Electricians and other buyers can choose from a range of different types of isolator switch devices. These range from simple 1-pole isolator switch for lower voltage systems to the complex 4-pole isolator designs for higher, voltage 3-phase systems. Before diving deep into their different types, let’s understand what isolator switches are.
Isolator Switch Meaning
An isolator switch is defined as an electrical safety device that, when used in power systems, helps to separate a circuit from the power supply. This allows for maintenance and fault finding –and all without affecting the other parts of the system.
When fused, an isolating switch also minimizes potential shock hazards from live conductors and damage to equipment by blowing the fuse in a condition of overcurrent. Generally, these switches feature two positions – on or off.
Because electrical systems are not one-size fits all, there are different types of isolator switch options. Each one is suited to a different application and system and users must select the device that is compatible with their unique needs.
Types of Isolator Switch
Different types of isolator switch devices are differentiated by various factors, such as the type of power source they support, number of poles, if they’re fused or not, and more. In view of that, here are the nine types of isolator switching devices available:
1. AC Isolator Switch
AC means alternating current and one of the two well-known electrical systems. In an AC system, electricity changes its direction periodically. It also uses single or three phase power distribution to supply power to different circuits.
Therefore, an AC isolator switch is designed to ensure that each circuit in this type of system can be safely isolated from the power supply when needed. These types of isolator switch devices are most common in systems that connect to the grid.
2. DC Isolator Switch
A DC isolator switch is designed for use with DC electrical systems. These include solar and battery-based systems. This type of isolator switch is used to disconnect a DC system from its power supply, and can be one of the following array isolator or battery isolator:
A DC isolator switch for solar panels or isolator switch for solar battery is adequately rated for DC. Because DC circuits arcing can be difficult to contain, these types of solar disconnecting switches are typically rated at 20% higher than the current of the circuit.
3. Fused Isolator Switch
These types of isolator switch include a fuse or fuses in their boxes or enclosures. The isolator switch fuse serves as an additional layer of protection for the circuit, especially in applications that require extra protection due to overcurrents.
In an event that the disconnected circuit still draws current, the fuse will disconnect it from the system, by blowing. A fused isolator switch is typically used in circuits that experience higher amounts of currents and surge, as already mentioned.
4. Non-Fused Isolator Switch
This is an isolation switch that does not incorporate a fuse. Compared to the fused types, the non-fused isolator offers less protection. However, that does not make it less effective since their application is also different:
Non-fused isolator switch types are designed to protect low power circuits from the power supply, typically those that experience lower fault current magnitudes. These are low-risk circuits such as those for lighting systems, – or if the circuits are adequately fused upstream.
5. 1-Pole Isolator Switch
The 1-pole isolator switch is designed for single phase systems. It often comes as a non-fused version and with a rotary actuator, depending on the application requirements. The single pole isolator switch, as the 1- pole isolator is also called, is normally used in lower power circuits.
6. 2-Pole Isolator Switch
The 2-pole isolator switch is used in a single phase electrical system. It has two poles to ensure the power supply of each phase can be isolated individually. This type of isolation switch offers more protection and safety than the single pole switch as it disconnects all phases simultaneously.
7. 3-Pole Isolator Switch
The 3-pole isolator switch is designed for three phase AC systems and is the most common type of isolation switch used in those applications. In addition to being able to disconnect 3 circuits independently, this type also allows for the simultaneous disconnection of all three circuits, and is also often called a 3-phase isolator switch.
8. 4-Pole Isolator Switch
A 4-pole isolator switch is similar to the 3-pole but with an additional dedicated pole for neutral. This fourth pole helps to ensure that the neutral wire is completely disconnected from the circuit when the switch is in the off position.
This type of isolator switch is commonly used in commercial or industrial applications that require higher levels of safety and protection. Usually, it’s a fused isolator that will also offer protection against short-circuits and other faults via the fuse.
9. 6-Pole Isolator Switch
Also available is the 6-pole isolator switch. These types of isolator switch are generally used for very high-current applications in three phase AC systems. Just like the 2, 3, and 4-pole isolator, the 6-pole isolator switch isolates electrical systems, but at a higher rating.
These isolator types are, therefore, used in higher voltage and complex applications, such as those found in manufacturing plants and similar settings. The 6-pole isolator switch is will normally be available in fused versions.
Other Types of Isolator Switch
Isolator switches area also distinguished by their mounting methods, such as the base mounted isolator switch, the flange mounted switch, panel mount switch, or DIN rail mounted isolator switch.
There are also types of isolators based on their IP enclosure ratings –which refer to their degree of protection against dust and water ingress. For example, an IP65 isolator switch is suitable for outdoor applications and offers a higher degree of protection against elements such as rain and snow.
Depending on where you want to use the switch, there are nine main types of isolator switch variations that you can select from today. Therefore, electricians and other buyers must be familiar with what these different types of the device are and how to suitably apply them. This, in addition to the safety regulations and codes, will help them make the right decisions when it comes to selecting a switch for their specific isolation needs.