[avamateur]

I have a new 10 outlet surge protector. I currently have an expensive tv plugged into it and two other inexpensive devices I dont care about. Can I make my Surge protector last longer by only having the tv plugged into. and will unused outlets be like "brand new" and ready if I need to switch outlets (ie one dies). Or am i Misunderstanding how surge protection works????


is there seperate surge protection for each outlet???

 

[kouack]

OMG hurry up to unplug every thing and store your surge protector in bubble wrap in a closet and will last you forever.

Seriously the surge protector will become ''TU'' when gonna be hit hard enough by a spike the reason you have lights on them saying good or bad. A surge protector will not wear because electrons flows true it. Your surge protector doesn't have 10 life because it as 10 outlet one good hit and gone.

 

[WonHung]



Quote:
Originally Posted by kouack /forum/post/15500620


OMG hurry up to unplug every thing and store your surge protector in bubble wrap in a closet and will last you forever.

Seriously the surge protector will become ''TU'' when gonna be hit hard enough by a spike the reason you have lights on them saying good or bad. A surge protector will not wear because electrons flows true it. Your surge protector doesn't have 10 life because it as 10 outlet one good hit and gone.

Part of your statement is incorrect. It depends on the type of surge protector. Most surge protectors use MOVs. While it is true that a surge protector will cease to function if it gets hit by a large enough power spike, it is also true a surge protector can have a gradual diminished service life. MOVs work by shunting excess power to ground. If the spike isn't large enough to fail the MOV, then over time if the MOV is exposed to enough spikes it will for all intents and purposes fail to function as a surge protector and can expose your equipment to any power spikes. Some manufacturers provide some sort of indicator of whether the MOVs are still functioning properly some don't.


The basic rule of thumb is after a certain number of years, you might want to consider replacing the surge protector depending on the quality of power service you get and the number/severity of electrical storms in your area.


Inserting a bunch of appliances will not degrade the surge protection ability of the surge protector. What you might do if you put enough current draw on the surge protector is to cause the internal wiring to overheat and thus create a fire hazard. Surge protectors come with a circuit breaker to help prevent over loading but again depending on the quality of the surge protector, the breaker may or may not do its job.

 

[avamateur]

yes I was referring to the gradual degradation and making it last longer.

Is the same set of MOVs connected to each outlet, or is there a seperate set per outlet?

Quote:
Part of your statement is incorrect. It depends on the type of surge protector. Most surge protectors use MOVs. While it is true that a surge protector will cease to function if it gets hit by a large enough power spike, it is also true a surge protector can have a gradual diminished service life. MOVs work by shunting excess power to ground. If the spike isn't large enough to fail the MOV, then over time if the MOV is exposed to enough spikes it will for all intents and purposes fail to function as a surge protector and can expose your equipment to any power spikes. Some manufacturers provide some sort of indicator of whether the MOVs are still functioning properly some don't.


The basic rule of thumb is after a certain number of years, you might want to consider replacing the surge protector depending on the quality of power service you get and the number/severity of electrical storms in your area.


Inserting a bunch of appliances will not degrade the surge protection ability of the surge protector. What you might do if you put enough current draw on the surge protector is to cause the internal wiring to overheat and thus create a fire hazard. Surge protectors come with a circuit breaker to help prevent over loading but again depending on the quality of the surge protector, the breaker may or may not do its job.

 

[duvetyne]

All outlets are in parallel, weather there is one set of MOV's or many, they're all in parallel, they all 'see' the same surge.

 

[11001011]



Quote:
Originally Posted by WonHung /forum/post/15500782


If the spike isn't large enough to fail the MOV, then over time if the MOV is exposed to enough spikes it will for all intents and purposes fail to function as a surge protector and can expose your equipment to any power spikes.

This is a myth spread my SMP type surge suppression device manufacturers.


While is is true MOV's do in a sense "wear out" they do so in the opposite manner that you say. What happens is their trigger point (Avalanche Voltage) begins to decrease over time and then it eventually falls below the average nominal line voltage causing total failure. When MOV's do fail they do not fail quietly, they fail short, burn up in a dramatic puff of smoke and flames, then become an open circuit.


