OCPD Construction
A fuse designed to trip with no intentional delay
What is non-time-dealy
Overcurrent protection devices are rated in amperes, interrupting rating and this
What is voltage?
True/False - All fuses of the same class irrespective of manufacturer must be identical in physical dimension.
What is true
This type of OCPD is designed to provide an extra level of protection for specific equipment and is not permitted to provide feeder or branch-circuit overcurrent protection.
What is supplementary?
It is important to know this quality/detail for a circuit breaker to ensure it will physically be able to install within a given panelboard.
What is frame size?
This type of circuit breaker senses current flow in two ways so that it will open under both an overload condition and a short circuit/ground fault condition
What is a thermal magnetic breaker?
These types of fuse holders ensure that only current-limiting fuses are used for replacement purposes
What is rejection style?
To avoid an OCPD from being significantly damaged from a fault current (and potentially not functioning properly to open circuits) it is vital that the interrupting rating of the device be equal to or greater than this.
What is expected available fault current (AFC) at that location?
These types of fuses are used to provide protection for power electronic components, such as a power electronic drive for motor control.
What are high speed?
In general, fuses installed in applications over 150 Volts to ground are required to contain a disconnecting means located here.
What is on the supply side?
This component (typically a sand type material) of a fuse helps extinguish the internal arc initiated by the melting/vaporizing of one or more of the links
What is filler?
What is a photovoltaic source circuits and output circuits?
A diagram used to determine the trip time of an overcurrent device where current is plotted on the x axis and time is on the y axis.
What is time-current curve?
This type of adapter is used with plug style fuses to ensure replacement fuses are not rated higher than the fuse being replaced.
What is as Type S Fuse Adapter
A voltmeter connected across an energized fuse that is in good working condition should read this many volts
What is zero Volts?
Time delay fuses are constructed with two distinctly separate types of elements connected in this configuration
What is series?
Fuses typically have an interrupting rating of this or higher.
What is 200 kA?
Overcurrent devices main function is to protect these two items in an electrical system from harmful overcurrent events
What are conductors and equipment?
The main differences between molded case circuit breakers (MCCB) and this category of branch circuit overcurrent device is cost, physical size, amperage range, and the priming function required to close the circuit breaker.
What are insulated case circuit breakers or low voltage circuit breakers?
In general, services with fuses larger than this are required to be equipped with fuses that clear in less than 0.07 seconds or be equipped with ARMS
What is 1200 Amps? - In Wisconsin, we remove this requirement and any ARMS system installed is on a voluntary basis
Current limiting overcurrent protection devices are designed to open in this amount of time so that damage to equipment/wire and potential arc flash/blasts can be avoided.
What is less than 1/2 cycle or .008 seconds?
In general, a dual-element time-delay fuse with an ampere rating of 15 amps will hold an overload of 75 amperes for this long
What is 10 seconds? Fuses typically hold 5x their rating for up 10 seconds allowing motors to start without tripping
This fuse class known for its distinctive shape is sometimes referred to as "Charlie Chaplin" because the shape is reminiscent of his hat
What is CC?
This type of OCPD is application limited and does not have an overload sensing element. They only provide short circuit or ground fault protection in motor branch circuits.
What are motor circuit protectors or instantaneous trip OCPD?
50 kVA Transformer with 480V primary, 208/120V secondary. Primary current = 60A Secondary current = 138 A
If primary and secondary OCPD's are used to protect the transformer, the maximum secondary OCPD is this amperage value.
What is 150A?