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OVER-VOLTAGE PROTECTION

unit_399

unit_399

EL CAPO
I Support WorldwideDX.com!
Jun 17, 2008
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ALEJANDRIA, COLOMBIA SA
Just recently, a HUGE lightning storm rolled through our area of Colombia. We had a direct lightning hit on our power lines, and lost power for several hours. I've installed over-voltage surge protection on everything on our farm, and fortunately we didn't lose anything to the power surge. Our neighbors weren't as fortunate, and lost their TVs, refrigerators, microwaves, and other electronics that weren't protected.

I always install a 130vac varistor on the line input of any electronics we buy because it's CHEAP INSURANCE !! I purchased 100 GE V130LA20A 130V 6.5KA Metal Oxide Varistors from a seller on Ebay, and it was one of the best buys I ever made. Just install one of the varistors across the AC line input to any device, and it will absorb any HV surges from lightning or whatever.

I've installed a varistor across the ac line input on all of my radio equipment, as well as across all of the wall plugs in our house and in my shop. Haven't lost a single piece of equipment since I did this. Persons that utilize cb or amatuer transceivers need to protect their equipment in the same manner. Having a tall antenna invites lightning, and protecting against it is a must !!!

The answer is to install a varistor across the ac line in ALL of your equipment. Just solder the varistor across the AC line where it enters the equipment, and then breathe easy. 73s.

- 399
 
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unit_399 said:
View attachment 18208 Just recently, a HUGE lightning storm rolled through our area of Colombia. We had a direct lightning hit on our power lines, and lost power for several hours. I've installed over-voltage surge protection on everything on our farm, and fortunately we didn't lose anything to the power surge. Our neighbors weren't as fortunate, and lost their TVs, refrigerators, microwaves, and other electronics that weren't protected.

I always install a 130vac varistor on the line input of any electronics we buy because it's CHEAP INSURANCE !! I purchased 100 GE V130LA20A 130V 6.5KA Metal Oxide Varistors from a seller on Ebay, and it was one of the best buys I ever made. Just install one of the varistors across the AC line input to any device, and it will absorb any HV surges from lightning or whatever.

I've installed a varistor across the ac line input on all of my radio equipment, as well as across all of the wall plugs in our house and in my shop. Haven't lost a single piece of equipment since I did this. Persons that utilize cb or amatuer transceivers need to protect their equipment in the same manner. Having a tall antenna invites lightning, and protecting against it is a must !!!

The answer is to install a varistor across the ac line in ALL of your equipment. Just solder the varistor across the AC line where it enters the equipment, and then breathe easy. 73s.

- 399
Click to expand...

Thank you for confirming to all those naysayers that a simple MOV on the power leads can indeed make a big difference. Too many people think that there is NO protection against lightning. They are wrong. Nothing is 100% failsafe but there are indeed a lot of things that can be done cheaply that help a lot.
 
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I will look into this further myself. Never can be too cautious with lightning or even a surge!! Thx for the info 399. Have a good day.
 
unit_399 said:
I always install a 130vac varistor on the line input of any electronics we buy because it's CHEAP INSURANCE !! I purchased 100 GE V130LA20A 130V 6.5KA Metal Oxide Varistors from a seller on Ebay, and it was one of the best buys I ever made. Just install one of the varistors across the AC line input to any device, and it will absorb any HV surges from lightning or whatever. I've installed a varistor across the ac line input on all of my radio equipment, as well as across all of the wall plugs in our house and in my shop. Haven't lost a single piece of equipment since I did this. The answer is to install a varistor across the ac line in ALL of your equipment. Just solder the varistor across the AC line where it enters the equipment, and then breathe easy. 73s.
Click to expand...
FYI to ALL; this is no longer recommended. In fact, at the time of 399 posting this, I installed a few of these in some power bars and in one AC socket in the home. I will be removing ALL of the installed MOV's and replacing them (maybe) with TMOV's.

A thread on QRZ.com outlines the dangers that are now known along with examples of failures. These devices fail with a short and catch fire. If we are lucky, our house doesn't burn down in the process.
1280_o0chsZktn8N942Dc.jpg

​

 
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I don't think installing them across the outlet in the wall is a good idea. Probably not up to code either. However, if you install it inside a device, AFTER an appropriately rated fuse, I wouldn't worry. It's meant to pop a fuse in lower current devices, not necessarily a possible 30A breaker. Think reverse-protection diodes in dc, same idea, pops a fuse if the fuse is sized appropriately. I will go check the QRZ thread and see if my opinion changes. Not holding my breath.
 
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they have whole house protectors,
installed at the breaker box.

_AC_SX569_.jpg


Astron power supplies have a MOV installed in them,
after the 120 VAC line fuse. mounted right at the transformer.

when I was working in the marine electronics industry,
and using Astron power supplies for the VHF radio, radar,
and other electronics, we usually cut this MOV out.
There are lots of voltage fluctuations on them tug boats
and work boats, from the generator, and this MOV would
short out, as it should, but would cause vital electronics
to not work anymore.
 
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Don't most power supplies, surge strips, and most all electronics that have AC surge protection have these wired in?
I have may power strips from top brands like APC, Belkin etc. as well as a APC h15 for my TV and entertainment system that most likely have an MOV.
I also have a https://www.purecleanpower.com/power-perfect-box installed at my breaker panel.
Seems like a lot of them out there. Seems there would be a large recall or warning about these. I haven't read the QRZ thread yet, but I'm going to in a minute or so.
Not dissing, just commenting.

 
Smokinone said:
Don't most power supplies, surge strips, and most all electronics that have AC surge protection have these wired in?
I have may power strips from top brands like APC, Belkin etc. as well as a APC h15 for my TV and entertainment system that most likely have an MOV.
I also have a https://www.purecleanpower.com/power-perfect-box installed at my breaker panel.
Seems like a lot of them out there. Seems there would be a large recall or warning about these. I haven't read the QRZ thread yet, but I'm going to in a minute or so.
Not dissing, just commenting.

Click to expand...

You are correct sir, and I don't think the issue is with the mov as a whole but with manufacturing quality and application. A $5 power strip using bottom bids for manufacturing is dangerous, using quality MOV's within their designed application specifications is safe. My opinion remains unchanged. As with everything, quality, not quantity.
 
Well, I haven't read the complete 102 pages of the thread, but got this far:

WB2WIK said: ↑

I'm sure we'd all love to know the "root cause" if the fire investigators can find it; that could be pretty educational, to file under "What you never expect, but it can happen anyway."
:(
Click to expand...

I can't say anything officially but odds on favorite is a cheap plastic power strip that the 65" TV was plugged into flamed out.


johnsonfrancis.org

Potential Hazards of Metal Oxide Varistor (MOV) - Johnson's Techworld

Metal Oxide Varistor is often used as a surge and spike protector in electronic circuits. They function by shunting the extra current as their resistance drop markedly beyond the threshold voltage. As they are designed to conduct significant power for very short duration of the order of...
johnsonfrancis.org
 
My neighbor had a battery charger in his boat, one of those fancy bass pro shop ones meant for boats. We had a nearby strike and his charger took a hit. Inside was a 14241 240v MOV split in half and a blown fuse. Replaced both and it worked perfectly. I too bought 100 of them, but admittedly, I still haven't got the ambition to put them inside anything. I think I am going to make a custom power strip for my new bench and install them there instead of inside the equipment.

I am in the middle of redoing my whole bench so I am glad I saw this thread to remind me.
 

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