Langir Normally Closed Push Button Switch to Skyrocket Your Business

Langir is the premier manufacturer of normally closed push button switch in China. Langir Nomally closed push button switch, usually called NC push button switch. When you press, the switch break contact; when released, it makes contact.

Until now, Langir normally closed push button switch has 4 types of materials optional-aluminum, brass nickel-plated, golden plated & 304 and 316L stainless steel. For example, If your device is black color, you choose anodized aluminum black color, they will match very well.

In the emergency braking system, when someone is hurt or in an emergency, push the emergency stop push button switch, the system will stop immediately or relevant people will come to help you. Langir emergency stop push button switch will protect your safety.

The above-listed items all have the NC or 1NO1NC function. Langir normally closed push button switch should be found in railway, hospital, elevator, door etc which are installed in the panel mount.

Langir normally closed push button switch already passed through lots of certificates and test reports such as CE, ROHS, REACH, IP65, IP67, IP68,IP69K, IK10 and so on. Each switch has got 365 days quality warranty when they are delivered.

Langir electric will provide not only the pushbutton switches themselves, but also the technical support and our team services. Welcome your any consulting or doubt, you will get our quick reply within 8 hours.

Normally Closed Push Button Switch – FAQ Guide

In this guide, you will discover a lot of things about a normally closed push button switch.

You will learn about its types, components, and the quality standards you should look for when making a purchase.

Also, you will read about some interesting facts about this type of switch and the many advantages it can give.

So let’s read this guide to help you make a smarter decision when shopping for normally closed push button switches.

1. What is a normally closed push button switch?

A normally closed push button switch is one of the many types of push button switches. It is also called a push to break switch. Sometimes people will call it push button nc.

This works even when the nc momentary switch is not pressed.  The electricity flows allowing the switch to operate.

When the normally closed push button switch is pressed, the circuit is broken therefore stopping the operation. A normally closed push button switch can be momentary, latching, electric, or pneumatic.

Fun Fact: In 1958, the movie “The Monsato House of the Future” features their future vision of a modern house with many installed push button switches for different functions.

In this movie, the happy wife pushes the buttons to reveal the hidden compartments in the kitchen.

It also features panels with push buttons that controls the home which is similar to the “smart homes” we have today.

1958 The Monsanto House of the Future

2. What is the history of the normally closed push button switch?

The development of normally closed push button switch could be attributed to John Henry Holmes who invented the “quick-break technology” in 1884.

This technology replaced the arc lamps that were used for street lights succeeding the gas illumination street lights. Arc lamps emit dangerous UV rays, their light flickers, electrodes frequently changed and produces a buzzing sound.

This is the main reason why the quick-break technology immediately took over and cities started to change their arc lamps.

In the 1910s, as the electricity grid expanded thus paving way for the simple light push buttons in homes. The push button technology became available to a wide variety of consumer items in the 1950s including cars.

The 1960s marked the period where push buttons are used in household appliances such as cooking stoves, washing machines, job automation, etc.

The Holmes light switch

3. What is the symbol for a normally closed push button switch?

This illustration below shows the contacts with circles that touch the electric circuit. When the push button is pressed, the contacts break away from the circuit.

Therefore, this stops the operation of the push button switch.

4. What is the difference between a normally closed push button switch and a normally open push button switch?

A normally closed push button switch has its contact on the electrical circuit in its default state. While a normally open push button switch is the opposite.

A normally open push button switch makes its contact on the electrical circuit when the push button is compressed. And it is not making contact with the electrical circuit during its default state.

Symbol for normally closed push button switch & normally open push button switch

5. What are the advantages of using a normally closed push button switch?

There are many advantages of using a normally closed push button switch. Here are some of the common advantages why people choose the NC push button switch:

• Double function for one single switch – Many applications can benefit from its double functionality which are switching and non-switching functions.
• High level of safety – It has a shorter operating time compared to other switches and although the difference is only in seconds, this is very important in emergencies as every second counts.
• Minimal contact bounce – Unlike in other types of switches where you have to push the button all the way down for it to operate, a normally closed push button switch doesn’t necessarily need more push pressure to break a circuit flow and stop operation.
• It stops the machinery if it fails – Another advantage in critical situations is when it fails, typically the machinery stops altogether which prevents possible accidents or safety risks.
• Easier to identify – As a normally closed push button switch is commonly used for emergency stop button or alarm switch, people would already have an understanding of what it is used for and can immediately identify it amongst other switches as it would have the easily identifiable bright color red.
• Affordability – With wide array of options and price range, you will be able to find the one suitable for your needs and your preference.

