Lighting Contactor Wiring Diagram With Photocell? Best 191 Answer

Our guide has everything you need to know about contactors, including how they work and how to use them.

This introductory guide to shooters aims to provide clear and comprehensive answers to frequently asked questions about shooters. We will take a quick look at how electrical contactors work, how they are used and what types are sold online in the UK. We’ll also cover some of the most popular types and brands of shooters available and how to choose the best for your needs. Search all shooters

What is a contactor? A contactor is an electrical device commonly used to switch circuits on and off. As such, electrical contactors form a subcategory of electromagnetic switches known as relays. A relay is an electrically operated switching device that uses an electromagnetic coil to open and close a series of contacts. This action results in a circuit being either switched on or off (the circuit being made or broken). A contactor is a specific type of relay, although there are some important differences between a relay and a contactor. Contactors are primarily designed for use in applications where large amounts of current need to be switched. If you’re looking for a concise definition of electrical contactors, you might say something like this: A contactor is an electrically controlled switching device designed to repeatedly open and close an electrical circuit. Contactors are typically used for higher current applications than standard relays, which perform a similar task of lower current switching.

What are contactors used for? An electrical contactor is used in a variety of situations where power must be repeatedly switched to a circuit. Like relay switches, they are designed and built to perform this task over many thousands of cycles. Contactors are primarily chosen for higher power applications than relays. This is due to their ability to allow low voltages and currents to switch on and off a far higher voltage/current circuit. Typically, a contactor is used in situations where power loads need to be switched on and off frequently or quickly. However, they can also be configured to either turn on a circuit when activated (normally open or NO contacts), or turn off power to a circuit when activated (normally closed or NC contacts). The two classic applications for a contactor are as an electric motor starter – such as those used in auxiliary contacts and connectors used in electric vehicles – and in high power lighting control systems. Typically, when a contactor is used as a magnetic starter for an electric motor, it also offers a number of other safety features such as current cut-off, short circuit protection, overload protection and under voltage protection.

Contactors used to control high power lighting systems are often placed in an interlocking configuration to reduce overall power consumption. This arrangement involves two electromagnetic coils working in tandem. A coil closes the circuit contacts when briefly energized and magnetically holds them closed. The second coil opens them again when energized. This type of setup is particularly common in automating large office, commercial and industrial lighting installations. The principle is similar to how a latching relay works, although the latter is more commonly used in smaller circuits with reduced loads. Since contactors are specifically designed for this type of high voltage application, they are typically physically larger and more robust than standard relay switching devices. However, most electrical contactors are still designed to be easily portable and mountable and are generally considered very suitable for use in the field.

How do Sagittarius work? To better understand how a contactor works, it is helpful to know the three core components of an electrical contactor when assembled. These are usually the coil, contacts and device body. The coil or electromagnet is the key component of a contactor. Depending on how the device is set up, it will perform a specific action on the switch contacts (open or close) when power is applied

The contacts are the components of the device that carry current across the circuit to be switched. There are several types of contacts in most contactors, including spring and power contacts. Each type fulfills a specific function in the transmission of current and voltage

The contactor housing is another important part of the device. This is the housing that surrounds the coil and contacts and helps insulate the key components of the contactor. The housing protects users from accidentally touching conductive parts of the switch and provides robust protection against risks such as overheating, explosion and environmental hazards such as dirt and moisture. The principle of operation of an electrical contactor is straightforward. When current flows through the electromagnetic coil, a magnetic field is created. This causes the armature to move in a certain way within the contactor in relation to the electrical contacts. Depending on how the specific device was designed and what role it is intended for, this will usually be the opening or closing of the contacts. If the contactor is normally open (NO), energizing the coil with voltage will force the contacts together, making the circuit and allowing current to flow through the circuit. When the coil is de-energized, the contacts are open and the circuit is off. This is how most shooters are set up

A normally closed (NC) contactor works in reverse. The circuit is closed (contacts closed) while the contactor is de-energized, but open (contacts open) when the electromagnet is energized. This is a less common configuration for contactors, although it is a fairly common alternative configuration for standard relay switches. Contactors can perform this switching task rapidly over many thousands (or even millions) of cycles over their lifetime.

Contactor Wiring Diagram A general example of a contactor wiring diagram might look something like this. This example diagram would be for a three pole contactor with an N.O. base contact.

