Obtain detailed information topics such as Carling switch applications, poles, amp ratings, volts, horse power, basic circuit functions, switch types, actuator types, mounting styles, terminations, illumination, agency approvals, and electrical contacts.
Click on a section below to reveal information.
A circuit is the closed loop through which electricity can flow. A closed circuit allows an uninterrupted flow of electricity from the source of power, through the conductor or wire, to the load, and then back again to the ground or source of power. An open circuit will not conduct electricity because either air, or some other insulator has stopped or broken the flow of current in the loop.
Maintained/Momentary Switches
Carling offers a wide range of circuit configurations with both maintained and momentary switch functions. A maintained switch maintains the mode or position to which it is actuated. For example, if switched to the "ON" position, the switch will remain in the "ON" position until it is physically switched to another position.
A momentary switch is a "spring return" switch which automatically returns to its original or at rest position. A simple example of a momentary switch would be a doorbell, which automatically returns back to its resting "OFF" position when no longer actuated.
Carling Technologies' catalogs denote momentary circuits using parenthesis. For example, the doorbell circuit would be represented as (ON)-NONE-OFF, where (ON) is the momentary position.
Normally Open/Normally Closed
Momentary switches can be described as normally open or normally closed, which refers to the switch's original or at rest position. A normally open or N.O. momentary switch has one or more circuits that are open when the switch actuator is at its normal or rest position. An "open" circuit is an incomplete circuit, with "open space" between contacts. Therefore a normally open circuit can also be referred to as "normally OFF".
A normally closed or N.C. momentary switch has one or more circuits that are closed when the switch actuator is at its normal or rest position. A closed circuit is a completed circuit. Therefore a normally closed circuit can also be referred to as "normally ON".
Throw
The throw of a switch is the number of circuit paths that can be controlled by any one pole. Usually the number of "ON" positions that a switch has is the same as the number of throws. A single throw switch (ST) opens or closes a circuit at only one of the extreme positions of its actuator, the most common example being an ON-NONE-OFF switch. A double throw switch (DT) switch opens or closes a circuit at both extreme positions of its actuator, a common example being an ON-NONE-ON switch.
ON-NONE-OFF
The ON-NONE-OFF or ON-OFF circuit is a maintained, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 2 & 3 and 5 & 6.
If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to place the switch to the ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the OFF position, where all switching circuits would be open.
OFF-NONE-ON
The OFF-NONE-ON or OFF-ON circuit is a maintained, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 4 & 5.
If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to place the switch to the OFF position, where all switching circuits would be open. You would press the bottom of the rocker or move a toggle downward to set the switch to the ON position.
(ON)-NONE-OFF
The (ON)-NONE-OFF or (ON)-OFF circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the momentary ON position closes the circuit at switch terminals 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 2 & 3 and 5 & 6.
If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to move the switch to the momentary ON position. Because this is a normally open (N.O.) circuit, when you release the actuator it will automatically return to its normal at rest OFF position, where all switching circuits would be open.
ON-NONE-(OFF)
The ON-NONE-(OFF) or ON-(OFF) circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 2 & 3 and 5 & 6.
If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary OFF position, where all switching circuits would be open. Because this is a normally closed (N.C.) circuit, when you release the actuator it will automatically return to its normal at rest, ON position.
OFF-NONE-(ON)
The OFF-NONE-(ON) or OFF-(ON) circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the momentary ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 4 & 5.
If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary ON position. Because this is a normally open (N.O.) circuit, when you release the actuator it will automatically return to its normal at rest OFF position, where all switching circuits would be open.
(OFF)-NONE-ON
The (OFF)-NONE-ON or (OFF)-ON circuit is a momentary, single throw, two-position switch circuit. In general, for basic unlighted single pole switches, the ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 4 & 5.
If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to move the switch to the momentary OFF position, where all switching circuits would be open. Because this is a normally closed (N.C.) circuit, when you release the actuator it will automatically return to its normal at rest, ON position.
ON-NONE-ON
The ON-NONE-ON or ON-ON circuit is a maintained, double throw, two-position switch circuit. In general, for basic unlighted single pole switches, ON positions close at the circuit at switch terminals 1 & 2 and 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 2 & 3; 4 & 5 and 5 & 6.
