What is NEC Table 430.250?

NEC Table 430.250 lists the Full Load Current (FLC) for three-phase alternating-current motors at common system voltages (115V, 200V, 208V, 230V, 460V, 575V, 2300V, 4000V). The table is used for branch circuit conductor sizing (per 430.22) and short-circuit / ground-fault protection sizing (per 430.52). It is NOT used for overload protection — that uses the motor nameplate FLA per 430.32.

What's the difference between FLC and FLA?

FLC (Full Load Current) is from NEC Tables 430.247-250. It is a standardized value based on motor horsepower and voltage. Used for branch circuit conductor sizing (430.22) and SCGF protection (430.52). FLA (Full Load Amps) is from the motor nameplate. It reflects the specific motor's tested current draw. Used for overload protection (430.32) and motor controller sizing. Mixing them up is the single most common motor-question trap on electrician exams.

Why does NEC use FLC from a table instead of nameplate FLA?

Because branch circuit conductors and SCGF protection devices are sized for the worst-case motor of that horsepower, not for one specific motor. A 25 HP, 460V motor from manufacturer A might pull 33 amps; from manufacturer B, 35 amps. Using the table FLC (34 A) gives a consistent reference for sizing infrastructure that doesn't change when you swap motors of the same HP. Nameplate FLA varies; table FLC doesn't.

What is 430.22 conductor sizing?

NEC 430.22(A) requires branch circuit conductors for a single continuous-duty motor to have an ampacity of at least 125% of the motor's FLC from Table 430.247-250. The 125% accounts for typical motor inrush during normal operation and motor heating from continuous load. Example: 25 HP, 460V, 3-phase motor has 34 A FLC. Conductor ampacity ≥ 34 × 1.25 = 42.5 A. Pick conductor size from Table 310.16 with that ampacity at the applicable temperature column.

How do I size short-circuit / ground-fault protection per 430.52?

Table 430.52 gives the maximum percentage of FLC for the SCGF device. Common values for a three-phase squirrel-cage motor with no Code letter or Code letters B-E: inverse-time circuit breaker = 250% of FLC, time-delay (dual-element) fuse = 175% of FLC, non-time-delay fuse = 300% of FLC. Higher percentages allow the motor's normal inrush current without nuisance tripping while still providing fault protection.

Are the Table 430.250 values exactly what the motor draws?

No. Table 430.250 values are conservative estimates that envelope the worst-case current for typical motors of that HP and voltage. Real motors usually draw less. The table is a sizing reference, not a measurement. For overload protection — which IS sized to the actual motor's current draw — you use the nameplate FLA per 430.32, not the table FLC.

Article 430 · NEC Table 430.250 deep-dive

NEC Table 430.250: Three-Phase Motor FLC for Branch Circuit Sizing

Article 430 motor questions are 8-12% of every TDLR Journeyman and California General Electrician exam. Table 430.250 is the table that drives most of them. The single most common motor-question trap: mixing Table 430.250 FLC with motor nameplate FLA. Here's the table, the rule that uses it, and the trap to avoid.

Last reviewed May 2026

FLC vs FLA — the distinction that decides most motor questions

FLC (Full Load Current): from NEC Tables 430.247 (DC), 430.248 (single-phase AC), 430.249 (two-phase), or 430.250 (three-phase). Used for: branch circuit conductor sizing (430.22) and short-circuit/ground-fault protection (430.52).
FLA (Full Load Amps): from the motor nameplate. Used for: overload protection (430.32) and motor controller sizing.

NEC Table 430.250 values (three-phase motors)

The most common voltages on the exam are 230V (residential and light commercial three-phase), 460V (commercial and industrial), and 575V (some industrial). The table also covers 200V, 208V, 2300V, 4000V — verify the column you need on the exam.

HP	230V FLC	460V FLC	575V FLC
1/2	2.2 A	1.1 A	0.9 A
3/4	3.2 A	1.6 A	1.3 A
1	4.2 A	2.1 A	1.7 A
1-1/2	6.0 A	3.0 A	2.4 A
2	6.8 A	3.4 A	2.7 A
3	9.6 A	4.8 A	3.9 A
5	15.2 A	7.6 A	6.1 A
7-1/2	22 A	11 A	9 A
10	28 A	14 A	11 A
15	42 A	21 A	17 A
20	54 A	27 A	22 A
25	68 A	34 A	27 A
30	80 A	40 A	32 A
40	104 A	52 A	41 A
50	130 A	65 A	52 A
60	154 A	77 A	62 A
75	192 A	96 A	77 A
100	248 A	124 A	99 A
125	312 A	156 A	125 A
150	360 A	180 A	144 A
200	480 A	240 A	192 A

Memorize the 460V column for the most common commercial motors (10 HP through 50 HP). Most exam questions will reference 460V three-phase motors in this HP range.

