Very nearby lightning strikes can make the 120VAC Grounded wire go up to Millions of Volts, which is generally Zero Volts. With Ground being that high, 120VAC looks like Zero Volts compared, so the lightening strike Voltage comes in backwards to the two phases of city power. A Surge Protector Clamps the Voltage to about 300V which does help prevent damage to sensitive circuits. The bad thing about Surge Protectors, which most people don't know, is that they are typical only good for one very nearby lightening strike. They can and do go bad when the Voltage is that high. The Surge Protector will still pass 120VAC, but will no longer protect against lightening strikes. All Surge Protectors in the house or business would have to be tested, but most people won't have your generator or even know to have to test them. This is for the extension cord breakout outlet type, but you'd have to know if the whole house version can actually withstand that or not. A claim is one thing, but actual performance is another. But it was a great detailed explanation of how they operate and how to install a Whole-House Surge Protector!
I worked in the oil field & we had surge protection on our well control panels (480V 3Ø. It wasn't unusual for lightning to pop the surge protector & leave a hole in the can. It didn't vaporize the wires. So the surge protection can still be HOT after a lightning strike.
Nice! I've wondered about testing MOVs. In my main panel and solar combiners I've installed a couple of large Silicon Oxide Varistors (Delta LA 302 IIRC) which are supposedly self-healing. But I have a lot of point-of-use MOVs I need to test.
Checking resistance on a device at the same time you are applying voltage to it is a no no. How is the meter checking resistance with a voltage being shoved into it.
Yes Great topic. I was going to buy an insulation tester to test MOVs to see when they break down to see if they are still calibrated/operational/usable. I did some research and thought I could build a DIY tester. I was going to rig up a microwave oven transformer to a full wave rectifier to generate my 1000 volt DC source. I guess I could just use the high voltage rectifier that came with microwave for half wave rectifier since there is no real load. I was going to slowly increase voltage on primary windings of MOT transformer with my variac and have a current limiting resistor in series with its DC output. I want to control the output voltage so as to NEVER exceed 1000 volts DC since all of my gear can't tolerate these voltage levels. I also wanted to use this device to test unknown rectifiers to see what their actual reverse breakdown voltages are. I have heard that some rectifiers are actually labeled with lower voltage levels than they actually are built for. Thanx for the great content.
Thanks for the MOV tutorial. I have two questions though. ... (1) Is there a reason that a (hand cranked) dynamo was used instead of a common bench supply? (2) I'm doubtful that the internal resistance of the Ammeter (DVM) would have any significant effect on the current measured. At least Not with a 270K resistor in series with it, as you have here. Did I misinterpret you? Wakodahatchee Chris
I have long mostly understood MOVs, but one thing unsure is, ok I get hot to ground, but why do most powerboards also go hot to neautral, Is this because when it breaks down and links them, both legs are temporarily at the same potential thereby theoretically making it safe for the device?
If you have a Transformer sitting on a pad on the ground then there's always a chance that lightning can strike the utility pole nearby that supplies power to your Transformer
@@electronicsNmore so then I definitely should protect it? I thought being underground couldn't make it anymore grounded but I didn't think about lightening hitting the box. I'm going to check to see if you linked it in the comments. Thanks again, I still get my best 'useless information' from you 😂
Great topic and great video!! Thank you!
Thank you! Glad you enjoyed the video. Looking forward to yours today!
Very nearby lightning strikes can make the 120VAC Grounded wire go up to Millions of Volts, which is generally Zero Volts. With Ground being that high, 120VAC looks like Zero Volts compared, so the lightening strike Voltage comes in backwards to the two phases of city power. A Surge Protector Clamps the Voltage to about 300V which does help prevent damage to sensitive circuits. The bad thing about Surge Protectors, which most people don't know, is that they are typical only good for one very nearby lightening strike. They can and do go bad when the Voltage is that high. The Surge Protector will still pass 120VAC, but will no longer protect against lightening strikes. All Surge Protectors in the house or business would have to be tested, but most people won't have your generator or even know to have to test them. This is for the extension cord breakout outlet type, but you'd have to know if the whole house version can actually withstand that or not. A claim is one thing, but actual performance is another. But it was a great detailed explanation of how they operate and how to install a Whole-House Surge Protector!
Yes, the unit I installed has an indicator LED to let you know if/when to replace it. Thanks for watching!
@@electronicsNmore That's very cool and so is that device. I didn't know whole-house surge protectors existed. Thanks for the video and reply!
The US... A third world country ... Unbelievable
In addition to my computer and TV, I am also using surge protectors on the refrigerator, washer and dryer.
you should! plus need whole house one too. one would have much less chance of something sparking inside wiring somewhere
I worked in the oil field & we had surge protection on our well control panels (480V 3Ø. It wasn't unusual for lightning to pop the surge protector & leave a hole in the can. It didn't vaporize the wires. So the surge protection can still be HOT after a lightning strike.
