive requirement applies; listed equipment must be installed per its listing and labeling.

Existing installations that complied when installed may remain, but new work must meet current requirements; a change of occupancy may trigger a full compliance evaluation.

Appeals of code official decisions go to the board of appeals within the jurisdiction's stated time frame, typically 20 to 30 days after the decision.

Unsafe or noncompliant installations may be disconnected or ordered out of service by the code official with written notice to the owner and occupant.

Stop-work orders may be issued where work proceeds without a permit or in violation of the approved plans; work must cease until the order is rescinded.

The code is not retroactive, but the code official may require correction where an existing condition constitutes a distinct hazard to life or property.

Definitions control enforcement: 'approved' means acceptable to the code official, 'listed' means included in a published list by an approved agency, and 'labeled' means bearing the listing mark.