6. What are the examples of a normally closed push button switch?

There are many examples of normally closed push button switches. They can be found in homes, commercial, and industry use.

Some of the commonly known normally closed push button switches are the following:

• Refrigerator light
• Alarm switches
• Fail-safe circuits

Examples of normally closed push button switch

7. How do you tell if a switch is a normally closed push button switch?

The easiest way to identify if a nc switch push button is a normally closed switch is during its default state.

Just by simply observing it visually, you will notice if it is functioning while the push button is not being pressed.

Another way is to test it by pushing the button.

And when you pushed the button, the operation stops, or the equipment where it is installed stops working.

8. What are the components of a normally closed push button switch?

Normally closed push button switch components

The components of a normally closed push button switch are the same as a regular push button switch.

The main difference is the internal mechanisms are different from a normally open push button switch.

Here are the common components of a normally closed push button switch:

1. Actuator – This is the control component that is immediately noticed since it sometimes displays a symbol or logo and is sometimes illuminated by colored lights.
2. Lens or illumination – This is the lighting of a push button switch which is usually an LED light.
3. O-ring – This component which is usually made of a rubber material helps seal the components to avoid ingress of substances that could harm the switch.
4. Hex Nut – This usually provides a secure and stable mounting of the push button switch on the mounting panel.
5. Threading – These small dents or grooves provide added stability for mounting.
6. Base – This box-shaped component houses the connectors for some types of push button switches.
7. Terminals – These are the immobile short metal rods located below the pushbutton switch where the positive and negative electrical wirings are connected.
8. Silver contacts – These are inside the normally closed push button switch.

9. How many available actuators does a normally closed push button switch have?

Similar to any push button switch, the normally closed push button switch has the following types of actuators.

1. Flat actuator – As the name denotes, the appearance of this actuator is flat or leveled.
2. High actuator – This actuator is a bit lifted or elevated.
3. Domed actuator – This actuator resembles a dome or a hemispherical shape.

10. What are the color options for a normally closed push button switch?

The color options available for a normally closed push button switch are many.

Some of the usual colors you can find are red, blue, and green.

Other colors such as yellow, white, and orange.

Some manufacturers also sell push button switches with LED that changes colors like tri-color normally closed push button switch.

Colors of normally closed push button switch

11. How many illumination options are there for a normally closed push button switch?

Normally closed push button switch has around four common illumination options you can choose from depending on the manufacturer.

1. Non-illuminated push button switch– The push button do not have any illumination however, you can find kinds that have colors.
2. Dot illuminated push button switch – You will notice a small circular lens that emits light located either at the center or along the side of the push button switch.
3. Ring illuminated push button switch – These types of illuminated switch has a ring-shaped lends that emits light.
4. Symbol illuminated push button switch – In this type of illuminated switch, there’s a symbol or logo displayed on the push button that can be customized.
5. Backlit led with label kit

12. What are the diameter sizes available for a normally closed push button switch?

The diameter sizes for a normally closed push button switch varies depending on the manufacturer, the seller, and sometimes it depends on where you are located.

The common diameters which are available are the following:

• 10 mm
• 12 mm
• 16 mm
• 19 mm
• 22 mm
• 25 mm
• 30 mm

Bigger diameter sizes could be available from some manufacturers.

13. What output terminals does a normally closed push button switch have?

There are two common output terminals available for a normally closed push button switch which are the following:

• Screw-type output terminals – When connecting the electrical wires to these terminals, you may need a screwdriver to attach them.
• Solder-lug type output terminals – In these types of output terminals, connecting the electrical wires would need a soldering iron.

Pin terminal and screw of normally closed push button switch

14. How long does a normally closed push button switch last?

A high-quality 12v push button switch normally closed can last up to 2,000,000 mechanical life cycles.

The mechanical life cycle determines the durability of the internal parts against the corrosion caused by the electrical sparks.

Other normally closed push button switches that cost cheap may have a lower mechanical life cycle and lower quality therefore shorter life span.