People confuse this with losing it's ability to suppress a surge because the joule level the MOV can absorb with out failing is also reduced. But this does not matter because as I stated MOV's fail by becoming a short circuit. That short circuit will trip the breaker and disconnect your equipment from the power.

 

[WonHung]



Quote:
Originally Posted by 11001011 /forum/post/15503117

This is a myth spread my SMP type surge suppression device manufacturers.


While is is true MOV's do in a sense "wear out" they do so in the opposite manner that you say. What happens is their trigger point (Avalanche Voltage) begins to decrease over time and then it eventually falls below the average nominal line voltage causing total failure. When MOV's do fail they do not fail quietly, they fail short, burn up in a dramatic puff of smoke and flames, then become an open circuit.


People confuse this with losing it's ability to suppress a surge because the joule level the MOV can absorb with out failing is also reduced. But this does not matter because as I stated MOV's fail by becoming a short circuit. That short circuit will trip the breaker and disconnect your equipment from the power.

So which is it? When you say an MOV fails does it become a short or an open circuit as your post is contradicting itself.

 

[MauneyM]

Any surge suppressor meeting the current UL standards has internally fused MOVs, so it should not trip a breaker.


When MOVs have absorbed all of the energy they can, they fail to a dead short at the application voltage. When this occurs they will overheat, flame out and arc, resulting in a blown internal fuse in the TVSS device.


Thus, there is a dead short for an instant, then an open circuit. Without an indicator, you will never know when this has occured unless the MOV fails violently.

 

[11001011]



Quote:
Originally Posted by WonHung /forum/post/15503853


So which is it? When you say an MOV fails does it become a short or an open circuit as your post is contradicting itself.

Maybe I was not being clear, here is how a MOV works.


A MOV has a crystalline structure. As the voltage rises the crystals begin to align and it's resistance begins to drop. When the avalanche point is reached the majority of crystals are aligned and it's resistance is near 0. As the voltage drops the crystals begin to go back to random and it's resistance rises to near infinite.


As a MOV receives more and more surges more and more of the crystals do not return to the random state, they stay aligned. This causes it's avalanche point to drop.


A MOV fails either by a surge larger than it can pass or by the avalanche point becoming so low that normal operating voltage over heats the MOV.


A MOV fails in three stages...

The MOV will first become a short circuit.

Then the MOV will explode or just burn up due to thermal runaway.

Then the MOV will be an open circuit.


MOV's don't just quit working.


Trust me on this one, I have personally conducted surge testing on MOV's and various electronic devices at work using the surge generator pictured here.

On the left is a surge generator capable of applying surge pulses from 200V to 6.6kV at 1.2/50us (open circuit) and 8/20us (short circuit), as well as at 0.5us/100kHz damped oscillation, directly onto the power line to easily test for IEC, EN, Telcordia, or any custom profile.



On the right Electrical Fast Transient gererator (EFT) Burst test can test to 4.4kV, meeting and exceeding the IEC limits. This is for applying high frequency burst noise directly onto power lines or when used in conjunction with a "trench" EFT can be inductively coupled to power cords and interconnects.

 

[Chu Gai]

My binary friend knows his stuff. With respect to the OP, adding additional devices to your surge protector will not cause it to have a shorter lifetime. If you're concerned about surges because you live in an area known for lighting activity, maybe you should look into whole house devices assuming you've got your own home. It'll cost more though than a floor based unit but will provide protection to all the electronic devices in your home.

 

[WonHung]



Quote:
Originally Posted by 11001011 /forum/post/15504501


Maybe I was not being clear, here is how a MOV works.


A MOV has a crystalline structure. As the voltage rises the crystals begin to align and it's resistance begins to drop. When the avalanche point is reached the majority of crystals are aligned and it's resistance is near 0. As the voltage drops the crystals begin to go back to random and it's resistance rises to near infinite.


As a MOV receives more and more surges more and more of the crystals do not return to the random state, they stay aligned. This causes it's avalanche point to drop.


A MOV fails either by a surge larger than it can pass or by the avalanche point becoming so low that normal operating voltage over heats the MOV.


A MOV fails in three stages...

The MOV will first become a short circuit.

