How to choose the best surge suppressor?

Electrical storms are one of the main causes of voltage spikes or transients in the electrical grid. Experts estimate that 44,000 storms occur every day, generating around 8 million electrical discharges per day.

When these events occur, a surge suppressor acts as a barrier to the transient and diverts it to ground. How? Suppressors are made up of varistors. These are what direct the excess voltage to ground, preventing it from reaching the devices they are protecting. The discharge capacity of varistors depends on how intense the transient is and how long the voltage spike lasts. Although they can sometimes perform multiple discharges without being damaged, in the event of intense or prolonged surges, they can only protect a single discharge, which means they are consumable in those situations.

It is important to note that suppressors do not protect against sustained surges. For those cases, solutions such as voltage regulators or UPS are required.

So, which suppressor should I choose to ensure that my devices are fully protected? Below, we will review a detailed guide that will allow you to choose the most appropriate solution for your needs.

Which surge suppressor is most suitable?

This four-step guide aims to present you with all the available options, so that making a decision becomes an easier task.

1. Identify the problem

First, it is important to identify whether you are in an area with high electrical activity. Or, which devices could be generating transients within your own installation. Currently, there are various resources available to find out the level of electrical activity in each region. One of them is the Global Lightning Location Network, a network that monitors the activity of natural electrical discharges across the Earth.

Subsequently, a power quality analysis can be used to determine which electrical faults are affecting your installation. This study is carried out by trained personnel using specific technology, which allows for more accurate results.

2. Look for available options

Secondly, you need to consider what types of surge suppressors are available on the market. UL 1449 is one of the standards that determines how surge suppressors can be classified into categories. There are currently five categories. Each one varies according to where the suppressor is installed: Type 1 (connected directly to the transformer), Type 2 (connected to the main panel or service entrance), Type 3 (connected to the secondary or distribution panel), Type 4 (multiple suppressors assembled), and Type 5 (connected directly to sensitive machinery or equipment).

3. Consult the most complete solution

Once we have identified the available models, it is also important to take into account the step voltage. This term refers to the path traveled by the transient from the moment it hits the transformer until it reaches your electronic equipment.

As mentioned above, depending on the magnitude and duration of the transient, there are certain suppressors that can only withstand one discharge.

Generally, suppressors are designed to operate at 25% or 30% above the nominal voltage. That is, in a 127 VAC suppressor, the discharge voltage acts at 160 VAC. Surge suppressors are classified by voltage and by the capacity in kiloamperes (KA) that they can drain to ground. A 200 KA suppressor has a greater discharge capacity than a 100 KA suppressor.

Cascade architecture

To prevent a single piece of equipment from being impacted by transients, it is best to opt for a cascade solution, which consists of installing a Type 1 suppressor on the transformer, then installing a Type 2 or 3 suppressor in the installation, and finally placing a Type 5 suppressor directly to protect sensitive devices such as machinery, data centers, UPS, among others. In cascade installations, Type 1 suppressors have the highest KA capacity, Type 2 and 3 have the lowest capacity, and finally, Type 5 have the lowest KA capacity.

When using a cascade architecture, each surge suppressor acts as a shield, reducing the intensity of the transient. This means that by the time it reaches the suppressor that directly protects your sensitive equipment, the force of the transient is minimal.

In terms of installation, it is always recommended to place the suppressor as close as possible to the load or panel to be protected. The fundamental principle is that the surge should travel the shortest distance to ground to prevent it from reaching the load. The capacity of the suppressor in KA must be calculated based on the short-circuit capacity at the installation site.

4. Consider the installation of the equipment

Finally, once you are familiar with all the available solutions, consider the installation location. Ask suppliers what is needed for the installation to be carried out smoothly and for the suppressor to function properly.

One of the measures that must be taken into account to achieve the above-mentioned objective is to ensure that you have good physical grounding. If the conditions in which the suppressor will be installed are well prepared, the device will be able to work optimally.

Now you can choose the right surge suppressor or the most complete solution for your installation. Do not hesitate to contact the manufacturer or supplier to get started and protect your devices as soon as possible.

Surge suppressors are a key element in your installation

At Industronic, we are committed to providing you with the most appropriate power quality solutions for your needs, from a power quality study to the installation of a suppressor and the relevant technical support.