15. What position does a normally closed push button switch is usually in?

A normally closed push button switch when in default mode could be either in the “on” or “off” status.

The contacts touch the electrical circuit which means the circuits remain closed.

Therefore, the electricity flows freely but it stops or it opens the circuit when the actuator is compressed.

Normally closed position with light bulb

16. What are the mounting options for a normally closed push button switch?

The common mount options for a normally closed push button switch are the following:

1. Threaded body mounting option – These push button switch models have depressions along the sides that helps fasten the hex nut tightly.
2. Snap-in mounting option – This provides an easier way to install the push button switch which is done by simply pushing it to the mounting hole hence the term “snap-in”.
3. Surface mounting application – These switches are also known as SMD which refers to the method of termination and are often installed on the surface.
4. Panel mounting application – The mounting of the push button switch is simply done through the front or surface side of the panel.
5. Rear mounting application – The opposite of the surface mounting application, the installation of the push button switch is done through the rear side or backside of the panel.

17. What are the electrical terminations available for a normally closed push button switch?

Electrical termination is the work required to connect the switch’s output terminals to the electrical wires.

This varies according to the type of output terminal, switch, type of wiring cable, and application.

The following are the most common type of electrical termination for a normally closed push button switch.

1. Crimp – Usually, the wire is stripped of its outer cover and it is attached to the terminal using a crimp tool.
2. Plug-in – This switch would have an attached valet with pins on the other end to plug into a slot.
3. Screw – The electrical wires are screwed into the output terminals to be connected.
4. Solder – Attaching the electrical wires will need a lead melted by a soldering iron.

Other electrical termination terms that are good to know:

5. Through-hole or thru-hole – The output terminals are soldered into the holes on the circuit board.
6. Clamp or Cage – The pealed wire is inserted into a slot and secured by a clamp inside.

Crimp tool

18. How do you install a normally closed push button switch?

It is simple and easy to install a normally closed push button switch.

You will need the following prepared to install the switch properly.

• A normally closed push button switch
• For screw-type terminals, you will need a screwdriver
• For solder type terminals, you will need a soldering iron and lead
• A mounting panel and panel cutout
• A hand drill to make a hole or a hole saw

Here are the steps you can follow for the DIY installation.

1. Take the panel and trace the panel cutout where you will be mounting the push button switch.
2. Cut a hole following the cutout tracing using a hand drill.
3. Check if the push button switch fits properly on the mounting hole.
4. Remove the hex nut from the switch.
5. Then mount the push button switch securing the hex nut tightly.
6. Connect the electrical wirings on each of the terminals.
7. Lastly, test the switch if it’s functioning properly.

For complex installations, you may need to consult a professional electrician to do the installation for you.

19. Why do we use normally closed push button switch instead of other switches?

Normally closed push button switches are preferred by some industries instead of other push button switches.

For example, a stop push button is a safety device and is wired as a failsafe.

This means that it reverts the machinery into a safe condition when malfunction happens.

If the stop push button is not wired properly, the operator will not function.

This is the reason why a 12v momentary switch normally closed is preferred in this type of situation.

20. Why is a normally closed push button switch called push-to-break?

The term “push-to-break” defines what happens when the push button switch normally closed is pressed.

The contacts will no longer touch the electrical conductor when this happens.

It is the opposite of a push to make a switch where the condition is reversed.

21. What are the types of materials used to make a normally closed push button switch?

You may find many variations of the normally closed push button switch and they are usually made from approved materials.

The outer parts of the body are usually made of the following:

1. Stainless steel
2. Aluminum (anodized)
3. Nickel
4. Zinc-aluminum
5. Gold-plated
6. Brass nickel-plated

While the inside parts are usually made of the following

1. Copper
2. Polycarbonate (lens)
3. Silicone
4. Nitrile

The terminals are usually made of the following

1. Silver alloy
2. Silver-plated brass
3. Copper

22. Is a normally closed push button switch a momentary press switch?

Yes, you are correct.

There are normally closed momentary switches.

These normally closed momentary push buttons will need consistent pressure on the actuator.

When the pressure is taken off, it returns to its “on” or “off” state depending on how it was designed to function.

Except push button momentary switch normally closed, you could find latching Normally closed push button switch as well.