The Difference Between Contactor and Relay Although we have already established that contactors are used for higher power applications than relays, understanding the full technical differences between contactor and relay is a bit more complex. A more complete list of the differences between a contactor and a relay would include: Rating. Contactors are designed and built to handle much higher performance switching applications than control relays. Relays are typically reserved for use with loads of around 5A to 15A, and they are most often rated at 10A or less

contact norms . Contactors are almost always set up in a normally open (NO) configuration. This means that the circuit is only made while the electromagnet in the contactor is receiving power. Relays are easy to find with both normally open and normally closed contacts

protection and security features. Contactors typically offer a much wider range of safety cutouts and protections, reflecting the fact that they are designed for higher power applications. In fact, a specific type of switch known as a contactor overload relay is specifically designed to prevent machines and circuits from overheating. Common examples of standard contactor safety features include: Spring loaded contacts to break a circuit when the contactor is off

Overload protection that intervenes when the circuit receives a surge of current for a defined period of time

Magnetic arc suppression, which forces current arcs to travel a greater distance than the energy they transfer can withstand. Because contactors are designed for high-power, higher-power applications, they are typically physically larger and heavier than relays, and their switching speed is significant as well slower. They are also more expensive than relays in most cases and draw more power due to their larger electromagnetic coils.

Contactor Selection Guide Many different types of contactors can be bought online in the UK and elsewhere including single phase contactors and three phase contactors. Selecting the best electrical contactor for a specific application requires careful evaluation of several key metrics, features and specifications. Load requirements and power ratings (voltage and current) are always among the most important considerations.

Types of Contactors Magnetic Contactor A magnetic switch contactor operates entirely via electromagnetism and therefore does not require direct intervention to consistently perform its role. This makes it one of the more efficient and reliable designs as the electromagnetic switching only requires a small amount of energy. It also allows full remote operation of the contactor. Almost all electrical contactors work on this basis today. Switch Ratings and Coil Ratings (Contact Voltage and Current) Contactor switch ratings are typically reported as two separate metrics – Maximum Switching Voltage and Maximum Switching Current. The upper limits of voltage and current that a switch design, make or model can handle must always be evaluated directly against the requirements for the circuit or motor in which it is used. While a product may be listed as a 230V contactor, 240V contactor, or 1000V DC contactor, more detailed manufacturer specifications usually relate directly to a device’s maximum coil voltage, contact current, contact voltage, and total rating. They also list the number of auxiliary contacts, terminal type, normal state configuration, and minimum and maximum operating temperatures. Contactors generate more heat than relays, which must be taken into account when choosing a suitable unit for the installation. Different electrical ratings for contactors are often given as either resistive or inductive, depending on the intended use of the module. Resistive ratings are more common for contactors used with heating elements or lighting control equipment, while inductive load ratings are more common for motors, transformers, and solenoids. It should also be noted that the contactor coil voltage (control circuit voltage) does not necessarily have to match the load voltage to be switched on and off. For example, the coil voltage could be 24 VDC, but the motor being cycled on and off could be 400 VAC. Typical coil voltages available include 12, 24, 48, 110, 230, and 400V.

Contactor Brands Many leading brands are known for producing high quality, reliable electrical contactor switches. Some of the most sought after suppliers we work with to supply our extensive range of switches and contactor accessories include ABB, Allen Bradley, Eaton, Lovato, Schneider Electric, Siemens, TE Connectivity and WEG.

In all control circuits and automation systems, logic is developed based on the open or closed state of switches, sensors or relays. Therefore, it is imperative to understand the concept behind NO/NC. Normally open (NO) and normally closed (NC) are terms used to define the states of a switch, sensor or relay contact when its coil is not energized. It is the basis of process automation.

What is NO contact?

A normally open or normally open is the one that stays open until a certain condition is met. For example, consider a limit switch. A limit switch consists of at least one make contact. The normally open contact in the limit switch remains open until its actuator is pressed. When the actuator is pressed, the contact closes and begins conducting. With proximity switches, the normally open contacts remain open until an object is detected. Similar to pressure switches, the contact remains open until the preset pressure level is reached.

The picture above shows the states of the NO contact of a push button in the normal state and in the pressed state.

What is opener?

A normally closed or normally closed contact is functionally the exact opposite of a closer. It remains closed until a certain condition is met. In this case, let’s consider the operation of the limit switch. A limit switch’s NC contact, when used in a circuit, breaks the circuit or current flow when its actuator is depressed. Likewise, a relay’s contacts remain closed unless its coil is energized.

Normally Open Contacts Normally Closed Contacts Remains open until a specified condition is met. Remains closed until a certain condition is met.

