SPD to protect GFCIs

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tersh said:
When a MOV (metal oxide varistor) is near end of life (from many small surge strikes over span of time), it would conduct at lower and lower voltage until it can even conduct with regular voltage say 120v (from the MCOV of 150v), then it would go into thermal runaway (burn) because of the continuous conduction. Can anyone give example of any 120v GFCI receptacle with burnt MOV. Doesn't it burn the entire receptacle since the housing is plastic?
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When MOV fails at more than four times it's rated JOULES, it explodes or vaporizes. No conduction occurs when this happens because after explosion it is reduced to small pieces.

The case is made of high temperature molded ceramics—not plastic.

This feature is used to gain approval from UL because they are exposed to high temperature measured in joules.

During it's lifespan, it safely dissipates the heat caused by spikes. UL 1449 approves MOVs that safely dissipate energy to ground at rated joules below the safe limit.
In other words, if it fails within their set benchmark—it is good and approval follows.

However, there is a problem with this practice.

Not all surges are created equal. In order to have effective protection, you would need multiple arrangement of MOVs that will handle all levels of surges and different installation techniques of electricians who are going to implement this (supposedly) “life-saving” protection.
Some surges even emanate locally-- that is-- inside the house. Relays going off and on, motors, transformers etc.

Electricians know what MOV does. . . but that knowledge is not enough.

Electrical concepts are too complex and learning the technology is far more important than simply knowing how they work.

Only through this rounded knowledge can we have a reliable fault-proof SPD that will benefit consumer--and not being used by insurance companies as cow cash like others had been snivelling about.




.
 
Adamjamma said:
HMMM... in the US or Europe, might work. In Jamaica... we cannot even get accurate hurricane reports on the weather alerts... lol.
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Hey, I was born and lived most of my life in Miami. The cruise boats here say it never rains in Jamaica!

I've been there, beautiful place!

I had many of your brothers work as PM's in my shop. Great guys and hard workers. They had the patience that I have NONE of. I would always send them to get permits because I couldn't stand the bureaucracy of Dade County, which is Miami.
 
myspark said:
When MOV fails at more than four times it's rated JOULES, it explodes or vaporizes. No conduction occurs when this happens because after explosion it is reduced to small pieces.

The case is made of high temperature molded ceramics—not plastic.

This feature is used to gain approval from UL because they are exposed to high temperature measured in joules.

During it's lifespan, it safely dissipates the heat caused by spikes. UL 1449 approves MOVs that safely dissipate energy to ground at rated joules below the safe limit.
In other words, if it fails within their set benchmark—it is good and approval follows.

However, there is a problem with this practice.

Not all surges are created equal. In order to have effective protection, you would need multiple arrangement of MOVs that will handle all levels of surges and different installation techniques of electricians who are going to implement this (supposedly) “life-saving” protection.
Some surges even emanate locally-- that is-- inside the house. Relays going off and on, motors, transformers etc.

Electricians know what MOV does. . . but that knowledge is not enough.

Electrical concepts are too complex and learning the technology is far more important than simply knowing how they work.

Only through this rounded knowledge can we have a reliable fault-proof SPD that will benefit consumer--and not being used by insurance companies as cow cash like others had been snivelling about.




.
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Let me know when humans make the "fault proof" SPD. LOL
 
tersh said:
Can anyone give example of any 120v GFCI receptacle with burnt MOV. Doesn't it burn the entire receptacle since the housing is plastic?
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Not a receptacle, but I have seen several power strips burn up like a Roman candle. One right before my eyes. I believe we had a discussion here several years ago about the cause of a fire. It was clear from the picture that a power strip that was shoved under a desk which powered a computer and other equipment was the cause of a fire that destroyed the whole room.

Here in this country with our grounded receptacles, you cannot use a surge protector on the load side of a GFCI receptacle or a circuit protected by a GFCI breaker. This is because the MOVs are from each side to ground and the normal transients that occur will cause conduction from hot to ground and cause the GFCI device to nuisance trip.

-Hal
 
hbiss said:
Not a receptacle, but I have seen several power strips burn up like a Roman candle. One right before my eyes. I believe we had a discussion here several years ago about the cause of a fire. It was clear from the picture that a power strip that was shoved under a desk which powered a computer and other equipment was the cause of a fire that destroyed the whole room.

Here in this country with our grounded receptacles, you cannot use a surge protector on the load side of a GFCI receptacle or a circuit protected by a GFCI breaker. This is because the MOVs are from each side to ground and the normal transients that occur will cause conduction from hot to ground and cause the GFCI device to nuisance trip.

