Specifications

What are Circuit Protection
Devices and how do they
work?
Circuit Protection Devices are manufactured
for use in multiple power strips, boats,
recreational vehicles, battery charges,
welding equipment, portable generators,
agricultural equipment, trucks, passenger and
school buses and off-road construction
equipment.
GENERAL OPERATING PRINCIPLES
Circuit Protectors are single pole thermal
type devices. Basic construction consists of
two terminals, one terminal with a composite
alloy reed to which a precious metal contact
has been attached, and the second terminal
with a precious metal contact. When a circuit
protector is assembled and in the operational
mode, the precious metal contacts rest
against each other. Current flow is from one
terminal through the composite alloy reed to
the contacts and out the second terminal. In
general, the size, material composition and
the way the reed is processed during
manufacturing, coupled with the type of
contacts and terminals, determines the
current rating of the device. Under normal
conditions, circuit protectors are designed to
handle 100% of rated current on a
continuous basis. When the current rating is
exceeded heat will be generated and the
composite alloy reed will bend up,
separating the contacts. The speed at which
this process occurs is dependent on two main
variables, the amount of current in excess of
rating and temperature. The method in which
the breaker is reset depends on the types of
breakers used.
Automatic Reset
Type 1 will cycle continuously during an
over-current condition. The composite alloy
material will bend and separate the contacts
when an over current situation occurs and
return to the run mode as it cools. This
process will continue until the source of the
over-current is removed or corrected.
Modified Reset
Type 2 Unlike the auto reset design, Type 2
has an additional resistive component built
into it which raises the ambient temperature
within the circuit protector. This limits the
number of cycles (less than 10) by not
allowing the composite alloy to cool and
reset the circuit. The circuit will remain
open with less than 1.0 amp current flow as
long as the voltage is applied.
Manual Reset
Type 3 circuit protector introduces a non-
current carrying object between the contacts
when they open. To reset the contacts, an
external button or lever must be activated to
return to normal operation.
Sizing A Circuit Protector
Temperature and percent of rated current
will affect the performance characteristics of
a thermal circuit breaker. These parameters
should be taken into consideration when
specifying which size and type device is
needed for your application. All Pollak
®
circuit protectors are designed to run
continuously at 100% of rated current at
77°F. However, as a general rule you should
size your breaker so that your continuous
current is 75-80% of the rated current of
your circuit protector. For example, if your
application runs at a continuous 8 amps, you
should choose a 10 amp breaker.
Another major factor to consider is
the affect that temperature has on the
rating of the circuit protector. As with
all thermal devices, as temperatures
change the continuous current rating
of the circuit protector changes. As
stated earlier, all Pollak circuit
protectors are designed to run
continuously at 100% or rated current
at 77°F . The bottom chart shows the
effect temperature has on the rated
current for circuit protectors.
CIRCUIT
BREAKERS
Notes: Circuit Breakers vs fuses
Circuit
Breaker
Fuse
Resettable
Cycles
Yes No
Adjustable
Ambient
Compensation
Yes No
Locate
Anywhere
(even under
hood)
Yes No
Permanent
Mounting
Capability
Yes No
41
Copper
Connections
BI-Metal
(Nickel-Copper-Nickel)
Zinc Plated Metal
Housing
or
Nylon Housing.
#10-32 Zinc Plated,
Brass
Steel Hex Nut
Steel Lock
Washers