The image above shows the NO and NC arrangement of a limit switch (Click to enlarge the image). Contacts 1 and 2 are normally closed, ie they remain conductive until the actuator is pressed. When the actuator is pressed, it stops the conductor. Contacts 3 and 4 are make contacts, i. H. they start conducting when the actuator is pressed.

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Ever wondered how streetlights seem to know when to turn on? They’re never too early or too late…they light up just as the sun goes down and the sky turns black.

Of course, they are not operated manually. But surely they don’t work on a timer either, since they turn on and off at slightly different times each day?

The answer is photocells, also called twilight sensors.

The basic principle behind photocells has been around for more than a millennium, so does it work with modern LED lights?

Standard photocells require a small current to function during the day when the lights are off. Because LEDs operate at such a low voltage, this small current causes interference, flickering, and premature degradation. As a result, LEDs require a different type of photocell than traditional incandescent bulbs.

If you come home from work in the evening and like to leave the lights on, then this blog post is for you.

Just because you use LED bulbs doesn’t mean you have to forego the convenience of twilight sensors.

Read on to find out everything you need to know!

What is photocell?

Photocells, twilight sensors, light dependent resistors, whatever you call them, they all do the same thing.

Photocells are light-sensitive modules used to determine the on/off status of the lights based on the ambient light level. Simply put, they are light detectors that automatically turn lights on at dusk and off at dawn.

They are most commonly found outdoors in park, roadway, and security lighting.

They are a great way to reduce energy consumption as they are designed to turn off lights during the day when artificial lighting is not required.

But how do they work?

There are countless different photocells on the market, but they are all based on the same principle. Similar to LEDs, photocells are made of semiconductors, primarily cadmium sulfide.

They are designed to respond to visible light. When the semiconductor is exposed to a certain level of light, an electric current is generated and the lamp is switched off.

But when the sun goes down and the light level decreases, the electric current stops and the lamp is switched on again.

As far as makes sense?

Alright, let’s dive a little deeper then.

Photocells are essentially a daughter of the photoconductive effect, which is the idea that electricity can be generated with a beam of light. This principle was first discovered by Heinrich Hertz in 1887.

Photocells work because when they are not near a light, they have a high electrical resistance of about 20 million Ω (ohms). Electrical resistance is a measure of resistance to the flow of electricity.

High resistance means that the electrical current flow is completely rejected by the photocell, allowing the LED to perform at its full potential.

In daylight, on the other hand, the photocell has a low resistance of around 100 Ω. The sensor buzzes with electricity, but the start-initiator of the LED lamp does not get anything and prevents it from turning on.

In general, there are two main types of photocells. With pluggable light barriers, the sensor is located within the occupied space, i.e. the light bulb.

With line voltage photocells, the sensor is part of a larger circuit of devices and is likely to be in a different location than the lightbulb itself.

Are LEDs compatible with Dusk To Dawn sensors?

Let’s get the facts straight.

When photocells were first invented several decades ago, they were specifically designed to work with tungsten (incandescent and halogen) and ballasted (fluorescent and HID) bulbs.

It wasn’t until LEDs became popular in the early 2000s that people realized that traditional photocells are incompatible with CFLs.

Because of the way they work, photoelectric sensors generate a small amount of electricity during the day when the lights are off.

Conventional light bulbs operate at high voltages, so this small current has no effect and the light stays off.

However, LEDs require much less power, so this small current causes noise and acts as a capacitive load.

Ultimately, this leakage voltage damages the electronics in the LED. When paired with a traditional photocell, the LED is likely to behave erratically, flickering on and off, or burning out prematurely.

Luckily, lamp manufacturers soon caught up and developed a photocell system that directs the small current away from the LED.

In summary, old twilight sensors will probably not be compatible with LEDs, but newer models will be more flexible.

Can LED lights with incompatible photocell flicker?

If you’ve been paying attention, you already know the answer to this question.

But to reiterate, yes, LED lights will flicker when paired with incompatible photocells.

This is because the low current of the photocell interferes with the LED.

But there are also several other reasons why your LED lights can flicker from dusk to dawn.

I’ve seen many people complain about their lights flickering at dusk before sunrise and sunset. This is when the lights are about to turn on or off.

Unfortunately, there’s not much you can do about it. If your photocells are adjustable, you could try playing with the light parameters needed to trigger the lights.

But as soon as it gets very dark or very light, the flickering stops by itself.

Another thing worth noting is that photocells are triggered by any light source – be it natural, artificial or reflected.

