
MANUAL MOTOR STARTER GUIDE
APRIL 19
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7.4.1 Disconnect means for the motor and branch circuit
acc. to NEC Article 430.101 / CEC Section 28-600
The branch disconnect serves as the primary means for isolating the motor and the electrical equipment from the
power source, often for maintenance purposes. The disconnect means is provided with accessories to allow its func-
tion from outside the enclosure. To meet safety requirements, the disconnect means must be lockable in the off
position and must be visible from the motor location. Manual motor starters can be used as the main branch discon-
nect means when marked “Suitable as Motor Disconnect” and installed on the load side of the branch short-circuit
and ground-fault protective device.
7.4.2 Short-circuit and ground-fault protection for the motor and branch circuit
acc. to NEC Article 430.51 / CEC Section 28-200
Each motor branch circuit requires a device that can protect the motor, the electrical components, and the conduc-
tors in the event of a short- circuit or ground fault. Conventionally, this can only be achieved using either fuses or an
inverse-time (e.g. thermal-magnetic) circuit-breaker. However, through Combination Motor Controller testing, the
available options are expanded to also include recognized instantaneous-trip (magnetic only) circuit-breakers and
manual motor starters, which can offer cost-effective alternatives for customers.
7.4.3 Motor control means
acc. to NEC Article 430.81 / CEC Section 28-500
The controller provides the means for the routine starting and stopping of the motor. Controllers range in complexity
from the very basic manual switches to continuous speed control using variable frequency drives. Depending on the
size of the motor and the type of application, customers can select from a wide variety of motor control options avail-
able from ABB. One critical aspect for selection is to ensure that the control means is properly rated for the type of
load to be controlled, in this case “AC Motor” or “DC Motor” ratings. Not all controllers are suitable for use in motor
applications. Additionally, it is important to consider the electrical durability of the control device, as some devices
suitable for motor control are not designed with this intention (e.g. molded case circuit-breakers).
7.4.4 Overload protection for the motor and branch circuit
acc. to NEC Article 430.31 / CEC Section 28-300
Each motor branch circuit requires a device that can protect the motor, the electrical components, and the conduc-
tors from excessive heating due to motor overloads or failures to start. Although most devices used for short-circuit
and ground-fault protection also offer thermal protection against overheating, very few motor applications allow for
the use of inverse-time circuit-breakers alone to protect the installation against overload conditions (exc. 1 hp or less,
non-automatically started).
7.4.3 Local motor disconnect
acc. to NEC Article 430.102 / CEC Section 28-604
An additional disconnect means is required if the main disconnect means is not within sight of the motor installation
or exceeds a distance of 15 m (50 ft.) in the U.S. and 9 m (29.5 ft.) in Canada. Typically, customers will use enclosed UL
60947-4-1 / CSA C22.2 No. 60947-4-1 manual motor starters or non-fusible disconnects when marked “Suitable as
Motor Disconnect”, since the local disconnect is already positioned downstream from the short-circuit and ground-
fault protective device. However, all devices suitable for the main disconnect means can also be selected for this pur-
pose.
See Chapter 7.1.5 Categorizing manual motor starters, for a list of suitable products for each functional requirement
by Category Code (CCN).