2023 NEC Article 430 Motor Control Georgia PSI Exam

# 2023 NEC Article 430 Motor Control Requirements: What Georgia Inspectors Enforce on the PSI Exam

When I sat down to prep for my Georgia electrical contractor license, NEC Article 430 motor control requirements was one section I couldn't skip. Every inspector I've worked with knows this article cold, and the PSI exam reflects that. Let me walk you through what actually matters for your Class I or Class II exam.

Key facts

The motor disconnecting means must be rated at least 115% of the motor's full-load current and listed for the motor's horsepower, per NEC 430.109–430.113.
The disconnect and the controller must each be within sight of the motor, meaning within 50 feet and in direct visible line of sight, per NEC 430.107.
NEC 430.52 sets branch circuit protection maximums as a percentage of full-load current: 300% for non-time-delay fuses, 175% for dual-element (time-delay) fuses, 700% for instantaneous trip breakers, and 250% for inverse-time (standard) breakers.
A continuous-duty motor's overload protection must be set at no more than 125% of full-load current for motors with a service factor of 1.15 or greater, or 115% for motors with lower service factors, per NEC 430.32(A).
Intermittent-duty and short-time duty motors may have overload protection set at no more than 140% of full-load current, per NEC 430.32(D).
Full-load current tables are found at Table 430.248 for single-phase AC motors, Table 430.249 for two-phase AC motors, Table 430.250 for three-phase AC motors, and Table 430.251 for direct current motors.

Why Article 430 Matters for Your Georgia PSI Exam

Article 430 isn't abstract code—it's how we keep motors from burning down buildings and how we protect people working on motor circuits. That's why Georgia's PSI exam tests it heavily.

The section covers:

Motor disconnecting means (size and location)
Motor branch circuit protection
Motor overload protection
Motor controllers
Motor feeder protection

If you're testing for Class II (unrestricted), you need solid understanding of all five areas. Class I (restricted) typically focuses on smaller systems, but the fundamental rules stay the same.

The 2023 NEC Changes to Article 430

Let me be straight with you: the 2023 code introduced specific updates that the PSI outline now tests. These aren't theoretical—Georgia inspectors are actively looking for compliance.

Motor Nameplate and Controller Requirements (2023 Update)

In the 2023 NEC, Section 430.7 received clarification on nameplate marking requirements. Motors must now be clearly marked with:

Voltage rating
Amperage rating
Frequency
Duty cycle
Power factor (where applicable)
Code letter marking (for locked-rotor current)

Why does this hit the exam? Because you must interpret that nameplate to size disconnects and overcurrent devices. If you misread a nameplate, your entire circuit design fails. PSI questions often present a scenario with a motor nameplate and ask you to select the correct disconnect or protection device.

Controller Requirements Under 2023 Updates

NEC 430.81 and 430.82 were refined in 2023 to clarify controller construction and marking. A motor controller must:

Carry a voltage and current rating suitable for the circuit
Be marked with its current rating (if it's a component of a larger device)
Be suitable for the duty cycle and environmental conditions

On the exam, you might see: "A single-phase motor controller in a damp location must meet which requirement?" The answer hinges on understanding that controllers must be listed for their environment per 430.83.

Motor Disconnecting Means: What Georgia Inspectors Always Check

This is where I see the most exam questions, and honestly, the most field failures.

Size and Type of Disconnect (NEC 430.109 – 430.113)

The disconnecting means must be rated in horsepower. That's critical. You don't size it by amperage alone.

Here's the rule: The disconnect must be rated at least 115% of the motor's full-load current (in amperes) and be listed for the horsepower of the motor.

Let me give you a concrete example:

You have a 3 HP, 208V, 3-phase motor
Full-load current per Table 430.250: 8.4 amps
Minimum disconnect amperage: 8.4 × 1.15 = 9.66 amps
But you still need a 3 HP-rated disconnect (not just a 10-amp switch)

That's a PSI favorite question format: "Can you use a 15-amp rated switch as the disconnect for a 3 HP motor?" Answer: No, because it's not horsepower-rated, even though the amperage math works.