As your photo sensor picks up its own light, it may start flicking on and off. The easiest way to counteract this is to cover the light barrier so that only natural daylight can reach it.

How to choose photocell sensors for outdoor LED lighting

As you can see, selecting an LED compatible photoelectric sensor is no easy task.

You can’t just go to your local hardware store and buy the first one you can get your hands on, it requires an informed purchase.

So what things do you need to watch out for?

First things first, you need to ensure that the sensor utilizes modern photocell technology designed explicitly for LEDs.

You can verify this by reading the sensor’s product data sheet. This is usually listed in the Rated Load section.

Regardless of the type, photoelectric sensors have three wires. In some cases the extra cable may be present when the photocell is supplied with the timer.

Then you need to check that the voltage of the photocell matches the installation voltage of the LED. For example, this 120 volt photocell from Amazon needs to be paired with a 120 volt LED bulb.

last words

That’s a wrap! That’s all you need to know about photocells and their relationship to LEDs.

You no longer have to worry about tripping over your garden ornaments when you come home after a night out with friends.

I suspect that the traditional photocell design will be phased out in the coming years, in line with the decline of incandescent and halogen bulbs.

Did you know the science behind photocells? Will you buy a twilight sensor for your LED lights? It would be great to hear from you, leave a comment below.

Q: I plan to buy 18 bollard lights soon to light a path. I want them to turn on automatically at night. Do I also have to buy 18 light barriers?

On a. You only need a light barrier.

A photocell is a device that works like an electrical switch. When the photocell detects ambient light, the photocell turns off the lights controlled by the photocell. If the photocell does not detect any ambient light, it turns on the same lights. A photocell can control multiple lights provided they are on the same line, just like a manual switch can turn multiple lights on and off.

Photocells are designed to prevent someone from having to go outside and manually turn on the outside lights every time it gets dark. They are also more efficient than timers that turn lights on and off at a specific time of day. Timer clocks do not take into account the changing light levels associated with seasonal changes and daylight savings time, but photocells do.

So why shouldn’t it make sense to buy 18 photocells? Because only one photocell is needed to control a group of lights connected to a single power source. Here’s how.

Sufficient current is supplied from a line to a switch that turns the current on and off. The power line continues to a switch box mounted in a location that can see natural light but no illumination from fixtures. The current is routed to a photocell mounted in the electrical box. The light barrier acts as a second switch. When power is on at the first switch, the photocell controls the power from the switch box. The power line then continues to each of the 18 bollard lights to power the bollard lights. When the first switch is on, the photocell senses when it’s getting dark and turns on all the bollard lights. The use of a photocell guarantees that all LED devices are switched on and off at the same time.

Photocells are a highly efficient option to turn outdoor lights on and off. Certain types of photocells work better on some products than others, which is usually left to an electrician’s discretion. The photocell shown in the image above is a typical photocell that works well for many applications. Photocells can be purchased from Access Fixtures when purchasing bollard lights. If you have any further questions, please contact an Access Fixtures lighting specialist.

Wiring a photocell for an outdoor light

How to wire a photocell control to an outdoor light: Matching a photocell to an outdoor light, an example of wiring a 120 volt photocell to control the light.

Electrical Video #1 Electrical wiring and electrical repairs made easy? We’ll help you wire it right! See more home electrical wiring videos Watch and subscribe to my YouTube channel! Watch electrical wiring video #2 below:

How to wire a photocell

Electrical Question #1: I want to control an outdoor light with a photocell. How can this happen?

Wiring a 1000 watt outdoor light

The light is now wired for 240 volts and wants to turn it on and off with a photocell. I have a photocell and was just wondering if you only switch one leg to turn it on and off and if that is the case why is a 240 volt photocell needed? Each leg is 120 volts just looking for some understanding.

This electrical question came from: Joe in Michigan.

Electrical Question #2:

I have a 3 wire outdoor power cord along with an AC-DC transformer (in. AC 100 240V, 125W), a photocell (120V, 4.2 amp, 500W, 7.1A, ballast) with a red wire, one white wire and one black wire. There are 4 12 volt landscape lights with 1 blue and 1 brown wire.

I have the red wire from the photocell to the brown wire on the headlight. The black wire from the photocell to the black wire from the house circuit. All wires white on white, and the blue wire. The light doesn’t go out.

This electrical wiring question came from John in Florida.

Dave’s answer:

Thank you for your electrical wiring questions.

Light barrier control for outdoor lighting

Application: How to wire a photocell to control an outdoor light.

Difficulty Level: Intermediate to Advanced. This electrical installation project is best performed by a licensed electrical contractor or a certified electrician.

