Specifications

30
While some thermal-magnetic circuit breakers have an
adjustable trip curve, the adjustment is limited. Circuit breakers
with a solid state trip unit, on the other hand, typically have
multiple adjustments.
In the past, choosing the variety of circuit breaker types needed
for many applications required selection of circuit breakers
with varied designs, locking users into extensive spare parts
requirements. In response to this problem, Siemens developed
the VL global family of molded case circuit breakers.
VL Circuit Breakers Siemens VL circuit breakers have a modular design that
provides maximum flexibility. VL circuit breakers are available
with continuous current ratings up to 1600 amps. Each circuit
breaker frame is compatible with three trip unit models, Model
525 Thermal-Magnetic Trip Unit, Model 555 Electronic Trip
Unit, and Model 586 Electronic Trip Unit with Liquid Crystal
Display (LCD). In addition, only two families of common
internal accessories are needed to cover the complete range of
VL breakers.
!
!
!
DANGER
DANGER
PELIGRO
ON
OFF
O
I
Typ
e/Ty
po
NNG
Fra
me
M
G
!
!
!
DANGER
DANGER
PELIGRO
ON
OFF
O
I
Typ
e/T
ypo
NNG
Fra
me
M
G
ON
OFF
O
800
A
I
Typ
e/Ty
po
NMG
!
!
!
DANG
ER
DANG
ER
PELI
GRO
Fra
m
e M
G
ON
I
O
OFF
600A
F
ra
m
e - LG
Typ
e/Tipo
150A
OFF
O
I
ON
Typ
e/T
ipo
NDG
Fra
m
e D
G
250A
OFF
O
I
ON
Typ
e/Tipo
NFG
Fram
e
FG
ESC
150A
OFF
O
I
ON
Typ
e/Tipo
NDG
Frame
DG
VL Circuit Breakers
WL Circuit Breakers The circuit breakers discussed thus far in this course are molded
case circuit breakers that conform to the UL 489 specification.
This specification also covers a category of molded case circuit
breaker commonly referred to as an insulated case circuit
breaker (ICCB). ICCBs are generally used in switchboards and
may be fixed mounted or drawout mounted.