23. What is an electromagnetic normally closed push button switch?

An electromagnetic normally closed push button switch is normally used for equipment that contains electromagnets or in an electromagnetic environment.

These types of push button switches are specially designed to handle the effects of a variable electromagnetic field.

Some of the examples of electromagnetic devices are the following:

• Generators and motors
• Electric bells or door buzzers
• Loudspeakers
• Valve actuators

24. What is a waterproof normally closed push button switch?

A waterproof momentary switch normally closed is developed to withstand water ingress and as well as water submersion in a short time.

These types of push button switches are best recommended for areas with a high chance of water exposure.

25. What is a weatherproof normally closed push button switch?

A weatherproof normally closed push button switch is designed to endure the changes in weather and the outside harmful elements.

Because of these features, these push button switches can be mounted in an outdoor area.

26. What is a chamfered head normally closed push button switch?

A normally closed push button switch with a chamfered head has a bevel cut around the edge of its head.

They can be easily identified because of their shape which usually has a ring illumination design.

This distinctive shape is preferred for control buttons, limit buttons, reset buttons, start buttons, or control switches.

Chamfer head normally closed push button switch

27. What is a normally closed push button capacitive switch?

A normally closed push button capacitive switch is flat-headed switches which are best used for touch sensor switches.

These types of switches are used in many applications as well such as food processing types of machinery, laboratory, and medical equipment.

You can also find them in domestic applications such as different appliances, elevator control panels, or vending machines.

28. Is there a normally closed push button LED switch?

Yes, there are normally closed push button switch with LED.

These types of push button switches are illuminated which are available in different colors.

You can also find those with backlit label designs that can be customized which depends on the manufacturer.

29. What is a dual-LED normally closed push button switch?

A dual-LED normally closed push button switch would typically emit two different light colors whenever you push the button.

The colors could indicate if the circuit is either open or closed.

In this case, a normally closed push button switch would display color in its default state and another color when the actuator is pressed down.

30. Is there a tri-color normally closed push button switch?

Yes, there are normally closed push button switches that have three different colors.

Similar to dual-LED, it emits light with colors and this time there are three colored lights.

Each color can indicate different types of functions.

The available colors are red, green, blue, yellow, orange, and white.

31. Is there a big size normally closed push button switch?

Yes, there is.

This type of push button switches typically measures 25 mm in diameter or larger.

These are usually preferred for bigger types of machinery or industry operations.

32. What is a normally closed push button big current switch?

These heavy-duty push button switches can handle up to 21 amperes of current.

They are commonly used for installation where a high amount of current is involved.

33. What is a normally closed push button piezo switch?

A normally closed push button piezo switch would normally have a flat head either illuminated or non-illuminated.

Other types have concaved heads or dot-illuminated.

Piezo switches are ideal in rough environments and consume a low amount of electricity.

34. Is there customization available for a normally closed push button switch?

Yes, some manufacturers offer customization of the push button switch you like.

You can select from the approved materials available to make your push button switch such as stainless steel, brass nickel-plated, or golden-plated.

There is also customization available for the type of illumination you prefer for your push button switch.

There are also mounting options available such as pc, panel mount, rear mount, etc.

35. Why do we use a normally closed push button switch in a control circuit?

Push button switches are used in control circuits since they are typically larger and more visible.

It provides easy operation than other types of switches.

You simply have to put your finger over it or press it, and no need to pull or twist.

They are also simple and straightforward when wiring them.

You have the option to wire for single function or multi-function.

36. Why do we use a relay for a normally closed push button switch in a control circuit?

A relay is an electrical device that converts a small electrical supply into a larger electrical supply.

It leverages the weak electrical input to a stronger electrical current.

Relays act as an amplifier of the electric current supply and are flexible for use in both simple and complex circuits.

Even for applications that do not require a relay, it still can be very beneficial.

Relays are cost-efficient because it lessens the need to purchase high-amperage switches or wirings.

It also takes up less space unlike when a control circuit is without it.

Relays also reduce the size and weight of the casing and allow you to fit more functionalities into the case.

37. What type of relay can be used for a normally closed push button switch?

A normally closed push button switch typically uses a relay that handles low electricity.

Relays handle a small amount of electricity typically below 5 kilowatts.

While contactors are commonly used for stronger electricity above 5 kilowatts.