NEC 430.22 — Branch circuit conductor sizing

For a single continuous-duty motor, branch circuit conductors must have an ampacity of at least 125% of the FLC from Table 430.247-250.

Formula: Required conductor ampacity ≥ FLC × 1.25

Worked example: 25 HP, 460V three-phase motor

Look up FLC: Table 430.250, 25 HP, 460V column → 34 A
Apply 125%: 34 × 1.25 = 42.5 A
Required conductor ampacity: at least 42.5 A
Look up conductor size in Table 310.16 (75°C column for typical equipment): 6 AWG copper = 65 A, 8 AWG copper = 50 A
Smallest conductor with ≥ 42.5 A ampacity at 75°C: 8 AWG copper
Final answer: 8 AWG copper minimum

NEC Table 430.52 — Short-circuit / ground-fault protection

Per 430.52, the OCPD protecting the motor branch circuit (as protection against short circuits and ground faults, NOT against overload) is sized as a percentage of FLC. Table 430.52 gives the maximum percentages, varying by motor type and protection device.

For a typical three-phase squirrel-cage motor with Code letters B-E or no Code letter:

Inverse-time circuit breaker: 250% of FLC
Non-time-delay (instantaneous-trip-only) fuse: 300% of FLC
Time-delay (dual-element) fuse: 175% of FLC
Instantaneous-trip breaker: 800% of FLC (with engineering supervision)

Worked example: SCGF for 25 HP, 460V motor with inverse-time breaker

FLC: 34 A (Table 430.250)
Apply 250% per Table 430.52: 34 × 2.5 = 85 A
Standard breaker sizes per 240.6(A): 80 A, 90 A, 100 A...
Per 430.52(C)(1) Exception 1, next standard size up is permitted if 250% doesn't equal a standard rating
Final answer: 90 A inverse-time circuit breaker

How motor sizing questions appear on the exam

Question type 1: Direct conductor sizing (430.22)

“A continuous-duty 30 HP, 460V three-phase squirrel-cage motor. What is the minimum branch circuit conductor ampacity?” Answer: 40 A FLC × 1.25 = 50 A required ampacity.

Question type 2: SCGF sizing (430.52)

“Same motor with time-delay fuse protection. What is the maximum fuse size?” Answer: 40 A FLC × 1.75 = 70 A. Standard fuse size 70 A.

Question type 3: FLC vs FLA discrimination

“A 25 HP, 460V motor has nameplate FLA of 31 A. What is the minimum branch circuit conductor ampacity per 430.22?” Trap: candidates use 31 A nameplate. Correct answer uses Table 430.250 FLC of 34 A. Result: 34 × 1.25 = 42.5 A, NOT 31 × 1.25 = 38.75 A.

Question type 4: Overload (430.32) — uses nameplate, NOT FLC

“Same motor with nameplate FLA of 31 A and service factor 1.15. What is the maximum overload setting per 430.32(A)(1)?” Answer: 31 × 1.25 = 38.75 A. THIS time we use the nameplate FLA, not the table FLC. Same motor, two different numbers, two different sizing decisions.

Common 430.250 mistakes

Using nameplate FLA when 430.22 calls for FLC from Table 430.250
Reading the 230V column for a 460V motor (or vice versa) — common copy-paste error on multi-part questions
Forgetting that 430.22 requires 125% of FLC, not 100%
Using inverse-time breaker percentages (250%) when the question specifies time-delay fuse (175%)
Forgetting the “next standard size up” allowance per 430.52(C)(1) Exception 1 when the calculated value doesn’t match a standard rating
Mixing single-phase Table 430.248 with three-phase Table 430.250 — different tables for different motor types

Drill motor sizing across all four sizing decisions

The diagnostic includes motor problems for branch circuit, overload, SCGF, and feeder. Many candidates get one right and miss the other three because they mix FLC with FLA.

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