Tuesday, May 14, 2024

Myths and Truths of Lightning Protection

I found a widely read blog by Dan Robinson which discusses myths of surge protection which I wanted to respond to here. 

In it he makes some statements which are true, but not fully contextualized. He seems to argue against surge protection, while I absolutely argue for it.  Lets take a couple of his statements: 

MYTH: Surge protectors and UPS devices provide total lightning protection. [emphasis added]

He's right.  A direct strike, or one 10m from your home will probably be bad.  Dan uses examples of lightning jumping from an outlet to a faucet to illustrate what a direct or near miss could look like.  How often have you had that happen?  I fear that too many equate visible lightning strikes with damaging surges, and if they didn't see it nothing went wrong.  As someone who has lost gear due to electrical surges at least half a dozen times in his lifetime I can assure you that is not the case.  Your average surge capable of frying a personal computer is not visible but you may smell it when the MOV's in the power supply burn through.  I have, several times. 

Consider that when you assemble or disassemble a PC it is always recommended you wear a grounding strap around your wrist to prevent a static surge from damaging a component.  That is all it takes to damage a lot of electronics, especially high speed electronics like found in DAC's and streamers.  This is a billionth the current of a direct strike, and that's what we want to avoid in surge protection.

Here are more truths: 

  1. Most surge damage to electronic equipment is not from a direct or near-miss.
  2. Significant amounts of surge damage occur from non-storm related issues such as transformer failures.
  3. We can't always be aware of when a lightning storm will roll through.  

I fear Dan's position on surge protection, without more context, reads like the arguments against seat belts:

Seat belts won't prevent all accidental car deaths.

The arguments go something like  this:  "A seat belt wont' save me if a tractor trailer rolls over my car or if I drive off a bridge." That's probably true, but it is also true that they have reduced about 50% of all traffic fatalities when used. In 2023 this would amount to saving about 40,000 human lives in the United States.  So the questions you should ask include:

  • Are you sure you know what kind of a life-threatening accident you are going to have next?  
  • Are you sure you know when that accident will occur? 

I can guarantee you that everyone who died in a car accident in 2023 was not expecting to.  If you feel you can beat those odds, and don't mind being fined for not wearing one, please go ahead and remove your seat belt.

In terms of surge protection, Dan makes the argument that the best/cheapest protection is to unplug the equipment.  Oh my dear Goddess of Storms. He's correct, if you know when lightning is coming and you know it's going to be a near miss or worse because you are going to have arcs shooting across the room then that's the best thing to do.   It's a lot like saying "I'm not going to drive today because I know I am going to have an accident." 

Before you take Dan's implicit advice ask yourself if are you sure that: 

  1. The next damaging surge you suffer from will be from a near-miss or direct strike? 
  2. Do you know when it is going to happen so you can be around to unplug your equipment? 

Whole House Surge Protection

Another argument for surge protection is that the National Electric Code now requires a whole house surge protection device (SPD) in every new home.  They would not do this if they didn't feel it was a useful improvement. 

At the same time it's important to note that a whole house have high let-through voltages relative to the best surge protectors today, and the further your equipment is from the panel the more likely it is that an induced surge from a near by strike won't be clamped soon enough.  Based on actual third party testing I now recommend Furman with SMP and LiFT for the most expensive devices. 

Coaxial

Dan makes a very good point in his blog that coaxial lines can also be sources of damaging electrical surges.  For this I recommend an outdoor gas discharge unit.  Honestly I'm not about to unplug my cable modem every time lightning rolls around, so this may not be perfect but it is the best I'm willing to do.  Also, speaking of not knowing what will take your gear out, I used to have DirecTV and my receiver would blow not from lightning but from wind storms.  I guess the wind on the dish would build up a charge, and ZAP!  Yes, it was grounded.  It was the coaxial protection that saved me.  Also the Furman PST-8 has built in coax protection as well. 
 

Beware of scams! 

It's not exactly a scam but a lot of consumers get fooled into thinking that an expensive distribution block like this one is also a surge protector.   It is not.  It's nothing more than a glorified extension cord with an LED to tell you if it's plugged in.