NEC 430.248 / 430.250 · Motor FLC explained

How to use the NEC motor full-load current tables

Table FLC vs. nameplate FLA, which voltage column to read, and how one number drives the wire, breaker, disconnect, and overload — with a worked 10 HP example.

Need the actual numbers?

This page teaches you how to use the NEC motor tables — it deliberately does not reproduce them. Look up Table 430.248 (single-phase) and Table 430.250 (three-phase) in the free NFPA 70 (NEC) online viewer (free NFPA account, read-only), or your printed code book (Article 430, Part XIV).

Section numbers and values vary by NEC edition, and your jurisdiction may adopt an older edition or local amendments. The edition your AHJ enforces governs.

Which table applies?

Motor	Where to look
DC motors	Table 430.247
Single-phase AC motors	Table 430.248
Two-phase AC motors (rare, legacy systems)	Table 430.249
Three-phase AC motors — induction (squirrel-cage and wound-rotor) and synchronous	Table 430.250 (synchronous motors have separate columns / notes on power factor)
Multispeed motors, shaded-pole and PSC fan motors, torque motors, AC adjustable-voltage motors	Exceptions to 430.6(A)(1) — these use nameplate current for some or all sizing. Read the exception.
Motor-operated appliances / hermetic refrigerant compressors	Appliance rules (Article 422) or Article 440 — branch-circuit selection current / rated-load current, not the motor tables.

How to read the motor tables, step by step

Step	What you do
1. Pick the right table	Match the motor type and phase to the table (see the decision table above).
2. Find the horsepower row	Rows are by nameplate horsepower. If the motor is rated in amps rather than HP, the table does not apply — use the nameplate and the relevant exception.
3. Pick the voltage column	Columns are motor voltages (slightly under system voltage). Use the column that corresponds to the system voltage range per the table heading — do not interpolate or scale by the voltage ratio.
4. Read the table notes	The notes explain which system voltages map to each column and that low-speed or high-torque motors can draw more than the table value — in which case the higher nameplate current is used.
5. Size from table FLC	Conductors (430.22: 125%), disconnect (430.110: 115%), and branch-circuit short-circuit/ground-fault protection (430.52 and its table of percentages by device type).
6. Size overloads from the nameplate	Overload protection uses nameplate FLA and the service factor / temperature-rise rules in 430.32 — not the table.
7. Multiple motors	Feeder conductors: 125% of the largest motor's FLC plus the sum of the others (430.24). Feeder protection follows 430.62.

Worked example: 10 HP, 480 V, three-phase

Step	Calculation
Inputs	10 HP, three-phase squirrel-cage induction motor on a 480 V system; nameplate FLA 13 A, service factor 1.15; inverse-time breaker; 75°C terminations.
Table FLC	Three-phase → Table 430.250, 10 HP row, 460 V column (the column for a 480 V system): 14 A.
Conductors (430.22)	14 A × 125% = 17.5 A minimum ampacity. Then pick the conductor from Table 310.16 in the termination column and check 240.4(D) / voltage drop.
Breaker (430.52)	Inverse-time breaker maximum is 250% of FLC: 14 × 2.5 = 35 A → 35 A is a standard size (240.6). Larger only under the 430.52 exceptions if the motor will not start.
Overload (430.32)	Uses nameplate, not table: service factor 1.15 permits up to 125% of nameplate FLA → 13 × 1.25 = 16.25 A max overload setting.
Disconnect (430.110)	At least 115% of table FLC: 14 × 1.15 = 16.1 A, and horsepower-rated for 10 HP at 480 V.

The table value is quoted only to illustrate the calculation. Look up your own motor in the official table for your adopted edition.

Common field mistakes

Mistake	What to do instead
Sizing the circuit from the nameplate FLA	Use table FLC for conductors, disconnects, and short-circuit protection; nameplate only for overloads.
Sizing overloads from the table	The overload protects this specific motor — it must follow the nameplate FLA and service factor.
Scaling current by voltage (e.g., 460 → 480)	Use the column the table heading assigns to your system voltage. The values already account for it.
Using the 230 V column on a 208 V system	Three-phase tables have a separate 208 V column; the current is higher. Single-phase has one too.
Treating 250% as a required breaker size	430.52 percentages are maximums. Smaller is fine if the motor starts reliably.
Forgetting the largest-motor 125% on feeders	Multiple-motor feeders use 125% of the largest FLC plus the others (430.24).
Using motor tables for A/C compressors	Hermetic refrigerant motor-compressors follow Article 440 and the equipment nameplate (MCA/MOCP).

What changed between editions

Edition	What to know
2017 / 2020 / 2023 NEC	The motor table numbers (430.247–430.250) and the core sizing rules (430.6, 430.22, 430.32, 430.52) have kept the same section numbers through recent editions. Surrounding text, exceptions, and some table notes are revised editorially from cycle to cycle.
2026 NEC and later	Being adopted state by state — confirm the table numbers, notes, and exceptions in the edition your AHJ enforces.

Orientation only — confirm in the edition your jurisdiction has adopted.

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When you need the motor FLC tables

Every motor branch circuit starts with the table full-load current (FLC). NEC 430.6(A)(1) sends you to Tables 430.247–430.250 by motor type, horsepower, and voltage — deliberately not to the nameplate, so the circuit still works when the motor is swapped for another brand of the same horsepower.

From that one number you size the conductors, disconnect, and short-circuit/ground-fault protection. The nameplate FLA comes back in only for the overload, which protects that specific motor from running hot.

The conductor itself comes from NEC Table 310.16; breaker sizes are standardized in 240.6. Check long feeder runs with the voltage drop calculator. Field PM keeps your equipment list, panel schedules, and commissioning records together on the job.

FAQ

Why use the NEC FLC table instead of the nameplate amps?+

NEC 430.6(A)(1) requires the table full-load current (Tables 430.247–430.250) for sizing conductors, disconnects, and short-circuit/ground-fault protection, so the circuit works for any replacement motor of the same horsepower. The nameplate full-load amps (FLA) are used for sizing the overload (running) protection under 430.32.

How do I size the wire for a motor?+

For a single continuous-duty motor, branch-circuit conductors must have an ampacity of at least 125% of the table FLC (430.22). Example: a 10 HP, 460 V, three-phase motor has a table FLC of 14 A (Table 430.250), so the conductors need at least 17.5 A of ampacity.

How do I size the breaker for a motor?+

Branch-circuit short-circuit and ground-fault protection is a percentage of table FLC that depends on the device type (Table 430.52). For an inverse-time breaker the maximum is 250%: for the 14 A example that is 35 A, which is a standard size. Exceptions allow going higher if the motor will not start.

Which voltage column do I use for a 480 V or 208 V system?+

The tables list motor voltages, which are slightly below system voltages. Use the column for the matching motor voltage (for example, the 460 V column for a 480 V system, the 230 V column for a 240 V system). Do not scale the current by the voltage ratio. 208 V systems have their own column.

Where can I see the motor FLC tables for free?+

NFPA publishes NFPA 70 (the NEC) in a free, read-only online viewer at nfpa.org/freeaccess. Open your adopted edition and go to Article 430, Part XIV (Tables).

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