L Rating (switches)

Denotes the ability of a switch to handle the initial high inrush of Tungsten Filament Lamp on AC Voltage only.

LED

Light Emitting Diode

Let-through Current

The actual fault current passing through a protective device as compared to the current available to the device.

Life Expectancy (Useful Life)

Depends upon the end life criteria for a specific application. In order to determine you failure criteria, the following parameters should be known: dielectric strength, duty cycle, mechanical breakdown, contact resistance, insulation resistance, operating force. Life expectancy is normally experienced in minimum switch cycles before failure.

Load (Electric)

The amount of electric power delivered or required at any specific point or points on a system. The requirement originates at the energy consuming equipment of the consumers.M

Make-Before-Break

Switches that complete a new circuit before breaking an old one.

Maintained Switch

A switch that maintains the mode or position to which it is actuated.

Micro Gap

A symbol appearing as a part of the switch rating that indicates a contact gap of less than 3 millimeters.

Momentary Switch

A switch that automatically returns to its original or at rest position.N

Normally Closed

Often abbreviated N.C., indicates that the circuit is closed when the switch is not operated. Activation of the switch causes the circuit to open.

Normally Open

Often abbreviated N.O., indicates that the circuit is open when with switch is not operated. Activation of the switch causes the circuit to close.O

Ohm

The unit of measurement of electrical resistance. The resistance of a circuit in which a potential difference of 1 volt produces a current of 1 ampere.

Ohm's Law

The mathematical expression which shows the relationship between current (I), voltage (V), and resistance (R). Ohm's Law shows that as resistance gets higher, the current gets smaller, and vice versa.

R = V/I

I = V/R

V = IR

Open Circuit

An electrical circuit that will not conduct electricity because either air, or some other insulator has stopped or broken the flow of current in the loop.

Operating Force

Also known as Actuation Force, the force required to transfer a switch from one position to another.

Overload Current

The current value in excess of the rated current of the protective device.P

Pole

The number of completely separate circuits that can be active through a switch or simultaneously protected by a circuit breaker at any one time.

Push-On/Push-Off

An alternate action switch, often used on lamps, vacuum cleaners, etc. When pushed, the circuit closes. When pushed again, it opens. Often called 'Push-Push.'Q

Quick Break/Quick Make

Switches designed to make or break circuits in less than 5 milliseconds to make or break. Recommended for use on DC circuits.R

Resistance

The opposition a conductor offers to current.

Resistive Load

Load that offers resistance to the flow of current. Examples of resistive loads: electric heaters, ranges and ovens, toasters, and irons. If the device is supposed to get hot and doesn't move, it's mostly likely a resistive load.S

Short Circuit

A connection of comparatively low resistance accidentally or intentionally made between points on a circuit between which the resistance is normally much greater.

Single Break / Single Make

Contacts that open and close a circuit at only one place.

Single Pole - SP (switches)

A switch device that opens, closes, or changes the connection of a single conductor in an electrical circuit.

Single Throw (ST)

A switch that opens, closes or completes a circuit at only one of the extreme positions of its actuator.

Slow Break/Slow Make

Switches designed to make or break circuits within e 8-12 milliseconds. Typically used for AC applications.

Snap-Action

Non-teasable switch action having unstable equilibrium so that it must be either 'ON' or 'OFF'. Can also be referred to as 'Push-Push.'T

Terminal

1) The point at which electrical connections are made. 2) The mechanical device at such a point in a circuit, as at the end of a wire or cable, by means of which an electrical connection may be made.

Time Delay

The introduction of an intentional delay to the opening function of a protective device.

Total Clearing Time

The time elapsing form the initiation of overload current to final current interruption.U

Ultimate Trip Current

The minimum value of current that will cause tripping of a protective device.V

Volt (V)

The electromotive force which, if steadily applied to a circuit having a resistance of one Ohm, will produce a current of one Ampere.

Voltage

Electric potential or potential difference expressed in volts

Voltage Drop

A conductor's voltage reduction due to resistance.

Voltage of a Circuit

The electric pressure of a circuit in an electric system measured in volts. It is generally a nominal rating based on the maximum normal effective difference of potential between any two conductors of a circuit.

Voltage Rating

The maximum voltage at which a device is designed to operate.

Voltage Trip

A protective device that is factory calibrated to trip at a predetermined voltage value.W

Watt

The unit of electrical power required to do work at the rate of one joule/second or the power consumed when one ampere flows with one volt applied to a circuit.

Wiping Action Contacts

Self-cleaning contacts that wipe or slide against each other when opening or closing a circuit.