Commercial Laundry Equipment Wire Sizing Guide
// SIZE WASHER EXTRACTORS, TUMBLE DRYERS, IRONERS, BOILER FEEDS, AND LAUNDROMAT PANELS WITH NEC AMPACITY, MOTOR, CONTINUOUS-LOAD, VOLTAGE-DROP, AND IEC CHECKS. //
Commercial laundry wiring looks simple only when every machine is reduced to one amp number. Real laundromats and hotel laundry rooms combine resistance heat, motors, controls, payment equipment, booster heaters, ventilation, pumps, and sometimes small boilers. A 60 A dryer, a 30 A washer extractor, and a 125 A flatwork ironer are not the same design problem. The branch-circuit conductor may be controlled by terminal temperature, continuous-load duty, motor starting, voltage drop, or the manufacturer maximum overcurrent device. A calculator is useful, but it has to be fed the right load type.
Start with each equipment nameplate, not a generic dryer or motor chart.
Check NEC 110.14(C), 210.19(A), 215.2(A), 310.16, 422, 430, and voltage drop separately.
Long 208 V laundry runs often need upsizing even when ampacity already passes.
Treat heated dryers, ironers, boosters, and boiler loads differently from washer motors and controls.
Example 1: 208 V electric dryer, 48 A nameplate, 145 ft run
Start with the nameplate: 48 A at 208 V single-phase. If the manufacturer allows a 60 A circuit and 75C copper terminals, 6 AWG copper is a common ampacity screen from NEC 310.16. Now check voltage drop. At 48 A and 145 ft, the drop may exceed a 3 percent branch-circuit target, depending on conductor resistance and raceway temperature. Upsizing to 4 AWG copper lowers resistance and improves dryer heat-up. The breaker still follows the manufacturer MOCP, the conductor upsize does not authorize a larger breaker.
TL;DR
- Start with each equipment nameplate, not a generic dryer or motor chart.
- Check NEC 110.14(C), 210.19(A), 215.2(A), 310.16, 422, 430, and voltage drop separately.
- Long 208 V laundry runs often need upsizing even when ampacity already passes.
- Treat heated dryers, ironers, boosters, and boiler loads differently from washer motors and controls.
- For IEC projects, use IEC 60364-5-52 cable capacity and IEC 60364-4-43 overcurrent coordination.
Definitions That Keep The Laundry Calculation Honest
MCA
Minimum circuit ampacity is the manufacturer or code-derived ampere value used to size branch-circuit conductors before voltage-drop upsizing.
MOCP
Maximum overcurrent protection is the largest breaker or fuse the equipment instructions allow for short-circuit and ground-fault protection.
Continuous load
A continuous load is a load expected to run at maximum current for 3 hours or more, many laundry rooms have long operating cycles, but the classification must match the actual load and instructions.
A Practical Wire-Sizing Workflow For Laundry Equipment
1
Record each nameplate value: voltage, phase, MCA, MOCP, heater kW, motor FLA, control voltage, required conductor material, and environmental limits.
2
Resistance dryers and ironers are heat loads, washer extractors are motor-plus-control machines, booster heaters and boilers may be continuous support loads.
3
Apply ambient correction and conductor-count adjustment before accepting the size.
4
A washer extractor motor may need conductors sized for motor FLA while the machine listing controls the final branch-circuit rating.
Worked Examples With Specific Numbers
Example 1: 208 V electric dryer, 48 A nameplate, 145 ft run
Use these examples as calculation patterns. Always replace the example current with the actual machine nameplate and local code edition.
Start with the nameplate: 48 A at 208 V single-phase. If the manufacturer allows a 60 A circuit and 75C copper terminals, 6 AWG copper is a common ampacity screen from NEC 310.16. Now check voltage drop. At 48 A and 145 ft, the drop may exceed a 3 percent branch-circuit target, depending on conductor resistance and raceway temperature. Upsizing to 4 AWG copper lowers resistance and improves dryer heat-up. The breaker still follows the manufacturer MOCP, the conductor upsize does not authorize a larger breaker.
Example 2: 480 V three-phase washer extractor, 27 A MCA, VFD input
Use these examples as calculation patterns. Always replace the example current with the actual machine nameplate and local code edition.
A washer extractor nameplate lists 480 V, 3-phase, 27 A minimum circuit ampacity, and 40 A maximum overcurrent protection. Start with 10 AWG copper if terminal and derating conditions allow the ampacity, then verify the VFD input current and manufacturer instructions. If six similar circuits share one raceway, conductor-count adjustment may force an upsize. The equipment grounding conductor is sized from the overcurrent device, not from the VFD marketing horsepower.
Example 3: 125 A ironer feeder with 120 A continuous heat load
Use these examples as calculation patterns. Always replace the example current with the actual machine nameplate and local code edition.
A flatwork ironer draws 120 A of electric heat for long operating blocks and has small drive motors. If the load is treated as continuous, the conductor sizing basis can become 120 A x 125 percent = 150 A before selecting conductor ampacity, unless the equipment listing gives a different MCA. At 75C, that can push the design into 1/0 copper territory before voltage drop. The overcurrent device must still coordinate with the equipment instructions.
