Power Cords/ Conditioner/Surge Protectors

Nearly all surge suppressors use MOV’s.

MOV’s fail silently with no warning. They go bad from repeated micro-surges. It is recommended by many that you replace your surge suppressors every year or 2 depending on where you live.

 

I lost $14,000.00 worth of AVR, BD player, and projector to a failed surge suppressor. The worst part is that I knew that they can fail silently, and did nothing about it.

Any idea what created the surge?

Direct lightning strike?

A utility power overvoltage surge?

Other?

An MOV will not protect from a direct lightning strike or from a utility overvoltage event. They are designed to protect from a high overvoltage transient event that only lasts for a micro to a few milliseconds. In less than a blink of an eye. An MOV will clamp the transient in one nano second or less.  You are wasting your money on cheap SPD power strips. 

FYI, a plug-in type 3 SPD will not protect from a high voltage transient surge or spike, if the branch circuit wiring the SPD is plugged into, is less than 30ft from the main electrical service panel. In this instance the length of the branch circuit wiring matters.

The first line of defense to divert a nearby lightning strike or a Utility power company high voltage transient surge to mother earth ground, is a low resistance System Ground, Grounding Electrode System, connection to mother earth for the main electrical service ground. IEEE recommends 5 ohms or less. Simple Ohms Law is at play. The lower the ground Electrode to soil resistance the better.

Next line of defense is a good Type 1 (at service meter) or Type 2 (at main electrical service equipment disconnecting means) at the electrical service panel.

If the above conditions are not met, the ability of the plug-in Type 3 SPD to protect the connected loads, is greatly diminished.

The best protection for audio equipment during thunderstorms is to unplug the equipment from the AC mains outlet(s).

I lost $14,000.00 worth of AVR, BD player, and projector to a failed surge suppressor.

Internet connection? Wire Coax Cable to your house or Fiber Optics. If wire Coax Cable, was it, is it, properly grounded to the Electrical Service System Ground before it enters your house?

If Fiber optics it needs to enter the house.

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The surge was caused by a pole mounted transformed that exploded.

it blew the top right off and it burned until the fire department put it out. 

That was not a transient surge. That was high voltage overvoltage created by the high voltage primary winding crossing over onto the low voltage secondary winding. I assume after hopefully a very short length in time the primary high voltage fuse blew at the pole and opened the high voltage to the transformer.

I do not have any idea what the Utility company’s high voltage to ground voltage is in your area. In my area the voltage is around 7.9KVac to ground.

In the event of an electrical high voltage to Low voltage fault a good portion of the high voltage is taken to ground at the pole. The primary neutral is connected to the secondary neutral outside of the transformer and then connected to a ground wire that is fastened to the pole to the bottom of the pole where it is connected to a ground rod. (Sometimes the ground wire is connect to a square plate on the bottom of the power pole.)

The high voltage, voltage drop to earth soil, is determined by the soil to ground rod resistance. The lower the resistance the greater the high voltage to earth.  The higher the resistance the greater the voltage drop to earth, the remaining high voltage will be on the power line feeding the electrical service of your home. There it runs into another earth connected ground. Any high voltage on the power transformer neutral conductor will again go to ground through the Grounding Electrode System of the Electrical Service. Again the lower the electrode to soil resistance the better.  (Electrode is usually two, minimum, 5/8" X 8ft ground rods driven into the earth.)

The remaining high voltage on two Hot conductors will enter your home.

The high voltage may be only on one Hot line, leg. Or it may be on both.

My computer, server and modem are in different rooms, and had fairly new surge suppressors, so they survived just fine. My printer though was unprotected and was also a casualty.

One thing that can make a difference is the length of the branch circuit wiring from the main electrical service panel. 30ft is the minimum for a Type 3 plug in SPD. The longer the length of the branch circuit wiring from main electrical panel the greater the inductance in the wiring.  

FWIW, I’ve heard stories of an SPD sacrificing itself during a overvoltage event to save its’ connected load. I assume you replaced the SPD. If not, I would.

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Your point about internet is a very good one. I use subnets in my house to isolate IoT devices for security. My 2 channel system uses fiber ethernet, so it is safe from internet spikes.

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I lost $14,000.00 worth of AVR, BD player, and projector to a failed surge suppressor. The worst part is that I knew that they can fail silently, and did nothing about it.

Did you have internet connected to this equipment?

Is the internet that that enters your home Fiber or wire?

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