Location of Disconnect (NEC 430.107)

The disconnect must be:

Within sight of the motor (within 50 feet and visible line of sight per NEC Article 100)
Within sight of the controller (same 50-foot, visible rule)
Accessible to the operator

Georgia inspectors fail installations when the disconnect is:

Behind a locked cabinet the operator doesn't have keys for
Located more than 50 feet away (out of sight around a corner)
Blocked by stored equipment

The exam will ask: "Where must the motor disconnect be located?" Know the three criteria cold.

Motor Branch Circuit Protection (NEC 430.52)

This is different from overload protection—it's short-circuit and ground-fault protection.

Branch Circuit Short-Circuit and Ground-Fault Protection (NEC 430.52)

The branch circuit overcurrent device protects the wiring and motor against shorts. It's sized based on the motor's full-load current and the type of protective device.

| Device Type | Maximum % of FLC | |---|---| | Non-time-delay fuse | 300% | | Dual-element (time-delay) fuse | 175% | | Instantaneous trip breaker | 700% | | Inverse-time (standard) breaker | 250% |

Here's where it gets real: You're installing a 10 HP, 3-phase, 480V motor. Full-load current is 12.5 amps (per Table 430.250).

Using a dual-element fuse:

Maximum size = 12.5 × 1.75 = 21.875 amps
You'd select a 20-amp dual-element fuse

Using an instantaneous breaker:

Maximum size = 12.5 × 7.0 = 87.5 amps
You could go up to an 80-amp breaker (next standard size below)

The PSI exam will test whether you pick the right percentage for the device type. That table is exam gold—memorize it.

Exception for Starting Currents (NEC 430.52(C))

If the motor won't start with standard branch circuit protection, you may increase to the next higher standard size. But there's a catch: you can't exceed the percentages above, and NEC 430.52(C)(1) Exception No. 2 limits this—you have to ensure it still protects the circuit adequately.

Georgia inspectors watch for installers who bump up protection too far and call it a "starting issue." The code is specific, and the exam tests this boundary.

Motor Overload Protection (NEC 430.32)

Don't confuse this with branch circuit protection. Overload protection guards the motor itself against sustained overcurrent (not short-circuits).

Continuous-Duty Motors (NEC 430.32(A))

A continuous-duty motor must have overload protection rated or set at no more than 125% of the motor's full-load current (for motors with a service factor of 1.15 or greater) or 115% (for motors with lower service factors).

Overload devices include:

Thermal overload relays
Electronic overload relays
Motor protection circuit breakers

Here's an exam scenario: "A 5 HP, single-phase motor has a nameplate FLC of 28 amps. The overload setting must not exceed ___?"

Answer: 28 × 1.25 = 35 amps (assuming standard service factor).

Why does this matter to Georgia inspectors? Because undersized overload protection lets motors fail prematurely and overheat winding insulation. Oversized protection lets them burn up.

Intermittent-Duty Motors (NEC 430.32(D))

Intermittent-duty and short-time motors have different rules. For short-time duty motors, overload protection may be set at no more than 140% of FLC. The exam will test whether you know when to apply this exception.

Motor Controllers (NEC 430.81 – 430.91)

A motor controller is any device that starts, stops, or regulates a motor. It could be:

A manual starter
A magnetic contactor
A variable frequency drive (VFD)
A soft starter

What Must Be Marked on a Controller (2023 NEC 430.8 Series)

Under 2023 updates, controllers must be marked with:

Voltage rating (suitable for the circuit)
Current rating (if not plainly visible on the device)
Duty cycle (continuous, intermittent, etc.)

The exam tests your ability to verify a controller is suitable before installation. A question might ask: "Can a controller marked 'single-phase, 120V' be used on a three-phase, 208V circuit?" Answer: Absolutely not.

Motor Controller in Sight of Motor (NEC 430.107(A))

The controller must also be within sight of the motor—same 50-foot, visible-line-of-sight rule. This is often tested alongside disconnect requirements.

Practical Exam Tips for Article 430

Tip 1: Use the Full-Load Current Tables (NEC Table 430.248 – 430.251)

Every exam I've seen includes at least one question requiring you to reference FLC tables. Know where they are:

Table 430.248: Single-phase, AC motors (115V, 230V)
Table 430.249: Two-phase, AC motors
Table 430.250: Three-phase, AC motors
Table 430.251: Direct current motors

On test day, you'll have the NEC in front of you. Use it. Don't memorize FLC values—reference the tables.

