APC's Current-Gen SurgeArrest: A Modern Tear-Down

[Guest]

After our first tear-down, APC wanted to send in a modern equivalent to demonstrate the company's dedication to quality. Follow along as we tear open another power strip and dig deep into its electrical composition.

APC's Current-Gen SurgeArrest: A Modern Tear-Down : Read more

 

[errdizzy]

I still don't touch APC products anymore. I used to have all TVs, computers and game systems in my house connected to them. It only took a year for the batteries in all of them to die (at different times). I switched the another manufacturer and haven't had a problem since. Going on 2 years now...

 

[jll544]

"Surprisingly, the new unit has higher surge suppression voltage ratings than the old unit"

Actually, not surprising because it's not valid to compare the ratings between the different generations. The old surge protector was rated under UL 1449 2nd Edition, whereas the new one was rated under UL 1449 3rd Edition. The 3rd Edition test applies a much higher current, so the higher voltage is expected.

 

[SWB02]

APC sent you this unit? If so, then knowing it would be subjected to a public teardown and critique, I expect they will have thoroughly inspected it beforehand to ensure it was a shining example of their absolute best workmanship.

Much more interesting would be a teardown of a unit obtained independently through normal retail channels.

 

[Peter Martin]

Tripp Lite power surge suppressors for me. ONLY. I would never use anything else.

 

[Peter Martin]

And I mean only the ISOBAR products.

 

[Daniel Sauvageau]

[quotemsg=14340106,0,58134]Actually, not surprising because it's not valid to compare the ratings between the different generations. The old surge protector was rated under UL 1449 2nd Edition, whereas the new one was rated under UL 1449 3rd Edition. The 3rd Edition test applies a much higher current, so the higher voltage is expected.[/quotemsg]
I wanted to take a look at that but could not find a free copy of it online; only various companies' notes highlighting differences relevant to their respective business. Without access to the original document, I have no idea how comprehensive and accurate those whitepapers's change lists are.

For example, GE's version does describe the new test conditions (6kV at up to 500A for 2nd vs 6kV input at up to 3kA for 3rd) but it is preceded by a mention that only type-1 and type-2 SPDs (meter/panel-mount) will be further discussed, which seemed to imply that the above was specific to those types.

 

[Daniel Sauvageau]

[quotemsg=14340759,0,1780977]APC sent you this unit? If so, then knowing it would be subjected to a public teardown and critique, I expect they will have thoroughly inspected it beforehand to ensure it was a shining example of their absolute best workmanship.[/quotemsg]
They most likely did at least check it out for any obvious issues but then again, the new design has fewer wires attaching to the PCB and none of them directly to the traces from the copper side, which should considerably reduce the potential for handling mistakes.

 

[merikafyeah]

Sacrificial surge suppressors are all well and good when you're on a budget, but they still don't hold a candle to non-sacrificial surge suppressors like those from Brickwall and SurgeX. All things considered, the cheaper Brickwall units are actually not THAT much more expensive than the most expensive sacrificial surge suppressors, and they are well worth every penny, especially considering you never need to replace them.

I recommend this unit in particular for its value/$:
http://www.brickwall.com/collections/surge-protectors-home-theater-hdtv/products/eight-outlet-audio-surge-protector

Made in USA, not China like almost every other surge suppressor you can buy today. You get what you pay for, and I learned the hard way with cheap suppressors.

 

[JackNaylorPE]

[quotemsg=14339730,0,1780809]I still don't touch APC products anymore. I used to have all TVs, computers and game systems in my house connected to them. It only took a year for the batteries in all of them to die (at different times). I switched the another manufacturer and haven't had a problem since. Going on 2 years now...[/quotemsg]

Agreed .... same here .... and replacing the batteries is not done because it's cheaper to buy a new unit. Since The Schneider take over, it's not the same company and certainly not the same product we used to see.

