Electricity helps run various devices such as computers, lights, refrigerators and air conditioners. However, with every advantage, there are some drawbacks too, and in this case, power surges are a menace. They are spikes in voltage and can destroy electronic equipment within moments. This is where a surge protection device (SPD) can come in handy.

While it does not matter whether it is a home, office or an industrial facility, an SPD can always be installed to help save valuable electronics and appliances from electrical surges. But the questions arise, what is a surge protection device, how does it function and what are its types? Let’s try to answer these questions in the simplest way possible.

What is a Surge Protection Device?

A surge protection device (SPD) is an electrical component that protects electrical devices from either voltage spikes or surges. In essence, it surrounds the devices and the electrical supply, acting as a shield.

Lightening hits, power grid fluctuations, turning on heavy machines, etc., can all potentially lead to sudden increases in voltage. SPDs are able to protect devices with ease under such situations as they detect the surge in volts and reroute the excess charge to ground to prevent it from damaging the appliances.

To put it simply, a surge protection device works just like a pressure relief valve works for plumbing, but this would be for your electrical system. Like it sounds, it can “absorb the shock” and your devices are safely protected.

Importance of Having A Surge Protection Device for Home

An average modern home is filled with devices such as: smart TVs, refrigerators, washing machines, laptops, internet routers, and even smart lighting systems. Each one of these devices have their own varying degrees of sensitivity towards voltage fluctuations.

A surge protection device for home acts as the first line of defense a homeowner would need offering:

• Protection from lightning strikes

  Lightning strikes can create powerful surges that damage household appliances and wiring. A surge protection device for home channels this excess energy safely into the ground. It prevents electrical fires and equipment failure. It’s especially crucial in areas prone to thunderstorms or where lightning protection is a regulatory requirement.

• Safety during utility switching

  Power companies may switch between transmission lines or transformers for maintenance or rerouting. These actions often cause voltage spikes. A surge protection device stabilizes the electrical current during such utility switching events. It ensures that delicate electronics like computers and TVs are not exposed to unsafe voltage levels.

• Defense against surges caused by heavy appliances cycling on/off 

  Heavy-duty home appliances like air conditioners, washing machines, and refrigerators generate internal power surges when cycling on and off. These frequent fluctuations can degrade smaller devices over time. Surge protectors help absorb and smooth out these sudden voltage shifts. They extend the lifespan of connected electronics and home appliances.

  Surge protection devices are important, as with today’s electronics even a surge lasting less than a millisecond can damage sensitive circuit boards or significantly shorten the lifespan of your electronics.

Surge Protection Device Working Principle

Let’s discuss something a little bit less complicated than how surge protection device works.

A surge protection device working principle is affected while detecting abnormal voltage, excess energy, and safely diverting that energy from the devices.

For a clearer understanding, this is what occurs:

• Voltage spike occurs (lightning, restoration of power, etc.). This sudden increase in voltage is often unpredictable and can last only microseconds. But, it’s strong enough to damage or destroy electronics. Lightning strikes, power outages, or grid switching can all cause these voltage spikes. This makes surge protection critical for uninterrupted electrical safety at home.

• SPD detects the surge. Surge suppressor activation occurs when voltage exceeds the tolerable threshold. The SPD continuously monitors voltage levels in real time. When it senses that voltage exceeds the safe threshold, typically above 230V in homes, it quickly activates internal components like metal oxide varistors (MOVs) to begin suppressing the excess voltage and shielding connected devices from harm.

• Sensitive equipment no longer gathers excess energy, while directing the excess energy gives a low resistance pathway to ground away from sensitive equipment. This redirection of excess voltage prevents damage to devices like TVs, laptops, and kitchen appliances. The SPD offers a preferred route, low impedance path, for the surge to flow harmlessly into the ground, sparing delicate internal circuits from being exposed to the harmful spike.

• The SPD reverts back to standby mode, monitoring status, as voltage normalizes and SPD deactivates. Once the surge has passed and voltage stabilizes, the SPD stops conducting and returns to a passive state. It resumes monitoring for future spikes, ready to activate again instantly. This cycle allows the SPD to offer round-the-clock protection with minimal maintenance or user intervention.

Critical components of most SPDs contain Metal Oxide Varistor (MOV) which has a variable resistance. At default voltage, the MOV is exhibiting high resistance, but during a spike, reactive current's path-to-ground, reduces resistive forces offered by MOV.

Types of Surge Protection Devices

For SPDs, there is no single universally applicable remedy. Based on your area of interest or the degree of impact sustain, varying options are available.

1. Type 1 SPD -

• Located before the main circuit breaker at the principal electrical panel.

• Created to withstand lightning strikes and external surges coming from power-line cables.

• Commonly found in structures fitted with lightning protection systems.

• More appropriate for Industrial or commercial system use.

2. Type 2 SPD -

• Situated after the main breaker but before sensitive equipment.

• Protects from Type 1 surges and internally generated surges.