Tools Required: Basic Electricians Pouch hand tools and voltage tester.

Estimated Time: Depends on personal experience and ability to work with tools.

Precaution: Before working on the timer wiring, identify the lighting circuit, turn it OFF, and label it with a note.

Note: Installation of additional luminaire wiring should be approved and verified in accordance with local and national electrical codes.

Materials: Ensure the timer has the same amperage and voltage as the original switch and is fully compatible with the circuit, fixture and type of lightbulb being used.

Wiring a photocell to control an outdoor light

Matching the photocell to an outdoor light

There are applications where a 240 volt load can be switched on and off with just one branch circuit, but I wouldn’t advise it unless it’s a built in control circuit of the device.

The photocell used to control your 1000 watt outdoor light requires 240 volts to operate the photocell and since the 240 volt circuit does not have a neutral wire you cannot use a 120 volt photocell which requires a neutral wire.

The solution is to get a photocell that matches the voltage configuration you wired the outdoor light for and wire it according to the diagram.

Photocells are available for most voltages and various wattage or circuit load requirements.

Light barrier basics: How a light barrier works

A photocell is basically an automatic switch that is controlled by sunlight during the day and darkness at night. The change from light to dark automatically activates the photocell to switch on the lights connected to it.

Example of wiring a 120 volt photocell

The circuit and line wiring connections

A typical photoelectric switch requires circuit wiring that includes the green ground wire, white neutral, and black circuit wire.

A typical photoelectric switch requires circuit wiring that includes the green ground wire, white neutral, and black circuit wire. The load wiring connection

Photocell load wiring is usually where the black wire going to the light connects to the photocell red wire.

Photocell load wiring is usually where the black wire going to the light connects to the photocell red wire. Remaining light wires

The white neutral and ground of the lamp are connected to the white neutral and ground of the photocell.

See more about electrical wiring for outdoor lights

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A complete listing of electrical wire types and parts used in home projects, with electrical code information, serves as a selection guide.

More information on the 220 volt wiring diagram

220 volt wiring diagram

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House electrical wiring includes 110 volt outlets and 220 volt outlets and outlets common in every home. See how outlets are wired for the home.

Now you might be wondering why do we need to use a contactor? Can’t we connect the motor directly to the PLC? Well, the short answer is no.

Why? Because you don’t want to connect a high-voltage electric motor directly to your high-priced PLC. This will damage the PLC boards when electrical surges occur on the motor side.

Instead we use a contactor to indirectly and safely connect the PLC to the motor. What do we mean by indirect you ask? Well, all contactors have a low voltage coil. We connect the PLC output to this coil. This coil normally operates on a 24 volt DC signal.

As soon as the coil is energized, an electromagnetic field is generated. This electromagnetic field then causes the three contacts here to close, allowing the 3-phase current to reach the motor and turn it on. Looks like magic, right?

Lighting contactors are relay switches that control the flow of current through a circuit that supplies lighting in a specific area. They exist remotely and control higher voltage circuits that can be dangerous to the operator if controlled directly. A light contactor switch operates on a lower but safer load and controls the high voltage/current circuit with an electromagnet.

Turn off the power for the entire system. Turn it off using the system circuit breaker. Wear electrical gloves and take other safety precautions necessary to avoid accidents since lighting circuits work under heavy electrical loads.

Locate and open the service box that passes power to the lights. This box is usually mounted in a spot near the lights and contains a transformer and wires connecting the lights to their switches and the circuit breaker. Mount and screw the contactor into the service box using a screwdriver.

Use a screwdriver to loosen the terminal screws on the mounted contactor. There are a total of six terminals on lighting contactors; two for low voltage and four for high voltage. The low voltage terminals are also referred to as “control”, the high voltage output as “load” and the high voltage input as “line”.

Connect the wire from the switch to one of the low voltage terminals on the transformer. Connect another wire from the second low voltage terminal of the transformer to one of the control terminals of the contactor. Take the second wire from the switch and insert it into the second control slot on the contactor.

Plug the neutral wire from the circuit breaker and one of the high voltage wires on the transformers into the contactor wire terminal labeled “L1”. Connect the live/hot wire from the circuit breaker and the other high voltage wire at the transformer to the line terminal labeled “L2”. The live wire is either black or red, while the neutral wire is white.

Connect the neutral wire going to the lights to the load terminal marked “L1” and the live/hot wire to the terminal marked “L2” on the contactor. Close the service box after all connections are properly made.