Common Commercial Laundry Loads Compared
| Equipment | Typical electrical load | Main code check | Starting conductor screen | Field check before install |
|---|---|---|---|---|
| 60 lb gas tumble dryer;120 V or 208-240 V controls plus motor, 8-18 A common;NEC 422 and 430;14-10 AWG copper depending on nameplate;Verify ignition/control load, disconnect, and receptacle/listing details. | Electric tumble dryer;208 V or 240 V heat, often 40-80 A per pocket;NEC 422, 210.19(A), 310.16;8-4 AWG copper by MCA and distance;Check continuous duty, terminal temperature, and voltage drop above 100 ft. | Washer extractor;3-phase motor, drive, valves, controls, 15-40 A common;NEC 430 plus listing instructions;12-8 AWG copper by MCA/MOCP;Confirm VFD input current, imbalance, and short-circuit rating. | Flatwork ironer;Large resistance heat plus motors, 60-150 A common;NEC 422, feeder rules;6-1/0 AWG copper by nameplate;Treat heat duty seriously and check feeder capacity during peak operation. | Booster heater or small boiler feed;Electric heat or pump/control load, 30-125 A common;NEC 422, 424, 430 as applicable;10-1 AWG copper by MCA;Check whether the support load runs continuously during wash cycles. |
Primary Code And Reference Points
This guide uses NEC 110.14(C), NEC 210.19(A)(1), NEC 215.2(A)(1), NEC 220, NEC 310.16, NEC Article 422, NEC Article 430, and IEC 60364-5-52 as design anchors. The National Electrical Code is the US installation code, IEC 60364 is an international low-voltage installation standard series, and three-phase electric power is the usual supply method for larger commercial washers, dryers, ironers, and boiler rooms.
NEC 422
This guide uses NEC 110.14(C), NEC 210.19(A)(1), NEC 215.2(A)(1), NEC 220, NEC 310.16, NEC Article 422, NEC Article 430, and IEC 60364-5-52 as design anchors. The National Electrical Code is the US installation code, IEC 60364 is an international low-voltage installation standard series, and three-phase electric power is the usual supply method for larger commercial washers, dryers, ironers, and boiler rooms.
NEC 430
Size washer extractors, tumble dryers, ironers, boiler feeds, and laundromat panels with NEC ampacity, motor, continuous-load, voltage-drop, and IEC checks.
NEC 210, 215, 220, 310
Size washer extractors, tumble dryers, ironers, boiler feeds, and laundromat panels with NEC ampacity, motor, continuous-load, voltage-drop, and IEC checks.
IEC 60364 / IEC 60228
For IEC projects, use IEC 60364-5-52 cable capacity and IEC 60364-4-43 overcurrent coordination.
Field Scenario: Why The Panel Schedule Was Not Enough
- A contractor asked for a quick review of a 208Y/120 V laundromat service before rough-in. The room had six electric dryers at 48 A nameplate, four washer extractors at 22 A, a 36 A booster heater, and a small 120 V control/payment load. The first panel schedule treated every dryer as a simple 50 A branch circuit and placed the farthest machines 155 ft from the panel. Ampacity alone pointed to 6 AWG copper for several circuits, but voltage drop at 48 A over that distance was outside the owner target.,The fix was to move the distribution panel closer to the dryer wall, upsize the two unavoidable long dryer circuits to 4 AWG copper, and keep washer/VFD circuits in a separate raceway from the largest heater circuits. The feeder calculation also changed: the design team documented which machines could realistically run together during the Saturday peak instead of assuming a residential-style laundry demand. The result was a cleaner inspection package and fewer voltage-related nuisance complaints at commissioning.,This scenario is not a fabricated testimonial; it is the kind of review pattern that repeats in small commercial laundry projects. The lesson is concrete: when a 208 V heat load is both high-current and far from the panel, voltage drop can become the controlling decision after NEC ampacity already passes.
- Copying a residential dryer wire-size rule into a multi-machine commercial room.
- Ignoring manufacturer MCA and MOCP values because a generic chart seems close.
- Using the 90C insulation ampacity as the final answer when equipment lugs are limited by NEC 110.14(C).
- Forgetting conductor-count adjustment when many dryer circuits share a raceway.
- Treating voltage drop as optional on long 208 V heat loads.
FAQ: Commercial Laundry Equipment Wire Sizing
What wire size is typical for a 60 A commercial dryer circuit?
A 60 A circuit often starts with 6 AWG copper when 75C terminals are available, but the final answer depends on NEC 310.16, NEC 110.14(C), conductor count, ambient temperature, and voltage drop. A 120-150 ft run can justify 4 AWG copper even when the breaker remains 60 A.
Are washer extractors sized as motors or appliances?
Use the listed nameplate first. Many washer extractors combine motors, VFDs, valves, controls, and heaters, so the branch circuit may be governed by manufacturer MCA/MOCP while NEC Article 430 still informs motor and drive checks. A 27 A MCA and 40 A MOCP should not be replaced by a generic horsepower table.
How should I handle voltage drop in a laundromat?
Run voltage drop after ampacity. Many designers use the NEC informational-note target of about 3 percent branch circuit and 5 percent total feeder plus branch circuit. On 208 V equipment, a 6 V drop is already about 2.9 percent, so long dryer runs deserve attention.
Can multiple commercial dryers share one feeder?
Yes, if the feeder, panel, overcurrent protection, neutral, grounding, and demand calculation are designed for the actual simultaneous load. Six 48 A dryers can represent 288 A of connected dryer load before demand or operational diversity is justified.
Does IEC use the same AWG sizes for laundry equipment?
No. IEC projects normally use metric conductors such as 6 mm2, 10 mm2, 16 mm2, 25 mm2, or 35 mm2. Start with IEC 60364-5-52 current-carrying capacity, installation method, grouping, ambient temperature, and voltage-drop limits, then coordinate protection under IEC 60364-4-43.
When should I upsize beyond the nameplate minimum?
Upsize when voltage drop, ambient correction, conductor-count derating, terminal limits, or future equipment replacement requires it. For example, a 48 A dryer 145 ft away may need 4 AWG copper for voltage performance even though 6 AWG passed the initial ampacity screen.
Need A Second Check On A Laundry Panel?
Use the calculators to screen branch circuits, feeders, and voltage drop, then contact us when the laundry room has long runs, dense raceways, mixed voltages, or high-duty equipment.