• Standard representative for residential and commercial buildings.

• Most suited to shield other common household devices and appliances.

3. Type 3 SPD -

• These are typically put into use at wall sockets and come in the form of plug-and-play devices.

• They shield devices one at a time like televisions, computers, and WiFi routers.

• Complete protection requires using Type 1 or Type 2 SPDs alongside Type 3s.

Real Life Application of Surge Protection Device

Below are the top real life applications of Surge protection devices. 

Lightning Strike Near the Home

Imagine a thunderstorm where lightning hits a nearby power line. The strike causes a high-voltage surge that travels through the utility line and into your home’s wiring. This sudden spike can instantly damage your appliances, computers, or other sensitive electronics, unless a surge protection device is already in place to stop it.

Type 1 SPD at the Main Distribution Board

A Type 1 SPD installed at the main distribution board acts as the first shield. It diverts the bulk of the incoming surge energy away from your electrical system, sending it safely to the ground. This ensures that the majority of harmful voltage is intercepted before it reaches your indoor circuits.

Type 2 SPD for Internal Circuit Protection

Even after the initial surge is handled, a small amount of residual voltage may still enter the system. A Type 2 SPD is installed inside the main panel to manage this leftover surge. It offers secondary protection for internal wiring, safeguarding household appliances and electrical components from mid-level surges.

Type 3 SPD at the Device Level

Type 3 SPDs are used at the outlet level where you plug in electronics. These surge protectors add a final layer of defense, especially for highly sensitive devices like televisions, gaming consoles, and computers. They neutralize any remaining surges. Also, they help prolong the lifespan of your equipment.

Schneider Electric Surge Protection Device

Schneider Electric surge protection device options rank as some of the most reliable. Schneider has a broad portfolio of SPDs specially designed for homes, businesses, and industrial settings.

Our SPDs are recognized for:

• Exceptional Reliability

• Rapid Activation

• IEC Compliance

• Compact and Modular Configuration

Schneider Electric SPDs are available at most electrical retailers and on our eShop. Depending on the model, the devices provide protection ranging from 20kA to 65kA.

Surge Protection Device Price in the Indian Market

Let us dive into the particulars.

In India, the surge protection device price varies based on device type, current rating, manufacturer, and intended application. Here is an overview:

Type	Price Range (INR)	Application
Type 1 SPD	₹3,000 – ₹8,000	Industrial, commercial
Type 2 SPD	₹1,500 – ₹4,500	Homes, offices, retail spaces
Type 3 SPD	₹300 – ₹1,000	Computers, routers, TVs, etc.

As an illustration, models from Schneider Electric eShop sit in the mid to upper range of the market, but due to their high quality and reliability, the price is justified.

As a final note: while there are cheaper alternatives, don’t forget that unbranded and budget SPDs may fail to activate in a timely manner during a surge, leading to potentially damaging situations.

Things to think about when Selecting and Installing SPDs

Here are important things to take note about as far as selection and placement of surge protection devices is concerned:

• Verify that the voltage and current rating is appropriate for your system.

• Ensure it complies with IEC 61643 or IS/IEC 61643-1 standards.

• Prefer modular SPDs for easy replacements.

• For homes, install at least a Type 2 SPD at the main panel.

• Remember to connect the SPD to the earth/ground line as this is very important.

It is important to place and install SPDs correctly and with an electrician to ensure placement is optimal.

Also Read: Various Types of Circuit Protection Devices That Prevents from Electrical Losses

Conclusion

Without a doubt, power surges are an omnipresent threat in a technology-driven society. They are an ongoing menace for modern electronics. During a power surge, a surge protection device ensures that electronics don’t incur unnecessary damages.

If your concern is balancing between a surge protection device for home use or an industrial one, reviewing the surge protection device working principle should assure smarter decisions down the line.

Next time there’s a thunderstorm or random power outage, with an SPD in place, you can feel assured that all your devices are safely protected.

FAQ's

Q1. Can a surge protection device prevent damage from power outages or voltage drops?

Ans: Surge protection devices are designed to protect against voltage spikes or surges, not power outages or voltage drops (sags). For issues like voltage dips or brownouts, other devices such as voltage stabilizers or UPS (Uninterruptible Power Supply) systems are more appropriate.

Q2. How do I know if my SPD has been damaged or needs replacement?

Ans: Most high-quality SPDs come with visual indicators (LEDs) or mechanical flags that show the operational status. If the indicator shows a fault or failure, it means the SPD has absorbed a surge and should be replaced. In the absence of indicators, regular inspection by a qualified electrician is recommended, especially after a lightning storm or power event.

Q3. Do I need a surge protection device if I already use an inverter or UPS?

Ans: While inverters and UPS systems offer some protection, they are not substitutes for SPDs. Surge protection devices specifically deal with high-voltage transients, which inverters and UPSs may not be able to handle effectively. In fact, installing an SPD prolongs the life of your UPS by shielding it from surge damage.