-Hal
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I too have seen a power strip grenade on a carpet (put quite a burn mark in the carpet) but this one suffered lightning damage.
Your 2nd statement I’ve often pondered and see I’m not the only one who believes that GFCI will see ground fault when the MOV conducts to ground durring a spike.
 
Feel free to use my bathroom. My wife got one of those "outlet expanders" that also happens to incorporate surge protection, and stuck it into the GFCI receptacle so we can plug in a hair dryer, electric tooth brush, night light, my shaver charger and the cat's water bowl that has a recirculating pump. Every so often I hear "Hal! The hair dryer won't work or the night light is out" and I have to pull the whole thing out to expose the buttons on the receptacle to reset it.

I keep saying I'm going to see if I can get it apart and clip those damn MOVs out but I'll probably get to redoing the bathroom first and install more receptacles.

-Hal
 
hbiss said:
. . . I have to pull the whole thing out to expose the buttons on the receptacle to reset it.
Click to expand...
How about drilling a carefully-placed hole through the extender that lines up with the reset button, and installing a plastic push rod through it?
 
I have seen MOV that burns when it reaches above MCOV (Maximum Continuous Operating Voltage). For 120v. The MCOV is 150v. But after years of regular surge hits, the MCOV can become lower and lower until it reaches 120v. Then the MOV burns. Some strip surge protection enclosure even got burned.

JmW2Fr.jpg


I'd like to see sample of the GFCI receptacle getting burned. Or is there no sample yet because the ones with MOV still hasn't reached the end of life. This means 5 or 10 years later, we would suddenly have increase of burning receptacles in the US?
 
GFCI devices seemed to fail often enough in years past. Often enough it would be after storms rolled through the area. They seemed to get better at withstanding those disturbances and even better yet since the WR and self testing have come about. Could be they are just new enough yet. The older ones usually just quit working, either not tripping or not resetting.
 
don_resqcapt19 said:
The UL product standard was already changed to increase the amount of surge protection within the GFCI itself, but there is limited space in the device. Not sure anything more can be done with the device itself.
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I agree that there is only so much that can be done within the device but no matter what you do the surge is going to get it eventually. So rather than add more complexity by requiring service surge protection that may or may not even be effective, let the surge destroy the GFCI but make it fail-open so that it will be obvious it needs to be replaced.

Don't smokes require a battery backup? Failure mode would be indicated by a beep that could only be silenced by removing it.

If enough devices are damaged in a unacceptable span of time, let the owner be the one to decide whether or not to install a service surge protector.

-Hal
 
hbiss said:
... let the surge destroy the GFCI but make it fail-open so that it will be obvious it needs to be replaced. ...
-Hal
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The GFCIs are already required to be self-testing, but they are not required to fail open..they are permitted to fail open, or indicate failure using an audible and/or visual alarm. I guess they could change UL 943 an require a fail open device and leave the surge protection up to the owner. Not sure about AFCIs as far as self testing.
 
pbeIP4.jpg



This item finally arrives. It can protect the 10 GFCI outlets in the average homes of millions of people, right? This can divert the surges to it and make the MOV in the GFCI receptacle not burst into flames, and burn the house (if the house is not concrete but wooden).
 
tersh said:
pbeIP4.jpg



This item finally arrives. It can protect the 10 GFCI outlets in the average homes of millions of people, right? This can divert the surges to it and make the MOV in the GFCI receptacle not burst into flames, and burn the house (if the house is not concrete but wooden).
Click to expand...

If Jesus comes back to earth, he would bless it as a miracle!
 
This item finally arrives. It can protect the 10 GFCI outlets in the average homes of millions of people, right? This can divert the surges to it and make the MOV in the GFCI receptacle not burst into flames, and burn the house
Click to expand...

That's the most ridiculous statement I ever heard. So now you are on a crusade to protect people from what you seem to think are dangerously designed or manufactured products? I can tell you this: if even ONE GFCI receptacle ever burst into flames and burned a house down, the people in that house wouldn't have to worry about money for the rest of their lives. So you can bet that isn't going to happen.

-Hal
 
tersh said:
pbeIP4.jpg



This item finally arrives. It can protect the 10 GFCI outlets in the average homes of millions of people, right? This can divert the surges to it and make the MOV in the GFCI receptacle not burst into flames, and burn the house (if the house is not concrete but wooden).
Click to expand...

Only 10? Why 10? It says whole house. Suppose I have 11, how does it know which 10 to protect?
 
“FirstSurgeTM is GRM-equipped notifying you a rare safety hazard exists due to a compromised electrical system neutral to ground bond. What will you see and hear when this occurs?
Audible Alarm: Beeps Green LED(s): Remains Lit Red Service Light: Flashes”

What will those millions do when this device detects they have no neutral to ground bond?
 
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