< img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=363518808911477&ev=PageView&noscript=1" />

Voltage Protector vs. Surge Protector: 5 Key Differences

Voltage protector vs. surge protector: what is the difference? While both are protection devices, several things set them apart. This article compares the two products, highlighting their varying features. We will also be seeing situations that require voltage protection and those that need surge protection.

What is a Voltage Protector?

A voltage protector is an electrical device that shields a power system or appliance from the damaging effects of voltage fluctuations, including over and under-voltage.

Energy sources, especially the grid, are prone to disruptions. These come in the form of voltage levels that are either too high or too low. Such variations can harm sensitive circuits and electrical appliances.

A voltage protection device connects to the supply in series and monitors the voltage; if it goes too high or too low, it shuts down the energy flow. It then restores power later when the voltage returns to normal.

What is a Surge Protector?

A surge protector is a device that can absorb sudden and short-lived voltage spikes. It specifically guards a power system or appliance against damage by redirecting the resulting current to the ground.

A surge is a sudden increase in voltage that occurs momentarily, within a millionth of a second, but which can cause severe damage to power systems and connected loads.

Various occurrences cause transient pulses, including lightning strikes and load shedding, or when heavy-duty loads switch on or shut off.

A surge suppressor or protector short-circuits the excess energy to ground, using components whose resistance is high in standard voltage and low in a spike or higher voltage pulse.

Surge Protector
Adjustable voltage protectors for over-voltage and under-voltage protection
Resource: https://youtu.be/O4WzABoi4gs?

Voltage Protector vs. Surge Protector

With both serving as power protection devices, how are surge and voltage protecting devices different? This section compares them on these fronts: design, function, working, rating, and specific uses or applications.


A surge protector for a power system protection is roughly the size of conventional electrical panel protection devices, with terminals on the upper and lower side for the various wire connections.

The scaled-down version (for appliance protection) is where design variations begin to show. The types of surge protection devices in this class range from plug-in protectors to insert into outlets to power strips and standalone gadgets.

The voltage protector has limited design variations. It’s typically a compact device the size of the usual service or distribution panel devices, with a digital screen and button adjustments on the front to set voltage levels.

Voltage Protector vs. Surge Protector


A voltage regulator protects delicate circuits from voltage levels that are too high or too low. It constantly monitors the voltage and shuts the supply if it detects a change. That way, the device prevents power fluctuations from causing damage instantly or over time.

The primary purpose of surge protectors is just that: surge protection. It shields your power system or electrical appliances from excessive voltages caused by lightning bolts and other causes of grid disturbance.


Voltage protection devices use a combination of electronic components to safeguard electrical equipment and systems. They cut off power if they detect a variation in the amount of voltage. Surge current protectors do not cut off supply. Instead, they direct the excess energy to the ground.

Some types of surge protectors may use metal oxide varistors, or MOVs in short, to safeguard circuits or discharge tubes. Others use breakdown diodes. Most surge protection devices in use today are MOV-based. Here is how they work:

  • When the voltage is as expected, the MOV resistance is high.
  • The current then flows in the required circuits to power loads.
  • In a sudden overvoltage, the MOV becomes a conductor.
  • The excessive current now momentarily flows through the MOV to the ground.
  • When the voltage returns to normal, the MOV becomes a resistor again.
  • The gas-discharge tube and diode types work similarly.


Both voltage and surge protection devices are widely rated, depending on their specified uses. However, the surge protection type generally has a higher rating than a voltage protector.

Transient surges can be much higher than the standard grid voltage, sometimes up to several thousand volts. Surge protection equipment must be able to withstand that.

On the other hand, an under or overvoltage protector is built to handle fluctuations and is typically rated lower. That said, it’s good to note that ratings vary widely across each protector.


Surge diverters are commonly installed in the service entry point to protect the entire power system. You may also place them in the subpanels to protect branch circuits or the upstream of an electrical appliance.

Voltage protectors are typically system and appliance protection devices. They safeguard sensitive electrical and electronic products such as TVs, computers, refrigerators, etc. 

Surge protector for home power system
Surge protector for home power system
Resource: https://www.youtube.com/watch?v=f4iYfrLfzsA

Voltage Protector or Surge Protector: When to Use

Knowing when and where to use either device can be confusing, given their similar purposes in an energy system. Now that we have seen their differences, here’s more about the application of each piece of electrical equipment.

When Do You Need a Voltage Protector?

A voltage protector is used in homes to protect electronics and electrical appliances. In offices and commercial buildings, they shield various gadgets against voltage fluctuations.

Use them if your region experiences frequent grid disturbances that can see the voltage go up or down to unsafe levels. You also need these if your area is prone to surges caused by thunderstorms or other sources.

When Do You Need a Surge Protector?

Surge protectors are mainly used to offer entire line protection. They conduct transient surges to the ground and withstand high voltages and currents.

Use these if your place is susceptible to lightning strikes or the grid outages are common and other disruptions. If you live near a large manufacturing plant, you need one, as power surges will likely be regular.


Surge and voltage protectors both shield your power system components, including appliances, from getting damaged by grid disturbances. But while that is so, the two devices differ in several ways. When using either product, ensure you understand these variations, including the specific applications in a power system.

Table of Contents

Request A Free Quote