Thanks for the info', sir!!!
You're welcome!
Nice! I've wondered about testing MOVs. In my main panel and solar combiners I've installed a couple of large Silicon Oxide Varistors (Delta LA 302 IIRC) which are supposedly self-healing. But I have a lot of point-of-use MOVs I need to test.
SiC varistors are really good. Thanks for watching!
WOW! I needed this! Thank you
Could I assume an ‘EMP Shield’ wouldn’t protect my truck if an EMP targeted it?
Awesome video as usual. I wish you were my teacher when I was in school. Cheers.!!
Glad you enjoyed the video, and Thanks!
Does it make a difference if you put it on a lower breaker other then 1&3, I like it on 1&3 but I was told it didn't matter,
Good question. I think it would make a difference, but not too much because the bus bars are fairly wide and thick.
Excellent 👌
Glad you enjoyed the video Karry!
Can the MOV be distorted or go bad over time from repeated strikes? If so how would you know? Thanks.
Yes. Usually they'll have a spot on them blown out.
@@electronicsNmore Thank you.
Just got a lightning strike alert as I was watching your vid. We get hundreds per day here in St. Pete.
I lived in Sarasota years back, and there was a lot of lightning, far more than on the east coast of South Florida.
Checking resistance on a device at the same time you are applying voltage to it is a no no.
How is the meter checking resistance with a voltage being shoved into it.
How can I test the mov to know when it's going bad and is their anything I can add to the circuit as a simple indicator for such?
Is this louis rossmann brother that was lost at birth and didn't grow up in NY?
Yes Great topic. I was going to buy an insulation tester to test MOVs to see when they break down to see if they are still calibrated/operational/usable. I did some research and thought I could build a DIY tester. I was going to rig up a microwave oven transformer to a full wave rectifier to generate my 1000 volt DC source. I guess I could just use the high voltage rectifier that came with microwave for half wave rectifier since there is no real load. I was going to slowly increase voltage on primary windings of MOT transformer with my variac and have a current limiting resistor in series with its DC output. I want to control the output voltage so as to NEVER exceed 1000 volts DC since all of my gear can't tolerate these voltage levels. I also wanted to use this device to test unknown rectifiers to see what their actual reverse breakdown voltages are. I have heard that some rectifiers are actually labeled with lower voltage levels than they actually are built for. Thanx for the great content.
As usual, awesome demo & explanation eNm! Now I have to share this video with my stepson who is an electrician. Thanks! 👍👍👏👏
The was an extremely clear description of a surge protection device...thank you
Also protects against surges inside the house caused by other devices
Great demonstration. Thank you for the video.
still doing awesome videos i see thanks
great demo
Awesome video man. Very informative. Unlike most people on the internet
Glad you enjoyed the video Brian! Be sure to check out my extensive video playlists and share my channel with others. Thank you
Show me a video on how to install plug
Golden as always 🤗
Thanks for the MOV tutorial. I have two questions though. ...
(1) Is there a reason that a (hand cranked) dynamo was used instead of a common bench supply?
(2) I'm doubtful that the internal resistance of the Ammeter (DVM) would have any significant effect on the current measured. At least Not with a 270K resistor in series with it, as you have here. Did I misinterpret you?
Wakodahatchee Chris
I have long mostly understood MOVs, but one thing unsure is, ok I get hot to ground, but why do most powerboards also go hot to neautral, Is this because when it breaks down and links them, both legs are temporarily at the same potential thereby theoretically making it safe for the device?
using the hand electric generator is the best way to explain how the varistor works to limit the voltage spikes, Many thanks!!
Hey Doug, I was just thinking about you for some reason during Ian. Hope you faired well and avoided most of the mess!? 🙏
O
Any reason I might need a surge protector if my electricity is underground?
If you have a Transformer sitting on a pad on the ground then there's always a chance that lightning can strike the utility pole nearby that supplies power to your Transformer
@@electronicsNmore so then I definitely should protect it? I thought being underground couldn't make it anymore grounded but I didn't think about lightening hitting the box. I'm going to check to see if you linked it in the comments. Thanks again, I still get my best 'useless information' from you 😂
Thanks for sharing
Thanks Electric 🚹.
💯🖖
TIL: only buy things that support international residential voltages.
Oh wait, they should be a no-brainer!
Could you compare the MOVs to TranZorbs and gas discharge tube arresters, please?
P.S.: Great video, as always!
I happen to have 5 gas tube arrestors on hand. :-)
@@electronicsNmore And serie mode ;)