 

[Daniel Sauvageau]

[quotemsg=14341382,0,775985]Sacrificial surge suppressors are all well and good when you're on a budget, but they still don't hold a candle to non-sacrificial surge suppressors like those from Brickwall and SurgeX.[/quotemsg]
Do you happen to have an appnote or something that details how Brickwall/SurgeX's "non-sacrificial" surge protection works? Both companies have the exact same diagram that does not give any useful details about it.

Everything I can find about anything resembling that from other vendors effectively boils down to slapping an LC filter in front of the MOVs to block or dampen most of the high-frequency, high-energy stuff so the MOVs do not need to deal with (as much of) it.

 

[rdc85]

[quotemsg=14340759,0,1780977]APC sent you this unit? If so, then knowing it would be subjected to a public teardown and critique, I expect they will have thoroughly inspected it beforehand to ensure it was a shining example of their absolute best workmanship.

Much more interesting would be a teardown of a unit obtained independently through normal retail channels.[/quotemsg]

I don't see what wrong with that, most of review got their material from the company..
It's the same with GPU, CPU, mobo, phone, etc..
most (all) of them is supplied by the manufacturer,
the cost will be too much to handle, if all review need to buy the product and then sells it with lower price later..

But I'm agree, real market sample is much better and objective for review...

 

[mctylr]

First I believe Brickwall / SurgeX are simply two lines manufactured by the same company. There are simply induction based (hence in series with the AC lines) which limits rapid high frequency voltage changes.

I don't believe their claim "clamps 2V above peak" as inductors are not sharp (the proverbial "brick wall") filters, Ask anyone who has worked with hobby electronics or electric motors knows that back-EMF can easily be higher than the supply voltage. Though I don't think this configuration would generate back EMF, other than perhaps at power off.

Most surge protection (the so called "sacrificial" variety) are in fact shunt based designs that shunt the extra energy from an over-voltage event (at or above the clamping voltage). This includes Metal-Oxide Varistors (MOV), Transient Voltage Suppressor (TVS) diodes, Zener (Avalanche) diodes, potentially combined with a slower shunting device such as the gas discharge tubes, and most surge protection shunt devices do have a non-trivial failure rate.

Please find an EE to write about electronics. I'm not a professional, but even as a hobbyist I cringed at some of the lack of knowledge. See: EDN, EE Times, Clive Maxfield http://www.clivemaxfield.com/ the Amp Hour podcast, and even manufacturers such as Texas Instruments or OnSemi, are likely willing to offer their own in-house engineering staff to assist in such writing such articles.

 

[mctylr]

I believe APC suffered from the declining profit margins in the consumer market, before they were acquired by Schneider and now Eaton, and I think that (thin margins) is what caused their decline in quality, a rushed attempt to shrink their overhead in a market with thin margins.

Personally I do prefer brands that are better known in industrial / enterprise markets including TrippLite, and PowerWave (also owned by Eaton).

 

[mctylr]

[quotemsg=14346672,0,736169]
I don't see what wrong with that, most of review got their material from the company..
It's the same with GPU, CPU, mobo, phone, etc..
[/quotemsg]

The problem, which is the current norm in web based review sites, is that manufacturers have been repeatedly accused, rightly and wrongly, of cherry-picking the review samples. In fact in recent CPU reviews here, the reviewers have disclosed their opinions when samples are not as a "prime" as they expected that perhaps they didn't received hand-picked CPU samples for review purposes.

The US consumer magazine Consumer Report, published by their own not-for-profit organization has been considered a leader in unbiased reviewing because it has strict policies on only reviewing products that they buy themselves through normal retail channels.

This technique also works against fraudsters, who may provide a real (but expensive) review sample as a means of generating free marketing, but plan on selling low-manufacturing-cost (defective or fake) products in the market.

The ethics, and integrity of product reviews has a long and complicated history.

