Elevator Feeder Wire Sizing Service Guide
// PLAN ELEVATOR FEEDERS, MACHINE-ROOM DISCONNECTS, HYDRAULIC PUMP CIRCUITS, CAB LIGHTING, AND CONTROL POWER WITH AMPACITY AND VOLTAGE-DROP CHECKS BEFORE INSPECTION. //
Elevator wiring is a vertical-transportation system problem before it is a simple motor circuit. An elevator feeder supplies the controller and drive equipment. A machine-room circuit is the power path serving controller, motor, brake, lighting, receptacles, and auxiliary equipment. Voltage drop is conductor voltage loss that can cause weak starts, controller faults, and nuisance callbacks. Start with controller data, motor horsepower or FLA, duty rating, travel distance, terminal temperature, grounding, disconnect location, and the adopted NEC or IEC rules before choosing AWG or mm2 cable.
NEC elevator scope
NEC Article 620 covers elevators, dumbwaiters, escalators, moving walks, platform lifts, and stairway chairlifts, while NEC 430 and 310 still shape motor and conductor checks.
Voltage drop target
Use 3% branch and 5% total as common NEC design targets, then tighten to 2% if the controller or manufacturer requires it.
IEC cross-check
IEC 60364-5-52 checks current-carrying capacity, installation method, grouping, ambient temperature, and voltage drop, while IEC 60228 defines metric conductor classes.
TL;DR
- Do not size an elevator feeder from breaker rating alone
- Start with controller nameplate current, motor FLA, duty, terminal temperature, and manufacturer data
- Check NEC 620 first, then coordinate NEC 430 motor rules, NEC 310 ampacity, and NEC 250 grounding
- Run voltage drop for the actual machine-room or hoistway route, especially beyond 100 ft
- Keep car lighting, receptacles, HVAC, fire alarm, and control circuits separate where the code and plans require it
Key definitions
Elevator feeder
An elevator feeder is the conductor set that supplies elevator controller or machine-room equipment from upstream distribution.
Controller
An elevator controller is the listed control equipment that manages the motor drive, brake, door operation, safety circuits, and car movement.
Voltage drop
Voltage drop is the reduction in delivered voltage caused by conductor resistance, load current, and one-way circuit length.
Sizing workflow
Step 1 - collect elevator data
Record controller input amps, motor horsepower or FLA, voltage, phase, drive type, hydraulic pump data, duty rating, and manufacturer minimum circuit ampacity if provided.
Step 2 - identify circuit types
Separate main feeder, motor branch, cab lighting, pit lighting, receptacle, HVAC, sump pump, fire alarm, and control power before selecting conductors.
Step 3 - size conductors
Use NEC 620 equipment rules with NEC 430 motor principles, NEC Table 310.16 ampacity, terminal temperature limits, and derating for raceway grouping or ambient conditions.
Step 4 - check voltage drop
Enter one-way route length, current, voltage, phase, and conductor material in the calculator. Long risers and remote machine rooms often upsize before ampacity fails.
Step 5 - coordinate inspection details
Verify disconnect location, selective coordination where required, EGC size, bonding, controller short-circuit rating, working space, fire alarm interface, and AHJ elevator inspection notes.
Worked examples
25 HP 480V traction elevator
Controller lists 40A input at 480V 3-phase, 125 ft one-way copper feeder, 75C terminals, machine room remote from switchgear.
A 40A design current may start near #8 AWG copper for ampacity, but voltage-drop review can justify #6 AWG when the owner wants about 2% running drop.
40 HP hydraulic pump elevator
Hydraulic controller shows 65A input at 208V 3-phase, 90 ft one-way, grouped raceway with other elevator auxiliary circuits.
Ampacity may point toward #4 AWG copper at 75C after adjustment, and the voltage-drop tool should compare #4 and #3 because 208V systems lose percentage margin quickly.
400V IEC lift feeder
32A lift controller, 45 m one-way, copper multicore cable in tray with grouped building services.
6 mm2 may pass in some IEC installation methods, but 10 mm2 is often reviewed when grouping and IEC 60364-5-52 voltage drop are both considered.
