sufficient time delay to permit the motor to start and accelerate its load.

430.43 Automatic Restarting. A motor overload device that can restart a motor automatically after overload tripping shall not be installed unless approved for use with the motor it protects. A motor overload device that can restart a motor automatically after overload tripping shall not be installed if automatic restarting of the motor can result in injury to persons.

430.44 Orderly Shutdown. If immediate automatic shutdown of a motor by a motor overload protective device(s) would introduce additional or increased hazard(s) to a person^) and continued motor operation is necessary for safe shutdown of equipment or process, a motor overload sensing device(s) complying

Exception No. 1: Where the values for branch-circuit short-circuit and ground-fault protective devices deter- mined by Table 430.52 do not correspond to the standard sizes or ratings of fuses, nonadjustable circuit breakers, thermal protective devices, or possible settings of adjustable circuit breakers, a higher size, rating, or possible setting that does not exceed the next higher standard ampere rating shall be permitted.

Exception No. 2: Where the rating specified in Table

430.52, or the rating modified by Exception No. 1, is not

sufficient for the starting current of the motor:

(a) The rating of a nontime-delay fuse not exceeding

600 amperes or a time-delay Class CC fuse shall be per-

Table 430.52 Maximum Rating or Setting of Motor Branch- Circuit Short-Circuit and Ground-Fault Protective Devices

Percentage of Full-Load Current

with the provisions of Part III of this article shall be permitted to be connected to a supervised alarm instead of causing immediate interruption of the motor

Type of Motor Nontim e Delay Fuse 1

Dual Element

(Time-Delay)

Instantaneous

Trip

Inverse

Time

circuit, so that corrective action or an orderly shutdown
can be initiated.

IV. Motor Branch-Circuit Short-Circuit and

Ground-Fault Protection

430.51 General. Part IV specifies devices intended to protect the motor branch-circuit conductors, the motor control apparatus, and the motors against overcurrent due to short circuits or ground faults. These rules add

to or amend the provisions of Article 240. The devices

Single-phase

motors

AC polyphase motors other than wound- rotor

Squirrel cage — other than Design B energy- efficient

Design B energy- efficient

300 175 800 250

300 175 800 250

300 175 800 250

300 175 1100 250

specified in Part IV do not include the types of devices
required by 210.8,230.95, and 590.6.

Synchronous3 300 175 800 250

Wound rotor 150 150 800 150

The provisions of Part IV shall not apply to motor cir- cuits rated over 600 volts, nominal.
FPN No. 1: For over 600 volts, nominal, see Part XI.

Direct current (constant voltage)

150 150 250 150

FPN No. 2: See Annex D, Example D8.

430.52 Rating or Setting for Individual Motor Circuit.

(A) General. The motor branch-circuit short-circuit and ground-fault protective device shall comply with

430.52(B) and either 430.52(C) or (D), as applicable.

(B) All Motors. The motor branch-circuit short-circuit and ground-fault protective device shall be capable of carrying the starting current of the motor.

(C) Rating or Setting.