Safety switches are designed to prevent electrical equipment from being damaged or destroyed due to overloading or short circuits. They are also known as overload relays or trip devices. What are they and why should you consider using them? Should you consider calling an “Electrician near me?”
Safety switches are commonly found in industrial settings where power tools or machinery are connected to live electricity. These devices detect excessive current flow and automatically disconnect power before damage occurs.
Safety switches are often confused with circuit breakers because both terms refer to protective devices. The difference between these two types of devices is that circuit breakers interrupt the flow of electricity whereas safety switches only shut off the electricity supply of power temporarily.
The three main components of a safety switch are:
1) A conductor, which is generally copper wire
2) A bimetallic strip, which will bend when overheated
3) An actuator, which controls whether or not the switch opens and closes based on heat detection.
An example of an open-close type safety switch is shown below.
When the temperature inside the housing rises above 0 degrees Celsius (32°F), the heating element causes the bimetallic strip to bend. This creates a gap between the two halves of the switch. When the strip bends back into place, it closes the circuit again.
A typical circuit breaker has many more moving parts than a safety switch and can be used for much larger loads than a safety switch. However, safety switches are cheaper and easier to install than circuit breakers.
Many people mistakenly believe that all safety switches operate this way. While they work just fine, some types of safety switches have other operating principles. For example, if the heater coil inside the switch malfunctions, it could lead to a false “open” signal.
Safety switches are also available with magnetic reed contacts, mercury-switched contacts, thermal fuses, and electronic devices that operate like microcontrollers.
In most cases, any one of these devices would perform the same function. How do I choose the right kind of safety switch for my application? Read on!
Choosing the right type of Safety Switch
While there are several different kinds of safety switches, each type functions in a slightly different way. Here are a few common types of safety devices:
Open/Close
These types of switches are called open/closed switches. There are two major types of open/closet switches – mechanical and solid state. Mechanical switches use a lever arm that moves within a slot during operation. Solid-state switches rely on a sensor to determine whether or not the contact is closed or opened.
Magnetic Reeds
Magnetic Reed Switches (MRS) were developed as a replacement for traditional mercury-type relays. MRS contains a set of metal strips embedded in a plastic base similar to the shape of a traditional relay. Each metal strip contains several tiny magnets that attract a corresponding magnet on a movable contactor. As the electric contractors move closer together, the amount of force holding them apart decreases until the contactor makes full physical contact.
Mercury Switches
Traditional mercury switches are still very much in demand today. Mercury switches are reliable and cost-effective but do require periodic maintenance to ensure proper functioning.
Thermal Fuses
Thermal fuse switches are designed so that an overload condition will cause electrical resistance to increase enough to heat up a wire inside the device. Once the wire exceeds its critical temperature, the switch opens.
Electronic Devices
Microcontrollers are becoming increasingly popular because they provide better performance at a lower price point. They consist of a small computer chip that monitors various settings of the system being protected. Microcontrollers may feature programmable logic which allows you to create unique and custom solutions.
Where should I install my safety switch?
Safety switches should be located to protect against hazards such as hot wires, live power lines and water. Typically, safety switches are mounted above ground level.
What is an overcurrent device?
An overcurrent device (OCD) is simply another name for an electrical circuit breaker. It’s also known as the main breaker. OCDS typically prevent excessive electricity consumption by shutting off power to a circuit when too much amperage has been drawn through it.
Sometimes an OCD will shut down electricity whenever a safety switch activates. You’ll know your OCD is working properly if no power is present after switching on your circuit.
Can you use one safety switch to protect multiple circuits or items?
Yes! For example, you can have multiple outlets all wired to the same safety switch. This means that every time the switch is activated, all of those outlets turn on. If the switch detects a problem with just one outlet, the others won’t burn out.
How does a circuit breaker work?
A circuit breaker takes a lot of abuse from household appliances and other electrical workloads. When the fuse blows, it’s possible that the part that actually protects the wiring from overheating may fail. The purpose of the circuit breaker is to detect this failing protection mechanism and replace it with a new one before anything bad happens.