Tip 2: Distinguish Between Protection Types

The exam will mix:

Branch circuit protection (short-circuit/ground-fault)
Overload protection (motor thermal protection)
Disconnecting means (horsepower-rated, within sight)

Know the purpose and sizing rules for each. They're tested separately.

Tip 3: Test Scenarios Often Include Nameplate Data

Expect a question like: "A three-phase motor is marked: 10 HP, 230V, 28 FLC, Service Factor 1.15. What is the maximum overload setting?"

Answer: 28 × 1.25 = 35 amps.

You'll need to pull the nameplate information and apply Article 430 rules. Practice this format repeatedly.

Tip 4: Know the 50-Foot Rule for Disconnect and Controller Location

Georgia inspectors enforce NEC 100's definition of "in sight from":

Within 50 feet
Directly visible (not obscured or around corners)

It's a gate question on the exam. If the scenario says the disconnect is 60 feet away but visible, it fails. If it's 40 feet away but behind a wall, it fails.

2023 NEC Article 430 Topics Likely on Your PSI Exam

Based on how PSI outlines exams for Georgia, here's what you should study most:

Motor branch circuit protection sizing (430.52) — Very high likelihood
Motor disconnecting means ratings and location (430.107–430.113) — Very high likelihood
Motor overload protection settings (430.32) — High likelihood
Motor controller suitability (430.81–430.83) — Medium-high likelihood
Nameplate interpretation (430.6–430.8) — Medium-high likelihood
Feeder protection for motors (430.62) — Medium likelihood

Wrapping Up: Your Study Strategy

Article 430 is dense, but it's also repeatable. Here's my approach:

Read 430.1 and 430.2 to understand scope and purpose
Work through a motor circuit scenario end-to-end: nameplate → disconnect size → branch circuit protection → overload → controller
Drill the tables (FLC, protection percentages)
Practice nameplate scenarios from your Georgia electrical license practice test materials
Review the 2023 changes specifically around controller marking and motor nameplate requirements

When you're taking the PSI exam and you hit an Article 430 question, slow down. Identify whether it's asking about protection, disconnecting means, or controllers. Reference the appropriate section. Use the tables. You've got this.

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Ready to test your Article 430 knowledge? Work through sample questions in our Georgia electrical license practice test or review our guide on 2023 NEC changes Georgia electricians need to know.

Common questions

Can a 15-amp rated switch be used as the disconnect for a 3 HP motor?

No. Even if the amperage math works out, the disconnecting means must be rated in horsepower, not just amperage, per NEC 430.109–430.113. A 3 HP motor requires a disconnect listed for that horsepower rating, not merely a switch with a sufficient amp rating.

How far away can a motor disconnect or controller be located from the motor?

The disconnect and the controller must both be within sight of the motor, which NEC 100's definition of "in sight from" sets at within 50 feet and in a direct, unobstructed line of sight, as applied under NEC 430.107. A disconnect 60 feet away but visible fails this rule, and so does one 40 feet away but hidden behind a wall.

What's the difference between branch circuit protection and overload protection for motors?

Branch circuit protection, covered under NEC 430.52, protects the wiring and motor against short circuits and ground faults, and is sized using percentages of full-load current that vary by device type (for example, 175% for a dual-element fuse or 700% for an instantaneous trip breaker). Overload protection, covered under NEC 430.32, instead guards the motor itself against sustained overcurrent, with continuous-duty motors limited to 125% of FLC (or 115% for lower service factor motors). The two protections serve different purposes and are tested separately on the exam.

How do I calculate the maximum overload setting for a motor?

Take the motor's full-load current from the nameplate or the appropriate FLC table and multiply by 125% for a motor with a service factor of 1.15 or greater, per NEC 430.32(A). For example, a motor with a nameplate FLC of 28 amps and a standard service factor would have a maximum overload setting of 28 × 1.25 = 35 amps.

What must be marked on a motor controller under the 2023 NEC?

Under the 2023 NEC 430.8 series, controllers must be marked with a voltage rating suitable for the circuit, a current rating if it is not plainly visible on the device, and the duty cycle, such as continuous or intermittent. Controllers must also be listed for their environment per 430.83, and NEC 430.81 and 430.82 clarify controller construction and marking requirements.