Elevator circuit comparison
| Circuit | Sizing basis | Likely conductor check | Voltage-drop risk | Code note |
|---|---|---|---|---|
| Main traction feeder | Controller input current and duty | #8 to #6 AWG Cu for many 40A cases | Medium beyond 100 ft | NEC 620, 430, 310 |
| Hydraulic pump feeder | Pump controller FLA or MCA | #4 to #3 AWG Cu in 60-70A cases | High at 208V | Motor starting and controller data govern |
| Cab lighting circuit | Lighting load and transformer rating | #14 or #12 AWG Cu where permitted | Low to medium | Keep separate from main power as required |
| Machine-room receptacle | 20A maintenance receptacle | #12 AWG Cu typical check | Medium on long runs | GFCI and location rules apply |
| IEC lift feeder | Design current and installation method | 6-10 mm2 depending method and drop | Medium on 30-60 m routes | IEC 60364-5-52 and IEC 60228 |
Code checkpoints
Use these references as design checkpoints, then confirm the adopted code edition, elevator manufacturer instructions, fire alarm interface, and local elevator inspector requirements.
NEC Article 620
Covers elevators, dumbwaiters, escalators, moving walks, platform lifts, stairway chairlifts, disconnects, wiring methods, and related equipment.
NEC Article 430
Motor-circuit principles still matter for motor conductors, short-circuit protection, controllers, overloads, and feeder calculations.
NEC 310 and 250
Check conductor ampacity, adjustment factors, terminal temperature, equipment grounding conductors, and bonding together.
NEC 215 and 110
Feeders, working space, equipment ratings, terminations, and installation workmanship affect the final design.
IEC 60364-5-52
IEC projects use installation method, grouping, ambient correction, current-carrying capacity, and Clause 525 voltage-drop guidance.
IEC 60228
Use metric conductor class and nominal cross-sectional area when translating between AWG and mm2 cable selections.
Field checklist
- Use controller nameplate current or manufacturer MCA where provided.
- Measure the actual one-way route through risers, machine rooms, pull boxes, and offsets.
- Check voltage drop at running load and review starting or acceleration performance separately.
- Do not combine elevator auxiliary circuits unless plans and code rules allow it.
- Verify disconnect visibility, lockable provisions, fire alarm shunt or recall interfaces, and elevator inspector notes.
- Size the equipment grounding conductor from the protective device and confirm bonding at controller and motor equipment.
- Keep calculation records with the elevator submittal, panel schedule, and inspection package.
Elevator feeder wire sizing FAQ
What wire size is used for a 40A elevator controller?
For a 40A 480V 3-phase controller, #8 AWG copper may be the ampacity starting point at suitable 75C terminals, but #6 AWG is often reviewed on a 100-125 ft run to hold voltage drop near 2-3%.
Can I size an elevator feeder from the breaker?
No. Use controller data, motor current, duty, conductor temperature, derating, and voltage drop. Motor short-circuit protection may be larger than the conductor ampacity under NEC motor logic.
What NEC article covers elevator wiring?
NEC Article 620 covers elevator and similar equipment wiring. Designers also check NEC 430, 310, 250, 215, and 110 for motor, conductor, grounding, feeder, and installation details.
Should elevator voltage drop be stricter than 3%?
Sometimes. A common design target is 3% branch and 5% total, but some controllers or specifications call for about 2% running drop or tighter startup performance review.
Does cab lighting use the same feeder as the elevator motor?
Not automatically. Cab lighting, receptacles, HVAC, fire alarm, and control power may require separate circuits or disconnecting arrangements depending on NEC 620, plans, and AHJ interpretation.
How does IEC lift sizing differ from AWG sizing?
IEC designs use mm2 conductors, installation methods, grouping factors, protective-device coordination, and IEC 60364-5-52 voltage-drop checks instead of AWG table selection alone.
Check the elevator feeder before submittal
Use the motor, voltage-drop, and ampacity tools to compare the minimum conductor with the practical size that keeps the controller stable during real operation.