Then the MOV will explode or just burn up due to thermal runaway.

Then the MOV will be an open circuit.


MOV's don't just quit working.


Trust me on this one, I have personally conducted surge testing on MOV's and various electronic devices at work using the surge generator pictured here.

On the left is a surge generator capable of applying surge pulses from 200V to 6.6kV at 1.2/50us (open circuit) and 8/20us (short circuit), as well as at 0.5us/100kHz damped oscillation, directly onto the power line to easily test for IEC, EN, Telcordia, or any custom profile.



On the right Electrical Fast Transient gererator (EFT) Burst test can test to 4.4kV, meeting and exceeding the IEC limits. This is for applying high frequency burst noise directly onto power lines or when used in conjunction with a "trench" EFT can be inductively coupled to power cords and interconnects.

Thanks for the explanation. I recall some of what you've explained and it makes sense. But when the MOV fails, how does it affect the surge protector at that point. When the MOV is an open circuit, this implies there would be zero power being supplied to each of the recepticles in the strip. Is this correct?

 

[duvetyne]



Quote:
But when the MOV fails, how does it affect the surge protector at that point.

The MOV is the surge protector.

Quote:
When the MOV is an open circuit, this implies there would be zero power being supplied to each of the recepticles in the strip. Is this correct?

No, the MOV's are in parallel, if it goes open circuit, it's like it's not there....they're not in series with the load.

 

[WonHung]



Quote:
Originally Posted by duvetyne /forum/post/15511895


The MOV is the surge protector.




No, the MOV's are in parallel, if it goes open circuit, it's like it's not there....they're not in series with the load.

Yes, I know the MOV is the surge protector. I was using surge protector to describe the entire unit.


If the MOVs are wired in parallel to the actual power circuit, then that's not what happened with a surge protector I had which did take a huge power hit. I had a surge protector actually get field tested when a truck hit a utility pole feeding the lines to some homes in my cul de sac. Mine was one of them. The surge was so severe it tripped two breakers and zapped one of my surge protectors. The surge was hard enough where I can smell the burnt electronics in the strip and when you shook the surge protector you could hear rattling inside. With the surge protector plugged into the wall, I couldn't reset the breaker as something in the surge protector was shorting out the circuit.

 

[11001011]



Quote:
Originally Posted by duvetyne /forum/post/15511895


the MOV's are in parallel, if it goes open circuit, it's like it's not there....they're not in series with the load.

This is true but it's not like the MOV is going to fail unnoticed.


Smoke and fire usually accompany a MOV failing to the point of becoming a open circuit.

 

[saturation]

While I agree with our binary friend, A MOV can fail in between the extreme modes, from a violent flare to quietly, with open circuit and no protection provided the worse case scenario. A lot depends on the size of the overvoltage condition and its duration, or repeated surges over time, and it varies finally on the type of MOV used, because of its rated Maximum Continuous Operating Voltage, MCOV and the variability by which such is measured by manufacturers.


Few studies can be read free of charge, but a co-inventor of the MOV, Francois Martzloff, has made his entire library free courtesy of NIST, here is a 'real life' type scenario affecting a MOV in a complete design, not just isolated testing:

http://www.eeel.nist.gov/817/pubs/sp...0on%20SPDs.pdf


To minimize MOV failures without protecting circuits it was added to protect, most designs have thermal fuses that blow during the overheat phase of a surge. In addition, current fuses are added or built right into the MOVs. A good design then hinges on the response time of the fuses, which are more predictable and well established, to the variable responses of MOVs, and overall the final effect is to disconnect protected devices from the power line once the MOV has experienced a severe condition, even if the MOV is still usable, but now in the realm of unreliability. As the small study shows, the response of different UL certified SPD are variable. Finally, a good SPD design must have some indicator light that the unit provides surge protection or that it no longer works [in some models, a buzzer sounds if the surge circuitry is non-functional, and others the entire SPD has a non-resettable fuse that blows.]



For details, you can also read Standler's excellent text on surges and mitigation:

http://www.rbs2.com/fire.htm

Both Martzloff and Standler are online if you wish to chat with them and are among the top experts in the surge suppression field.

