Elevator feeder wire sizing is not a simple breaker-to-wire chart lookup. The elevator controller, traction motor or hydraulic pump motor, brake, cab lighting, ventilation, receptacles, sump pump, and machine-room equipment can each trigger a different code rule. A safe design starts with the elevator supplier data, then checks conductor ampacity, disconnect rating, short-circuit protection, voltage drop, grounding, and working clearances before the feeder is released for installation.
TL;DR
- Use the elevator manufacturer nameplate and controller schedule before selecting conductor size.
- NEC Article 620 governs elevator installations; NEC Article 430 still matters for motor logic.
- Check branch and feeder voltage drop near 3% and 5% design targets on long risers.
- Size the equipment grounding conductor from the overcurrent device, then upsize if phase conductors are upsized.
An elevator feeder is a power circuit that supplies elevator equipment through a disconnecting means and controller. A machine room is the dedicated space that contains elevator driving-machine equipment, controllers, disconnects, or related controls. Voltage drop is the reduction in voltage between the service equipment and elevator terminals under load. Those definitions matter because the same 50A breaker can mean a different conductor decision when the machine room is 30 feet from the switchboard versus 240 feet above it.
The main U.S. reference is the National Electrical Code, especially NEC Article 620 for elevators, dumbwaiters, escalators, moving walks, platform lifts, and stairway chairlifts. Designers also coordinate with motor rules in Article 430 and conductor ampacity in NEC Table 310.16. For international work, compare the same engineering checks against the International Electrotechnical Commission framework, especially IEC 60364 conductor sizing and protective-device coordination. The American Wire Gauge system then gives the practical conductor size language used by most North American installers.
Start With The Elevator Load Schedule
Ask for the elevator power data sheet before pricing wire. A typical schedule will list voltage, phase, full load amps, starting current or drive input current, recommended disconnect size, maximum fuse or breaker size, and separate branch circuits for cab lighting or machine-room receptacles. Do not replace that schedule with a generic horsepower table unless the manufacturer data is missing and the engineer of record accepts a conservative assumption.
In a practical review for a 4-stop hydraulic elevator, we checked a 480V, 3-phase pump unit listed at 42A input current with a 70A maximum overcurrent device and a 180-foot one-way feeder from the service room. The first ampacity pass landed near 4 AWG copper at 75 C terminals, but the voltage-drop check moved the design to 3 AWG copper so the controller stayed within the supplier tolerance during pump start. That one-size change was cheaper than re-pulling a riser after inspection.
Elevator feeders are where I stop treating motor horsepower as the answer. A 42A controller on a 180-foot 480V run can pass NEC Table 310.16 and still justify 3 AWG copper once voltage drop and starting behavior are reviewed.
Comparison Table: Elevator Circuit Decisions
Use this table as a decision map before entering numbers in the calculator. The exact conductor size still depends on insulation, terminal temperature, raceway count, ambient temperature, and manufacturer instructions.
| Elevator Circuit | Typical Load Basis | Primary Code Check | Common Wire-Sizing Risk | Practical Example |
|---|---|---|---|---|
| Traction elevator feeder | Controller input amps and drive data | NEC 620 plus Article 430 coordination | Starting or regenerative drive behavior ignored | 55A input on 208V may need 4 AWG or larger after voltage drop |
| Hydraulic pump feeder | Pump motor/control nameplate | NEC 620.61 disconnect and 430 motor logic | Long riser sized only from ampacity | 42A at 480V over 180 ft often moves from 4 AWG to 3 AWG copper |
| Cab lighting circuit | Lighting and ventilation VA | NEC 620.22 branch-circuit requirements | Shared circuit used where a dedicated circuit is required | 120V, 15A or 20A branch circuit checked at 12 AWG for 20A |
| Machine-room receptacle | Service receptacle rating | NEC 620.23 and GFCI rules where applicable | Omitted or routed with elevator power without coordination | 20A, 120V receptacle branch circuit commonly uses 12 AWG copper |
| Equipment grounding conductor | Feeder overcurrent device | NEC 250.122 | Phase conductors upsized but EGC not proportionally reviewed | 70A OCPD starts at 8 AWG copper EGC, then review upsizing rule |
| Fire service or shunt trip controls | Control transformer and alarm interface | NEC 620.51 and local elevator/fire requirements | Control wiring mixed with power without listing separation | Class 2 control wiring may be 18 AWG but routing rules still control |
Run The Ampacity Check First
Start with conductor ampacity at the terminal temperature actually allowed by the equipment. Many elevator disconnects and controllers are evaluated using 75 C terminals for larger conductors, but smaller equipment may force a 60 C termination basis. Select from NEC Table 310.16, then apply correction and adjustment under NEC 310.15 if the elevator feeder shares a raceway with other current-carrying conductors or passes through a hot mechanical penthouse.