If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to set the switch to the first ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the second ON position. This switch circuit does not have an OFF position, where all switching circuits would be open.
ON-NONE-(ON)
The ON-NONE-(ON) or ON-(ON) circuit is a momentary, double throw, two-position switch circuit. In general, for basic unlighted single pole switches, the maintained ON position closes the circuit at switch terminals 2 & 3, and the momentary ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the maintained ON circuit is closed at terminals 2 & 3, 5 & 6; and the momentary ON circuit is closed at terminals 1 & 2, 4 & 5.
If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary ON position. Because this is a normally closed (N.C.) circuit, when you release the actuator it will automatically return to its normal at rest maintained ON position. This switch circuit does not have an OFF position where all switching circuits would be open.
ON-OFF-ON
The ON-OFF-ON circuit is a maintained, double throw, three-position switch circuit. In general, for basic unlighted single pole switches, ON positions close the circuit at switch terminals 1 & 2 and 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2, and 2 & 3; 4 & 5 and 5 & 6.
If the switch is mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to set the switch to the first ON position. You would move the rocker or toggle actuator to the center position to set the switch to OFF, where all switching circuits would be opened. You would press the bottom of the rocker or move a toggle downward to set the switch to the second ON position.
ON-OFF-(ON)
The ON-OFF-(ON) circuit is a momentary, double throw, three-position switch circuit. In general, for basic unlighted single pole switches, the maintained ON position closes the circuit at switch terminals 2 & 3, and the momentary ON position closes the circuit at switch terminals 1 & 2. For basic unlighted double pole switches, the maintained ON circuit is closed at terminals 2 & 3,5 & 6; and the momentary ON circuit is closed at terminals 1 & 2, 4 & 5.
If the switch is mounted vertically, you would press the bottom of a rocker actuator or push a toggle actuator downward to move the switch to the momentary ON position. When the actuator is released, it will return to the center OFF, at rest position. You would press the bottom of the rocker or move a toggle downward to set the switch to the maintained ON position. From this position, you would manually move the rocker or toggle actuator to the center position to set the switch to OFF, where all switching circuits would be open.
(ON)-OFF-(ON)
The (ON)-OFF-(ON) circuit is a momentary, double throw, three-position switch circuit. In general, for basic unlighted single pole switches, the momentary ON positions close at the circuit at switch terminals 1 & 2 and 2 & 3. For basic unlighted double pole switches, the circuit is closed at terminals 1 & 2 and 2 & 3; 4 & 5 and 5 & 6.
If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the first momentary ON position. You would press the bottom of the rocker or move a toggle downward to move the switch to the second momentary ON position. This is a normally open (N.O.) circuit, therefore whenever you release the actuator it will automatically return to its normal at rest center OFF position, where all switching circuits would be opened.
ON-ON-ON
The ON-ON-ON or PROGRESSIVE circuit is typically a maintained, double throw, three-position switch circuit. Most commonly this circuit function is offered in a two-pole configuration where each pole controls a separate circuit. In this configuration in the first position Circuit 2 is ON at terminal 2 & 3; in the mid position Circuit 1 & 2 are ON from terminals 4 & 5 and 2 & 3 respectively; and in the third position Circuit 1 is ON from terminals 4 & 5.
If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the Circuit 2 ON position. You would move the rocker or toggle actuator to the center position to move the switch to the Circuit 1 & 2 ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the Circuit 1 ON position.
The ON-ON-ON circuit can also be a maintained, single pole, triple throw, three-position switch. In this case, a jumper is usually provided between poles at terminals 2 & 4 to link the common terminal 5 with the three output terminals 1, 3 & 6.
If the switch were mounted vertically, you would press the top of a rocker actuator or push a toggle actuator upward to move the switch to the first ON position at terminals 5 & 6. You would move the rocker or toggle actuator to the center position to move the switch to the second ON position at terminals 5 & 3. And you would press the bottom of the rocker or move a toggle downward to set the switch to the third ON position at terminals 5 & 1.
