Straight Vs. Slash Voltage Ratings; Short-Circuit Current Ratings; Components Requiring Short-Circuit Current Ratings - ABB MS116 Manual

7.2.3 Straight vs. slash voltage ratings

Short-circuit protective devices with straight voltage ratings (e.g. 480 V AC) can be applied in any circuit, grounded
or ungrounded, where the line-to-line voltage does not exceed the maximum rating specified.
Short-circuit protective devices with slash voltage ratings (e.g. 480Y/277 V AC) can be applied only in solidly
grounded networks where the voltage from line-to-ground does not exceed the lower of the two ratings
(e.g. 277 V AC), and the voltage from line-to-line does not exceed the higher of the two ratings (e.g. 480 V AC). The
lower rating represents the device's interrupting capability per pole.
Depending on the how they are applied, manual motor starters carry either straight (Δ) or slash (/) voltage ratings.
Rating type
Manual Motor Controller
Manual Motor Controller, Suitable as Motor Disconnect
Manual Motor Controller, Suitable for use in Group Installations
Manual Motor Controller, Suitable for Tap Conductor Protection in Group Installations
Manual self-protected Combination Motor Controller (Type E for UL)
Combination Motor Controller (Type F for UL)
Protection of ABB Micro drives
1)
MS132/MO132 and MS165/MO165 only

7.2.4 Short-circuit current ratings

Short-circuit current ratings (SCCR) are tested values for motor control and protection devices to ensure safe reac-
tion during short-circuits and ground faults. Since even low-level faults are capable of producing incredible amounts
of energy, unprotected equipment can easily cause damage to the installation and endanger personnel within close
proximity. Short-circuit current ratings have been mandatory for industrial control panels since 2006.
A complete list of ABB's tested SCCRs can be accessed online through our SOC selection tool
(http://applications.it.abb.com/SOC/page/selection.aspx).

7.2.5 Components requiring short-circuit current ratings

All power circuit components for industrial control panels are required to have marked short-circuit current ratings
expressed in kiloamperes and voltage. This includes devices such as:
−
Disconnect switches
−
Branch circuit protective devices
−
Branch circuit fuse holders
−
Load controllers
−
Motor overload relays
− Terminal blocks
−
Busbars
ABB manual motor starters are tested for short-circuit current ratings in a wide variety of applications. SCCR values
for manual motor starters may differ depending on how they are applied. See Chapter 7.1.6 Selecting the right Short
Circuit Current Ratings (SCCR) level for your UL application for more guidance regarding the selection.
APR I L 19
MA N UA L MOTOR START ER G UI D E
Table 23: Straight vs. slash voltage ratings
Maximum
voltage
600 Δ
600 Δ
600 Δ
1) 600 Δ
600Y/347 V
600Y/347 V
480Y/277 V
5 9/8 0