Example: a 208V, 3-phase traction elevator controller lists 52A input current and a 90A maximum dual-element fuse. If the conductor ampacity needs to clear the controller load at 75 C, 6 AWG copper at 65A might look acceptable before correction. If four or more current-carrying conductors share the raceway and ambient correction applies, the effective ampacity can drop below the needed value, pushing the feeder toward 4 AWG copper before voltage drop is even discussed.
Do Not Skip Manufacturer Limits
Elevator controllers often have a maximum fuse or breaker size. The conductor can be larger for voltage drop, but the overcurrent device cannot exceed the equipment listing or the engineer-approved protection schedule.
Then Check Voltage Drop And Starting Performance
The NEC voltage-drop notes are informational, but the field problem is real: long elevator feeders can make controllers fault, contactors chatter, or pump motors start poorly. A common design target is about 3% on the branch circuit and 5% total for feeder plus branch. For elevators, many engineers choose a tighter project target if the manufacturer voltage tolerance is narrow.
For a 480V, 3-phase, 42A hydraulic elevator at 180 feet one way, a rough copper voltage-drop check is: volts drop equals 1.732 x current x conductor resistance x distance. Using 4 AWG copper at about 0.000321 ohm per foot, the estimate is 1.732 x 42 x 0.000321 x 180, or about 4.2V. That is 0.9% at 480V during running current. If the controller draws much higher current during start, the supplier may still ask for a larger conductor or a drive setting review.
My cutoff is simple: if an elevator feeder is above 150 feet, I calculate voltage drop before I discuss final conduit fill. A conductor that saves $200 in copper can cost far more if a controller sees undervoltage during a loaded pump start.
Coordinate Disconnects, Grounds, And Raceway Fill
NEC Article 620 has specific disconnecting-means rules, and the disconnect location must be coordinated with elevator service access, lockability, and emergency operation requirements. The feeder conductors must fit the selected lugs and raceway, and the equipment grounding conductor must be sized from NEC 250.122 based on the overcurrent device. If ungrounded conductors are upsized for voltage drop, review the proportional equipment grounding conductor upsizing rule in NEC 250.122(B).
Raceway and pull planning can be as important as ampacity. A 3 AWG copper, 3-phase feeder with ground may fit easily in one conduit size and become a difficult pull in another, especially in a tall riser with offsets. Before issuing drawings, check the conduit fill calculator, then verify long-pull layout with the pull box sizing calculator. For load and conductor comparisons, use the main wire gauge calculator and the voltage drop calculator.
Worked Examples
Example 1: 480V Hydraulic Elevator Feeder
The elevator schedule lists 42A input, 480V 3-phase, 70A maximum overcurrent protection, 75 C terminals, and a 180-foot one-way feeder. A first ampacity pass may allow 4 AWG copper depending on installation conditions. Voltage drop at running current is under 1%, but the contractor should still confirm starting current and drive tolerance with the supplier. If the manufacturer requests tighter start performance or the feeder shares a hot riser, 3 AWG copper is a practical upgrade.