Other types of relays that may be used are the following:

1. Coaxial relay
2. Force-guided contact relay
3. Latching relay
4. Machine tool relay
5. Mercury relay
6. Mercury-wetted relay
7. Multi-voltage relays
8. Overload protection relay
9. Polarized relay
10. Reed relay
11. Safety relays
12. Solid-state contactor
13. Solid-state relay
14. Static relay
15. Time delay relay
16. Vacuum relays

38. Can you use a contactor in a normally closed push button switch circuit?

Yes, you can.

One of the examples is the power contactors which are usually installed in power circuits for its on and off controls.

Other uses of contactors are for the operations of motors, machines, and many others.

There are also auxiliary contactors which are the regular and low-power relay.

It can be used as a stand-alone contactor or with another contactor hence the name auxiliary.

These types of contactors are not used for switching loads however they have controls for activation or deactivation functions instead.

39. How do you order an electrical contactor for a normally closed push button switch?

When ordering a contactor for a normally closed push button switch, you will need to mention the type, model, make, and number of NC contacts.

You may also need to mention the operating voltage of the coil and AC/DC such as the following:

• 12 volts
• 24 volts
• 110 volts
• 230 volts
• 440 volts

40. How do you connect a contactor to a normally closed push button switch circuit?

Depending on the purpose, a contactor can be installed by using a simple diagram below.

You may require two push button switches, one normally open and the other one is the normally closed push button switch.

You will be connecting a wire to connect the two push button switches.

Then wire the normally open switch to the contractor as this will act as your start button.

While the normally closed push button switch will function as the stop button.

41. What is the electronics specification of a normally closed push button switch?

The electronics specification of a normally closed push button switch is usually SPST or Single Pole Single Throw.

It is a simple on-off switch where the terminals are normally connected or in a closed circuit.

42. What are the forms of contacts for a normally closed push button switch?

There are around 23 forms of contacts all in all.

However, the following are the forms of contacts applicable to normally closed push button switch.

1. Form B – This contact is also called “break contact” or normally closed contacts.
2. Form C – These contacts are also called “changeover” or “transfer” contacts which include a pair of normally closed contacts where both connections are briefly open within the same operated device just like in electrical switches.
3. Form D – Also called “continuity transfer” which is similar to Form C but different in its transition order where three terminals are connected briefly.
4. Form Y – This is called double break contacts which similar to two Forms B arranged in a mechanically linked series and are controlled by a single actuator.
5. Form Z – This is also known as double-make and double-break contacts which would have two normally open and two normally closed paths with a similar arrangement as with Form Z.

43. Can you use a normally closed push button switch on the ignition?

Yes, you can.

A simple ignition switch with two wires can have a normally closed contact.

They are also used for alarm signals and kill switches.

44. Can you use a normally closed push button switch as a motor starter?

Yes, definitely.

A pushbutton can be used in starting or stopping motor machinery.

You will see two or three push button switches that operate the motor equipment.

45. What’s an example diagram for a normally closed push button switch?

A normally closed push button switch’s diagram may have different variations depending on its purpose and use.

Here’s one example:

46. What are the amp ratings for normally closed push button switches?

An ampere rating determines the electrical current value for every switch.

This electrical current value is dependent on the allowed conditions specified by the manufacturers.

There are different amp ratings in switches which can be from 6 Volts up to 240 Volts or higher.

It is important to use a higher amp rating push button switch than the voltage required by equipment where it will be mounted to avoid failing or overheating.

47. What is the resistance of a normally closed push button switch?

The resistance of a normally closed push button switch is typically near zero or 0.1 ohms.

48. How do you check the resistance of a normally closed push button switch?

Using an ohmmeter, you can check the resistance of a normally closed push button switch. Here’s a simple step by step guide on how you can get its resistance.

1. First, you need to check the ohmmeter if it’s working by turning it on and the small screen should display OL.
2. Then set the resistance to x1 but if the ohmmeter has an auto-range capability, you can skip this step.
3. Take the leads and insert them into the ohmmeter.
4. Verify if the ohmmeter is functioning properly by making the lead tips touch each other.
5. The screen should display 1 ohm or sometimes lesser than that.
6. If it reads a higher number, then it is possible that the ohmmeter is not functioning properly.
7. Otherwise, you can proceed with connecting each of the leads to the terminals of the push button switch.
8. Turn on the switch and the ohmmeter should display 1 ohm which means that the switch is turned on.
9. Turn off the switch and the ohm meter will display OL or the resistance of the switch.

