Businesses are becoming increasingly more intelligent about 
the way they consume energy. Industrial and Commercial energy 
consumers are continuously looking for practical and efficient 
methods of measuring their energy usage while simultaneously 
ensuring any possible downtime is minimized. At Siemens we 
understand those needs and we have developed products and 
solutions to help energy consumers achieve their goals.
One of our solutions begins with our world-class WL Circuit 
Breakers. The WL line-up of breakers developed by Siemens 
combines decades of patented circuit breaker protection 
experience with the latest technology in circuit breaker 
performance and communication.
A good example of our innovative technology is, Dynamic 
Arc-Flash Sentry® (DAS). DAS is an option that allows users 
the ability to automatically lower the down-stream available 
fault current when facility personnel are nearby the electrical 
equipment. Helping our customers provide a safer work-place 
environment is an important part to our overall solutions.
Other valuable aspects that complement our solutions are the 
WL circuit breaker’s ability to gather energy and environmental 
data and send it to a central or remote monitoring network 
system. You’ll find these capabilities and more when you take 
a closer look at WL circuit breakers features within this guide.
WL Circuit Breaker Features and Benefits
•  3 frame sizes: Three frame sizes that cover a wide range of  
  continuous current ratings allow for flexible exchange of 
  breakers to other compartments and reducing the footprint 
  of the breaker enclosures
•  Ready-to-close indication: Built-in check points of the 
  breakers mechanical operator provide an additional layer of  
  safety and external controls by inhibiting the breaker from 
  closing until certain conditions are satisfied
•  100% rating: All model breakers are designed for continuous  
  operation at their maximum current ratings without de-rating  
  the frame or use of forced air
•  High-efficiency: Low loss of energy flowing through the 
  breaker reduces the operating costs
•  Bi-directional feed: Top or bottom supply feed without any  
  hardware configuration changes.
•  Rogowski coil sensing: Full range sensing without tap 
  terminals or exchanging sensors to match load change 
 requirements.
•  Modular trip unit: Upgrading to a higher current rating, 
  adding ground fault, power monitoring or communication 
  is cost effective and expandable using separately 
 available modules. 
•  Common accessories: Interchangeable accessories makes up 
  grading easy and readily available
Practical solution
Applications
The WL line of power breakers are protecting electrical 
distribution applications like waste water treatment, industrial 
plants, hospitals, transportation systems and data centers just 
to name a few. Yes, mission critical applications trust the Siemens 
WL circuit breakers to operate safe and reliably. The compact 
modular design provides higher power density in a section or
line-up of distribution gear. Components like spring-charging 
motor, shunt trips, and trip units are common across the entire 
line of breakers. That allows users the ability to stock fewer 
spare parts or exchange options if necessary. Common options 
and accessories also make learning how to order, maintain 
and operate the WL much easier than most breakers on the 
market today. 
WL circuit breakers are manufactured and performance tested to 
comply with UL489 and UL1066 standards for listed products.
UL489 classification type WL breakers are generally intended to 
provide service entrance, feeder, and branch circuit protection in 
accordance with UL489 Molded Case Circuit Breaker Standard 
for Safety. Usage and installation of these breakers are normally 
related to UL891 Switchboard or UL508 Industrial Equipment 
Listed apparatus. Certain options and maintenance capability 
may be limited to or not available as in the UL1066 Listed 
breakers. For listing details refer to UL File# E231263
UL1066 classification type WL breakers are generally intended 
to provide main and feeder circuit protection in accordance with 
UL1066 Low-Voltage Power Circuit Breaker Standard for Safety. 
These breakers were also performance tested to comply with 
ANSI/IEEE C37.13, C37.16, C37.17, and C37.50. Throughout this 
document any reference to UL1066 will also mean ANSI Certified. 
Usage and installation of these class breakers are normally related 
but not limited to UL1558 Switchgear (switchboards) listed 
apparatus. Certain options and ratings may be limited to or not 
available as in the UL489 Listed breakers. For listing details refer 
to UL File #240124 and 240232.
Low Voltage Circuit Breaker
Introduction
2 WL Circuit Breaker selection and application guide