Example 2: 208V Traction Elevator In A Mid-Rise Building
A traction elevator controller lists 52A input at 208V, with an 80A fused disconnect and a 210-foot feeder. Ampacity may point toward 4 AWG copper after adjustment, but voltage drop is more sensitive at 208V. At this distance, check 3 AWG and 2 AWG copper options. A design that keeps running voltage drop below 3% leaves more margin for acceleration current and utility voltage variation.
Example 3: Cab Lighting And Machine-Room Receptacle
The elevator feeder does not eliminate separate branch-circuit requirements. A 120V, 20A cab lighting or machine-room receptacle circuit commonly uses 12 AWG copper, but the route length still matters. At 140 feet, a 16A continuous lighting load may justify upsizing to 10 AWG while the breaker remains 20A.
Common Design Mistakes
- Using elevator horsepower instead of the controller input current and manufacturer protection data.
- Forgetting NEC 620 branch-circuit requirements for cab lighting, receptacles, ventilation, and controls.
- Checking NEC Table 310.16 but ignoring terminal temperature, rooftop heat, or conductor-count derating.
- Upsizing phase conductors for voltage drop without reviewing NEC 250.122(B) for the equipment grounding conductor.
- Leaving pull boxes, disconnect working space, or conduit fill until after the wire size is already ordered.
A 20A cab lighting circuit and an 80A elevator feeder do not belong in the same mental bucket. NEC 620 splits these loads for a reason, and the cleanest submittals show each branch circuit, disconnect, and grounding conductor as its own calculation.
Frequently Asked Questions
What NEC article covers elevator feeder wire sizing?
NEC Article 620 is the main elevator article, but it does not stand alone. Most projects also need NEC 430 for motor-related logic, NEC 310.16 for conductor ampacity, NEC 250.122 for equipment grounding conductors, and NEC 110.14(C) for terminal temperature limits.
What wire size is typical for a 70A elevator feeder?
A 70A elevator feeder often starts near 4 AWG copper at 75 C terminals, but the final answer depends on the controller load, overcurrent device, correction factors, and distance. A 180-foot run may justify 3 AWG copper for voltage-drop margin even when 4 AWG passes ampacity.
Should elevator feeder voltage drop be limited to 3%?
A 3% branch-circuit and 5% total feeder-plus-branch design target is common, though the NEC treats those notes as informational in many applications. Elevator suppliers may require a tighter voltage range, so verify the controller tolerance on long 208V or 480V feeders.
Can I use aluminum conductors for elevator feeders?
Aluminum conductors can be acceptable when the equipment lugs are listed for aluminum, the terminations are prepared correctly, and voltage drop is checked. Because aluminum has higher resistance than copper, a 70A feeder that works as 4 AWG copper may need a larger aluminum conductor.
How is the elevator equipment grounding conductor sized?
Size the equipment grounding conductor from NEC 250.122 using the feeder overcurrent device. For example, a 70A overcurrent device commonly points to an 8 AWG copper equipment grounding conductor, then NEC 250.122(B) must be reviewed if phase conductors were upsized for voltage drop.
Do elevator cab lights need a separate circuit?
Yes, NEC 620 includes dedicated branch-circuit requirements for elevator car lighting, receptacles, auxiliary lighting, and ventilation. A common 120V, 20A branch circuit uses 12 AWG copper, but long runs may need 10 AWG while the breaker remains 20A.
Which calculator should I use first for an elevator feeder?
Start with the wire gauge calculator for ampacity, then run the voltage drop calculator using the actual one-way distance. Finish with conduit fill and pull box checks before ordering conductors, especially on risers longer than 100 feet.
Next Steps
Elevator wiring needs a coordinated submittal, not a single wire-size guess. Enter the manufacturer input amps, voltage, phase, conductor material, terminal temperature, and one-way distance in the calculator. Then confirm disconnect limits, grounding, conduit fill, and branch-circuit requirements before material release. For a broader motor workflow, compare this article with the motor circuit wire sizing guide and the voltage drop vs ampacity guide.
