13.1 Motor Nameplate Data & FLC Tables

Why FLC vs Nameplate Is the Motor Chapter Gate

The Arkansas Journeyman Electrician exam (Prov / ADLL, NEC 2023, 60 questions, 3 hours, 70% pass) weights Motors and Controls at 7 items. Nearly every motor stem starts with the same fork: which current do I use?

• Table full-load current (FLC) from Article 430 tables → conductors, short-circuit/ground-fault OCPDs, and disconnect ampere ratings
• Nameplate full-load amperes (FLA) → separate overload protection

If you reverse those currents, you can “do the math” perfectly and still miss the item. Tab 430.6, Tables 430.248 / 430.250, 430.22, 430.32, and Table 430.52 as one cluster before exam day. Controllers, control circuits, and disconnect location details continue in Chapter 14.

---

The Master Rule — 430.6(A)

430.6(A)(1) — Table values (not nameplate)

Except as required for overload protection, the motor current used for ampacity, short-circuit/ground-fault protection, and disconnect sizing is taken from the tables, not from the nameplate. Applicable tables:

On Prov, three-phase induction motors dominate. Open Table 430.250, find the hp row, then the voltage column that matches the stem (208 V, 230 V, 460 V, 575 V, etc.). Use that FLC for every calculation that 430.6(A)(1) covers.

430.6(A)(2) — Nameplate for overload

Separate motor overload protection is based on the motor nameplate current rating. That is the only place in the everyday motor-sizing workflow where nameplate FLA replaces Table FLC.

Exam mantra: Table for wire and breaker; nameplate for overload heater/setting.

---

What the Nameplate Still Tells You

Even when you refuse nameplate FLA for conductor sizing, you still need the nameplate for:

Trap: A stem that prints both “nameplate 12.4 A” and “10 hp, 460 V, 3-phase” is bait. For 430.22 conductor ampacity, open Table 430.250 (10 hp @ 460 V → 14 A), not 12.4 A. Save 12.4 A for the overload question in the next stem.

---

Reading Table 430.250 Cleanly

Workflow under time pressure:

1. Confirm three-phase AC (most commercial/industrial Arkansas stems).
2. Confirm synchronous speed / induction assumptions — the standard FLC tables are for the motors the section covers; unusual motors may have different rules (open 430.6 notes when the stem flags them).
3. Find hp.
4. Find voltage. Do not invent a midpoint between 230 V and 460 V columns.
5. Record FLC and write it on scratch paper before multiplying by 125% or Table 430.52 percentages.

Worked FLC lookups (verify in your NEC)

These values are the ones Prov-style items reuse constantly — always confirm in Table 430.250:

Single-phase shop motors use Table 430.248. Example pattern: a 3 hp, 230 V, 1φ motor uses the single-phase table FLC (commonly 17 A — verify), not the three-phase 9.6 A row.

Voltage trap: A motor labeled 208 V is not automatically the 230 V column. Use the column that matches the stem. If only 230 V and 460 V appear and the stem says 208 V, open the table notes/columns carefully — do not casually “borrow” 230 V without checking.

---

Why the Code Prefers Tables Over Nameplates

The FLC tables are intentional conservatism for replacement motors. A future motor of the same hp and voltage might draw more nameplate current than today’s efficient unit. Conductors and SC/GF devices sized from today’s low nameplate could be inadequate for the next motor. Overload devices, by contrast, must protect this motor’s windings — so they follow this nameplate.

That policy explanation is useful when two answers both look “numerically right.” Ask: am I protecting the circuit/conductors against faults, or the motor against running overload?

---

Multi-Speed, Dual-Voltage, and Special Motors

Prov will occasionally spice a stem:

• Dual-voltage motors: Size from the voltage at which the motor is connected. A dual-voltage 230/460 V motor connected for 460 V uses the 460 V FLC column.
• Multi-speed motors: Follow the Part / section rules for the winding in use; do not average currents.
• Design B vs other designs: Starting current and Code letter affect some protective-device exception paths later; they do not let you skip Table FLC for ordinary continuous-duty conductor sizing.

If the stem says “hermetic refrigerant motor-compressor,” you may be pushed toward Article 440, not Article 430’s general motor tables. Identity first, article second.

---

Connecting FLC to the Rest of Article 430 Parts

Keep the Part map in your head so lookups stay short:

This section owns the current-selection skill. Sections 13.2–13.4 apply the multipliers.

---

Timed Open-Book Tips for §13.1

• First underline: nameplate vs table / FLC / FLA in the stem.
• Open 430.6 only long enough to confirm which current — then jump to the table.
• Write FLC on scratch paper before any 125% or 250% math.
• Never use nameplate FLA for 430.22 or Table 430.52 unless a specific exception in the Code says so for that equipment type.
• If both currents are printed, Prov is almost certainly testing whether you know 430.6(A)(1) vs (A)(2).