Surge protector secrets you're not supposed to know...

Everyone knows that a surge protector is necessary. It's typically an afterthought when buying a computer, stereo, industrial control panel, or any other expensive electronics.

Most give little thought to its purchase, simply buying whatever the salesman happens to be pushing. Many times it's only $20. Other times you are steered to a $129 protector. And you see all kinds of "connected-equipment" guarantees and claims about surge and spike performance.

What's really going on? Sit back and buckle up.

You're not going to believe what a scam most of these products are. Virtually all of them are designed incorrectly.

Parallel vs. Series

Parallel protection devices are placed across wires "hot to neutral," "hot to ground," and "neutral to ground." and dump spikes to ground. The problem? These spikes can travel through the ground wire and into your equipment. This is especially problematic for networks.

Most common parallel device? The MOV (Metal Oxide Varistor). These degrade over time and can even explode.

Other devices like gas discharge tubes and transzorbs behave similarly, dumping spikes onto the ground. All parallel-type devices have a delay and degrade over time.

So what's the solution?

Use a series-mode surge protector. These do not dump spikes to ground. Instead, they absorb and slowly bleed off the energy into the neutral wire, harmlessly.

Series-mode devices, like the ferro-resonant transformer, offer protection but can be bulky and expensive. Modern solutions exist that offer the same protection in a smaller, cooler, and more affordable package with no MOVs.

UPS Considerations

Most UPS units use MOVs and function like parallel surge protectors when idle. If using a UPS, place it downstream from a series-mode protector.

Common Mode vs. Normal Mode

Normal mode spikes occur between hot and neutral. Common mode spikes occur between neutral and ground and are usually created inside your building, often by parallel protectors themselves.

Telephone Line Protectors

Most plug-in phone line protectors are parallel type and can inject spikes into your system ground. Be cautious.

Real-World Sources of Spikes

Appliances in your home or business, like refrigerators, vacuum cleaners, microwaves, etc. can cause spikes. Even neighbors on the same transformer can generate them.

What the Government Says

New Federal CID standards now define endurance and performance categories for surge protectors. Series-mode devices pass Grade A tests. MOV-based devices often fail early in even Grade C.