ON-ON-OFF
The ON-ON-OFF is another type of PROGRESSIVE circuit that is a maintained, double throw, three-position switch circuit. Most commonly this circuit function is offered in a two-pole configuration where each pole controls a separate circuit. In this configuration in the first position Circuits 1 & 2 are ON at terminals 5 & 6 and 2 & 3; in the mid position Circuit 1 is ON at terminals 2 & 3, and in the third position both circuits are OFF.
If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the Circuit 1 & 2 ON position. You would move the rocker or toggle actuator to the center position to move the switch to the Circuit 1 ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the OFF position.
A typical application example for this type of circuit would be HEADLIGHTS - RUNNING LIGHTS - OFF.
The ON-ON-OFF circuit is also offered as a maintained, single pole switch in a double pole base. In this configuration Circuit 2 is ON in the first position at terminals 2 & 3. In the mid-position Circuit 1 is ON at terminals 1 & 2, and in the third position both circuits are OFF.
(ON)-ON-OFF
The (ON)-ON-OFF is a third type of PROGRESSIVE circuit that is a momentary, double throw, three-position switch circuit. Most commonly this circuit function is offered in a two-pole configuration where each pole controls a separate circuit. In this configuration in the first position Circuits 1 & 2 are in the momentary ON position at terminals 5 & 6 and 2 & 3; in the mid position Circuit 1 is maintained ON at terminals 2 & 3, and in the third position both circuits are OFF.
If the switch is mounted vertically, you would press the top of a rocker or push a toggle actuator upward to move the switch to the momentary Circuit 1 & 2 ON position. When the actuator is released, it will return to the center Circuit 1 maintained ON position. You would press the bottom of the rocker or move a toggle downward to set the switch to the OFF position, where both circuits would be open.
A typical application example would be OFF - RUN ENGINE - (START ENGINE).
OTHER CIRCUITS
Carling Technologies offers a number of specialized circuits including reversing two position and reversing three position configurations. Specialty hazard circuits and other specialty circuits for transportation industries are also available. Carling also offers four and eight position rotary switches. If you have specialized circuit needs, please contact your Carling Technologies Sales Representative for assistance.
Contacts are the point where a switch throw makes or breaks a circuit. Switch contacts are always found in pairs. The contact that moves with the switch actuator is the movable contact or lever; the contact that is fixed is called the stationary contact.
Contact Materials
Contacts are subject to heat, arcing, corrosion, welding, pitting, and contaminating materials. The most appropriate contact material will differ depending on load type. Carling offers a variety of contact materials ranging from gold for dry circuits (low current circuits that do not produce an arc) to various silver alloys for high inrush loads. The most commonly used contact material is silver. Silver has low resistance and is one of the best conductors for electricity.
Contact Functions
Contact functions can be described as make-before-break or break-before-make.
Make-before-break switches are those that will complete a new circuit before breaking an old one. With this type of function, the next contact is made or closed before the previous contact is broken or opened. This can also be referred to as a shorting type switch. A typical application example for use of this type of function would be a computer switching from AC to a DC backup system.
Break-before-make switches are those that will only complete one circuit at a time, leaving an interval of time between the time one circuit opens and the next circuit closes. This can also be referred to as a non-shorting type switch. In general, all Carling Technologies' switches are break-before-make switches.
Single Break or Double Break
Single break / single make contacts are those that open and close a circuit at only one place.
Double break/double make contacts are those that open at two separate places on a circuit. Double break contacts dissipate heat more readily, providing longer switch life and enabling the switch to handle higher voltages.
Slow Break or Quick Break
When contacts separate, arcing or sparking can occur between the two contacts. Arcing can burn up the contacts and reduce the useful life of the switch. The arc resulting from a DC voltage will be greater and will last longer then the arc from an AC voltage, because DC current has a constant value in relation to ground and zero. Because of constant electrical flow, DC switches should ideally be quick break. Quick break circuits typically require less than 5 milliseconds to make or break. Carling AC/DC toggles and pushbutton switches utilize a quick break design.
AC current has a value that is always rising or falling in relation to zero. Whenever AC current reaches zero (120 times per second) it cannot create a spark. Because of this, AC switches can be either slow or quick break. Slow break circuits typically require 8-12 milliseconds to make or break. Most Carling AC rated switches utilize a slow break design.