For project-specific support, use the elevator feeder wire sizing service page or contact us with your elevator schedule.
elevator feeder wire sizing: Field Verification Table
Before you close out elevator feeder wire sizing, it helps to cross-check the same five items that inspectors and experienced installers review in the field: load basis, breaker protection, voltage drop, derating, and grounding or enclosure space. The underlying logic is consistent across the National Electrical Code and the International Electrotechnical Commission, the American Wire Gauge system, and the UL safety ecosystem: use the actual load, verify the conductor against installation conditions, and only then lock in protection and layout details.
| Design Check | What to Verify | Practical Number | Typical Code Reference | Best Tool or Follow-Up |
|---|---|---|---|---|
| Load Basis | Start from nameplate load, calculated load, or connected VA before picking a conductor. | Continuous loads are usually checked at 125%. | NEC 210.19(A)(1) and 215.2(A)(1) | Use the main wire gauge calculator for the first pass. |
| Breaker Match | Protect the conductor ampacity instead of assuming the breaker sets wire size by itself. | 16A continuous becomes a 20A conductor check. | NEC 240.4 and 240.6(A) | Compare against the breaker sizing guide before trim-out. |
| Voltage Drop | Long runs often require larger wire even when ampacity already passes. | Design target is about 3% branch and 5% feeder plus branch. | NEC informational notes to 210.19 and 215.2 | Run a second check in the voltage drop calculator. |
| Derating | Account for ambient temperature, rooftop heat, and more than three current-carrying conductors. | 90 C insulation may still terminate on a 75 C or 60 C limit. | NEC 310.15 and Table 310.16 | Confirm with the ampacity calculator before ordering wire. |
| Grounding and Fill | Check equipment grounds, conduit fill, and box space as separate calculations. | A 60A feeder often uses a 10 AWG copper EGC under NEC 250.122. | NEC 250.122, 314.16, and Chapter 9 | Cross-check the ground wire and conduit fill guides before inspection. |
“If a circuit will run for 3 hours or more, I treat the 125% continuous-load check as non-negotiable. A 16A design current turning into a 20A conductor decision is exactly the kind of detail that prevents nuisance heat and callbacks.”
“Once branch-circuit voltage drop gets close to 3%, I stop debating and price the next conductor size. Moving from 12 AWG to 10 AWG on a 120V run is usually cheaper than troubleshooting low-voltage performance later.”
“The breaker, phase conductor, and equipment ground are related, but they are not the same calculation. I may upsize a 60A feeder to 4 AWG copper for distance and still keep the grounding conductor at 10 AWG copper because NEC 250.122 keys it to the overcurrent device.”
How to Use This With the Calculator
The calculator gives you a fast starting point, but serious installations still need one more pass for voltage drop, conductor temperature rating, and code-specific exceptions. That last review is where most inspection problems get removed before material is pulled.
elevator feeder wire sizing: Practical Number Checks
The easiest way to keep elevator feeder wire sizing practical is to sanity-check a few common field numbers before you order wire or close walls. On a 120V branch circuit carrying a 16A continuous load, the 125% rule pushes the conductor check to 20A. That is why 12 AWG copper becomes the real starting point instead of 14 AWG, even before you think about distance. If that same run stretches to 110 feet one way, voltage drop often pushes the design to 10 AWG while the breaker stays at 20A because the load has not changed.
The same logic shows up in larger work. A 7.5 HP, 460V three-phase motor with a full-load current around 11A does not mean you can stop at an 11A wire decision. Motor circuits, feeder calculations, and equipment grounding all apply their own code logic, and the conductor selected from ampacity tables still has to survive ambient temperature, rooftop heat, or bundling. That is why experienced electricians compare the load calculation against conductor ampacity, then against raceway or box space, and only then against the final breaker or fuse size.
Residential work needs the same discipline. A box-fill calculation that lands at 24.75 cubic inches on a 12 AWG two-gang box, or a detached garage feeder that picks up 3.6V of drop on a 120V leg, is already telling you the installation is too close to the edge. Use the long-distance wire guide when length is the problem, and cross-check enclosure constraints with the box fill guide or the conduit fill guide. Those second-pass checks are where most field rework gets avoided.