 

[saturation]



Quote:
Originally Posted by avamateur /forum/post/15499359


I have a new 10 outlet surge protector. I currently have an expensive tv plugged into it and two other inexpensive devices I dont care about. Can I make my Surge protector last longer by only having the tv plugged into. and will unused outlets be like "brand new" and ready if I need to switch outlets (ie one dies). Or am i Misunderstanding how surge protection works????

is there seperate surge protection for each outlet???

Alas, no. The surge suppressor circuitry protects all the outlets equally. You can consider the surge protection part as just a one plug variety that has a power strip plugged into it.

 

[duvetyne]



Quote:
If the MOVs are wired in parallel to the actual power circuit, then that's not what happened with a surge protector I had which did take a huge power hit.

If the MOV's were not in parallel, how were they wired?

You don't say how yours was wired, just that it's not in parallel...how do you know?

Quote:
The surge was hard enough where I can smell the burnt electronics in the strip and when you shook the surge protector you could hear rattling inside. With the surge protector plugged into the wall, I couldn't reset the breaker as something in the surge protector was shorting out the circuit.

PLease re read 11001011's post again, he explained this to you very well.

Quote:
This is true but it's not like the MOV is going to fail unnoticed.

I was under the impression he'd already read, and understood your post.

 

[WonHung]



Quote:
Originally Posted by duvetyne /forum/post/15516493


If the MOV's were not in parallel, how were they wired?

You don't say how yours was wired, just that it's not in parallel...how do you know?




PLease re read 11001011's post again, he explained this to you very well.




I was under the impression he'd already read, and understood your post.

I don't know as I didn't bother to crack open the surge protector to find out how the manufacturer wired it. I was going by your statement that the MOV is wired in parallel and if the MOV failed it would be like it wasn't there. Well, I'm telling you this is NOT what happened in my situation. Based on your statement, I should have been able to just keep using the surge protector with the only artifact being that the protect light would be un-lit indicating the surge protector is no longer effective against surges. As I stated, the spike nuked the components inside of the surge protector which created a short that prevented the breaker at the main panel from being reset.

 

[MauneyM]



Quote:
Originally Posted by WonHung /forum/post/15516892


I don't know as I didn't bother to crack open the surge protector to find out how the manufacturer wired it. I was going by your statement that the MOV is wired in parallel and if the MOV failed it would be like it wasn't there. Well, I'm telling you this is NOT what happened in my situation. Based on your statement, I should have been able to just keep using the surge protector with the only artifact being that the protect light would be un-lit indicating the surge protector is no longer effective against surges. As I stated, the spike nuked the components inside of the surge protector which created a short that prevented the breaker at the main panel from being reset.

This can happen for several reasons, but none of them invalidate what 11001011 write.


1) Some (better) TVSS devices also have series filters for some or all of the outlets. If the inductor in that circuit opened, then you would have no power available.


2) Some TVSSs (I can think of one particular design) intentionally open when the MOV has failed (the fuse is wired in the main line, not in the parallel MOV link). This is to force you to replace the unit when the protection no longer functions. [I personally HATE this - I prefer a visual indicator.]


3) When a MOV fails catastrophically, it can shatter and blow pieces all over the place. Given the type of failure you mention (likely a sustained over-voltage, rather than an average transient), this is quite possible. If a conductive piece falls into a place that shorts line-ground, something is going to give, and it will probably be a trace on the PC board. This may take longer than the feeding breaker will tolerate.


4) If the line fault you experienced placed medium voltage (2400, 4800, 7200, etc) across the input terminals, you could well have had a sustained arc inside the housing. Once this happens carbon tracking occurs, and the product is going to fail in a non-recoverable fashion - and again it may sustain conduction longer than the feeding breaker will remain closed.


[Before any design guys beat me up, I am using the term "sustained over-voltage" to mean anything longer than the half-cycle or so that it will take to cause the feeding breaker to trip in magnetic mode. This is in contrast to a transient over-voltage.]

 

[duvetyne]



Quote:
Well, I'm telling you this is NOT what happened in my situation

A number of people have explained that when the MOV shorts out with a heavy surge it causes the breaker or fuse to open, why do you keep ignoring that?