Contact Types
Wiping action contacts are "self-cleaning" contacts that wipe or slide against each other when opening or closing a circuit. This wiping action helps prohibit the build-up of any non-conductive deposits on the contacts themselves. Wiping contacts are typically used in AC applications, but are also suitable for low voltage DC applications.
Wiping action contacts can include some limitations on current, voltage, and lifecycle, and they require some form of lubricant, such as grease, to facilitate movement. With repeated arcing, the level of contaminants can increase and be captured by the lubricant around the contact area. This could eventually affect the operation of the switch.
Carling switch series which offer wiping contacts include R , LR , 610/620, 611/621, T, LTA, TG, LTG, TTG, TLG, C, D, DK/EK, 641, 700, and 800.
Butt action contacts press "head-on" against each other when closing a circuit. They are much more versatile than other types of contacts, having the ability to handle multi-purpose loads from dry circuits up to 20 amps, and the ability to modify contact material, thickness or alloying agents. Butt action contacts are suitable for both AC and DC type switches.
Carling switch series which offer butt action contacts include: Contura II & III, Contura IV & V, Contura X & XI, Contura XII, J Series, L Series, RSC, RGS, LRGS, 611/621, 622/632, 651/652, TIL, TIG, TIH, TII, LTIL, LTIG, LTIH, LS, LT, F, G, H, I, MAAOA/215, P, PP, 170/72, P26, P27, 16-3P, and R135.
Roller contacts are a different style of butt action with an over-center, non-teasable mechanism. They are typically used on AC/DC switches that have size constraints. They are an example of a double break style contact where both the line and the load are broken simultaneously.
Carling switch series which offer roller action contacts include 110/216 and 110/316-P.
Knife-blade contacts are a quick-make/quick break , non-teasable variation of wiping contacts usually used on high voltage AC/DC type switches.
Carling's DK/EK switch series offers knife-blade action contacts.
Poles are the number of completely separate circuits that can be active through a switch at any time. A single pole (SP) switch opens, closes or changes connections in a single conductor of an electrical circuit. A two-pole or double pole (DP) switch is often used to open, close, or change connections in both conductors of the same circuit, or in two separate circuits.
Single Throw / Double Throw
The throw of a switch is the number of circuit paths that can be controlled by any one pole. Usually the number of "ON" positions that a switch has is the same as the number of throws. A single throw switch (ST) opens or closes a circuit at only one of the extreme positions of its actuator, the most common example being an ON-NONE-OFF switch. A double throw switch (DT) switch opens or closes a circuit at both extreme positions of its actuator, a common example being an ON-NONE-ON switch.
Carling Technologies uses the standard abbreviations below when referencing a switch's configuration of poles and throws:
SPST: single pole, single throw
SPDT: single pole, double throw
DPST: double pole, single throw
DPDT: double pole, double throw
Available Pole Offerings
Carling Technologies offers switches from one to four poles.
Single pole offerings include the following switch product series:
- Rocker Switches- Contura II & III, Contura IV & V, Contura X & XI, Contura XII, J, L, R, RSC, 611/621, 610/620, 622/632, 651/652, T, LTA, TG/LTG, TLG, TIL, LTIL
- Toggle Switches - LT, F, C, D, 110/216, DK/EK, MAAOA/215
- Push Button Switches- PP, P, 16-3P, 170/172, P26, P27, 110/316P, 641
- Rotary Switches- R135, 700, 800
Double Pole offerings include the following switch product series:
- Rocker Switches - Contura II & III, Contura IV &V, Contura X & XI, Contura XII, J, L, RGSC, LRGSC, 611/621, 610/620, 622/632, TG/LTG, TIG, LTIG, TTG
- Toggle Switches - LT, G, 110/216, DK/EK
- Push Button Switches- 110/316-P, 641
Three-Pole offerings include the following switch product series:
- Rocker Switches - TIH, LTIH
- Toggle Switches - H
Four-Pole offerings include the following switch product series:
- Rocker Switches - TII
- Toggle Switches - I