This prevents fire and electrocution. A circuit breaker must interrupt current flow through the load. This means that it must open quickly and be able to return to the closed position once the circuit is reestablished.
Why do I need a backup power supply?
The lifeblood of anyone who uses electronic devices is their battery or batteries. If these run out, then the devices become useless. Most people don’t realize how important backup power supplies really are.
Without backup power supplies, most electronic devices would not be compatible with modern society. Luckily, there are many different types of backup power supplies available. There is even a portable type called a hand crank generator.
How can I tell if my safety switch needs replacing?
If you notice any of the following symptoms, chances are your safety switches installed need replacing:
If your safety switch doesn’t feel solid in your hand.
It feels like it could come loose at any moment.
It makes a loud clicking sound when you move it around.
You hear “popping” noises whenever you move the switch.
Your safety switch will look something like this:
Safety Switch Features
When selecting a safety switch, keep in mind that most manufacturers offer additional features that are worth considering. Some common electrical safety switch features include:
Automatic reset
This function keeps the switch from staying stuck in the ON position. Once you remove the load from the line, the safety switch automatically shuts itself off. These switches usually cost more than non-automatic versions.
Double pole
Double pole safety switches allow you to control two separate 120/240V lines. They’re popular in homes and businesses where there are two independent sources of power.
Grounded contacts
Grounded contacts are designed so that they won’t conduct electricity unless the ground wire is connected. This provides extra peace of mind because you don’t need to worry about being shocked by a short circuit.
Indicating LED light
Indicator LEDs tell you whether the switch is turned off or on. When the switch is on, the LEDs glow red. When it’s off, they glow green. Always check to see which colour the indicator lights are flashing before deciding if it’s safe to use the switch.
Low voltage cutout
With low-voltage cutouts, you can disconnect the circuit safely without having to wait for the power to completely shut down. If the main circuit breaker trips, you only have to flick the switch to turn it back on. You don’t have to wait until the entire house is dead.
Overcurrent detection
Overcurrent detection allows your circuit breaker to trip sooner if an appliance overloads. It also helps prevent damage caused by a short circuit. Overload conditions occur when too much current flows through the wires.
Protection against arcing
Arcing occurs when high voltages build up between the hot and neutral sides of a circuit. Because arcing causes serious problems such as melting insulation, overheating, and fire, it’s very dangerous. Many safety switches provide protection against arcing by preventing the flow of excessive currents.
Reset button
When you push the reset button, the safety switch resets itself so it does its job again. Resetting the switch may be necessary if you accidentally leave loads attached while switching off.
Self-testing function
If you aren’t sure whether the safety switch is working properly, you can test it yourself with a multimeter. By measuring the resistance across the terminals, you can determine whether the contacts inside the switch are making good contact.
Smoke detectors
If your smoke detector goes off every time someone smokes a cigarette, it’s probably time to replace it. Smoke alarm sensors make it easier to protect yourself and others from fire hazards.
Spark arresters
A spark arrester protects electrical components like transformers and motors from sparks that could start fires. The device should always be placed at least 10 feet away from any electrical component.
Stainless steel housing
Safety switches made of stainless steel are both corrosion-resistant and easy to clean.
Test button
You can easily test the integrity of a safety switch using a multimeter. Simply measure the resistance between the terminals and compare the results to factory specifications (which you can find online).
Trip latch
A trip latch prevents the switch from turning back on after it’s tripped. Trip latches help ensure that it doesn’t take more than one attempt to break the circuit.
Waterproof design
Most safety switches feature waterproof housings that allow them to withstand all kinds of weather conditions. They’re especially useful during floods and other natural disasters.
In case you are looking for a local electrician for electrical emergencies, you can search online for “Electrician near me”, a “licensed electrician” and “emergency electricians” or simply call us. We are 24 hours available and we will send out our professional team to do the best service to meet your needs.