A good field habit is to compare at least two design options before material is ordered. For example, a 240V 32A EV charger on a 140-foot run may look acceptable on 8 AWG copper when you only review ampacity, but the same circuit may justify 6 AWG once you hold voltage drop close to a 3% design target. The same pattern shows up on pump circuits, detached-building feeders, and HVAC condensers. The circuit can be legal at one size and still perform better, start motors more reliably, and leave more inspection margin at the next size up.
elevator feeder wire sizing: Fast Field Comparison
The table below is not a substitute for the full article calculation, but it is a practical comparison lens for electricians, engineers, and serious DIY users who need a quick reasonableness check before they pull conductors. The numbers show how the design conversation changes once duration, distance, and enclosure limits are reviewed together instead of as isolated problems.
- Short branch circuits usually pass on ampacity alone, but continuous loads above 16A often force the next larger conductor or breaker check under the 125% rule.
- Runs around 100 to 150 feet are where voltage drop starts changing otherwise normal residential and light commercial conductor picks.
- Feeders and service work often pass ampacity first, then fail on grounding, raceway fill, or box-space details if those follow-up checks are skipped.
When those conditions stack together, the cheapest installation is rarely the smallest conductor that barely passes one table. The better choice is usually the conductor that clears ampacity, keeps voltage drop inside the design target, and still leaves room for a normal termination and inspection workflow.
elevator feeder wire sizing: Frequently Asked Questions
How do I know when elevator feeder wire sizing needs a larger conductor than a simple chart shows?
If the run is long, the load is continuous for 3 hours or more, or the conductors are bundled in hot ambient conditions, the simple chart is only the starting point. A 20A circuit may still need 10 AWG instead of 12 AWG once the 125% rule or a 3% voltage-drop target is applied.
Does the 125% continuous-load rule matter for elevator feeder wire sizing?
Yes, whenever the load is expected to run at maximum current for 3 hours or more. Under NEC 210.19(A)(1) and 215.2(A)(1), a 24A continuous load is treated as 30A for conductor sizing, which is why field calculations often move up one breaker and wire size from the first rough estimate.
What voltage-drop target is practical when planning elevator feeder wire sizing?
The common design target is about 3% on a branch circuit and 5% total for feeder plus branch circuit. That is not a mandatory blanket rule in every NEC application, but it is the benchmark many electricians use to decide when a 100-foot to 200-foot run should be upsized.
Can I upsize wire without increasing breaker size for elevator feeder wire sizing?
Yes. Upsizing for voltage drop or future durability does not automatically require a larger breaker. A common example is a 20A circuit that moves from 12 AWG to 10 AWG copper on a long run while the breaker remains 20A because the load and overcurrent protection have not changed.
Which code checks should I finish before calling elevator feeder wire sizing complete?
At minimum, verify conductor ampacity in NEC Table 310.16, breaker protection in NEC 240.4 and 240.6, voltage drop design assumptions, grounding in NEC 250.122, and enclosure or raceway space in NEC 314.16 or Chapter 9. For international work, align the same review with IEC-style conductor and protection practices.
When should I move from a chart lookup to a full calculation for elevator feeder wire sizing?
Move to a full calculation whenever the run exceeds roughly 75 to 100 feet, the load is motor-driven, the circuit is expected to operate for 3 hours or more, or the conductors share a hot raceway with more than three current-carrying conductors. Those are the situations where a simple chart is most likely to miss a required upsizing step.
What is the most common inspection failure tied to elevator feeder wire sizing?
The most common failures are not dramatic math mistakes. They are incomplete checks: a conductor that passes NEC Table 310.16 but ignores a 75 C termination, a long run that misses a 3% branch-circuit design review, or a feeder that works electrically but lands in an undersized box or raceway. Most red tags happen when one of those second-pass checks is skipped.
Next Steps
If you want to validate this topic against real project numbers, start with the wire gauge calculator, then cross-check longer runs in the voltage drop calculator, and verify conductor adjustments with the ampacity calculator. If you want us to add another worked example or application note, contact us here.