Ohmmeter with OL display for normally closed push button switch

49. What is the output signal of a normally closed push button switch?

The typical output signal of a normally closed push button switch is 5 volts or the logic “1”.

50. Is the Stop button a normally closed push button switch?

Yes, the stop button is a normally closed push button switch since it is used to command the operator to stop.

51. Is it safer to use a normally closed push button switch for emergency stop buttons?

Yes, it is safer to use a normally closed push button switch for emergency stop buttons for the reasons below:

1. The operating time is relatively shorter than of the normally open push button switch
2. It has less chance of bouncing back, therefore, provides a better button mechanism
3. When the emergency stop fails the machine stops

It is important to bear in mind that an emergency stop button purpose is to prevent any mechanical or personal accidents to happen.

With the stated reasons above, it is therefore concluded that a normally closed push button switch is a better option for emergency stop buttons.

52. What happens if a normally closed push button stop switch is not wired correctly?

When a normally closed push button switch is not wired properly, typically the machine stops its operation or will not run.

53. What happens when normally closed push button switch’s relay is energized?

When a relay is energized it means that the electrical power supply flows and when it is de-energized, the flow stops or breaks.

54. Do you use a normally closed push button switch on a 3-way switch?

Yes, you can use a normally closed push button switch on a 3-way switch.

A three-way switch has one side of each contact connected.

55. What are the things you need to consider when buying a normally closed push button switch?

When looking for a normally closed push button, there are several things you should consider before making a purchase:

1. Know how it works – Learn the basic functions of the switch to validate what kind are you looking for.
2. What specific purpose do you need it for? – Think about why you need the normally closed button and the functions you want it to operate.
3. Consider the environmental factors – Will you be installing it outside or inside which could help determine the right normally closed push button switch you need.
4. What codes and standards are required in your area? – Check with your building codes or your local standards when it comes to electrical devices to ensure that you don’t violate anything.
5. Consider important specifications – Think about how much amps or voltage you need, or will you need a relay?
6. Other features – Think about the other features you may overlook but are equally important such as the materials used for the switch, color, switch’s design, output terminals and mounting options, the LED color, the backlit design, and so on.

56. Is a normally closed push button switch an affordable option that other switches?

A normally closed push button switch would cost around $1.00 up to $20.00 depending on the type, quality, size, brand, and function.

Where you will be purchasing it may also affect the price.

Other types of switches also have a similar basis for their prices.

The best way is to purchase in bulk to get a better deal.

57. What to look for to check the quality of a normally closed push button switch?

Not many people know that there are markings and symbols you should look for in a push button switch that verifies its high-quality and durability.

Here are some of the quality indicators that you should look for:

1. IP65+ grade

This rating determines how high the level of protection of the enclosures of the switch can provide.

IP stands for Ingress Protection code which is followed by two numerical figures.

The two numbers represent the level of protection it provides against solid and liquid particles.

The higher the number is the better protection it gives.

You can find higher codes such as IP67, IP68, and IP69K.

IP 69K logo

2. IK10

IK is also known as Impact protection.

The number beside it indicates the level of protection the push button switch enclosures can provide against the impacts of kinetic energy.

The highest number is 10.

3. RoHS

This marking is very important to check as it verifies that the materials used to make the normally closed push button switch are safe.

RoHS is the abbreviation of the Restriction of Hazardous Substances which is an international compliance mark.

4. REACH

This is another mark that you should be checking when purchasing push button switches.

It stands for Registration, Evaluation, Authorization, and Restriction of Chemicals.

You can be sure that the product has no potential bad effects on humans.

5. CE

The CE mark assures you that the product offers health, safety, and environmental protection.

These markings and seals are mostly found in high-quality electrical devices and equipment around the world.

With these international quality standards and compliance markings and including the high IP/IK rating, you can be confident that the product is high-quality, durable, long-lasting, and world-class.

You will easily find this information in the product’s packaging, the manufacturer’s website, the product’s description, or their marketing advertisements.

Here’s an example of a push button switch manufacturer that provides world-class standard products encompassing all the seals and markings above.