 

[Daniel Sauvageau]

[quotemsg=14349380,0,436284]Please find an EE to write about electronics. I'm not a professional, but even as a hobbyist I cringed at some of the lack of knowledge.[/quotemsg]
Not sure what you are cringing at since everything you said, I had already written and drawn - if you look at the simplified diagrams, you see the MOVs in shunt configuration, the inductors in series with live and neutral (ignore the MOVs with both terminals on the mains-side) and the capacitor across those L/N inductors to complete the LC filter.

This is a picture story for the typical THG reader; not a reference paper for EMI/SPD engineers and advanced hobbyists. With a target budget of about 750 characters per image (that's the editorial guideline for picture stories - if I go too far above that, I get asked to axe stuff because the text overrun starts breaking the picture-story page layout,) I am already well over-budget on character count by merely scratching the surface.

As for the retail vs review sample thing, I agree that reviewing from retail would be better but that cost would come right out of my own pocket and I cannot afford that unless I can get 5+ picture-story slides or 2+ review-style pages per $10 spent - unless it is something I already had (the old SurgeArrests and BX1000) or something I would have bought anyway.

 

[merikafyeah]

To answer a few questions some may have about SurgeX products and its derivatives, first off, no, they do not use MOVs. MOVs by design wear down over time from surge events and will eventually fail. SurgeX products do not use components that can wear down from surge events and cannot fail due to a surge or transient spike.

Companies like ZeroSurge, BrickWall, and Torus Power license their technologies from SurgeX, as SurgeX holds the patent for its unique surge elimination design. Note how I say surge "elimination" and not "suppression". We're talking about a whole different beast here. Cheaper knockoff products from companies that do not use the SurgeX design as a base may use MOVs and will most likely not offer the same level of protection as SurgeX's "series mode" design. SurgeX has since improved its design and is now marketing it under the term "Advanced Series Mode". SurgeX has not yet licensed this newer design afaik so all derivatives currently use the older SurgeX design from the 90s, which is not necessarily a bad thing as the design is solid, but it may not be as efficient or robust.

The following videos may help further illustrate the SurgeX design and differences with other typical surge suppressors:

SurgeX Technology Overview:
https://www.youtube.com/watch?v=79p3ysUnx_Y

SurgeX vs MOV Suppressors:
https://www.youtube.com/watch?v=RixUrc-FRcM

As shown in the second video, typical surge suppressors pollute the ground and/or neutral connections which is a huge no-no for audio equipment and other delicate electronics and only SurgeX has a viable solution for those who want real protection for their equipment.

Many people have been confused about SurgeX and similar products, as can be seen here:
http://www.avsforum.com/forum/40-oled-technology-flat-panels-general/1146963-surge-protectors-brickwall-zero-surge-furman-surgex-etc.html

Most of the other technical questions people have can be answered by contacting SurgeX, as I am not a certified technician.

 

[Daniel Sauvageau]

[quotemsg=14354975,0,775985]Companies like ZeroSurge, BrickWall, and Torus Power license their technologies from SurgeX, as SurgeX holds the patent for its unique surge elimination design. Note how I say surge "elimination" and not "suppression". We're talking about a whole different beast here.[/quotemsg]
Not that different when you read SurgeX's patents including US 7 068 487 from 2004 - the biggest difference is the use of a fancy RCD snubber (yes, I noticed the SCRs but all they do is switch in extra capacitance during surges to bring snubber voltage down further) network with three large electrolytic capacitors in place of MOVs to eat the surge energy and those tend to have finite lifespan when you charge them using 100-200A pulses. The use of series inductors to limit instantaneous peak current is every bit as applicable to RCDs as it is to MOVs - SurgeX conveniently omitted that fact in their '89 patents to make MOVs look as bad as possible.

If you put a 120µH inductor in the path of a 6kV, 8µs surge, you are effectively current-limiting it to a much more manageable 400A peak and you need something to shunt that current or otherwise you will not get any voltage drop across the inductor. Unless SurgeX has found a way to break Kirchoff's current law, that 400A coming out of the source, through the inductor and RCD network still has to return to the source through the neutral wire - the sum of all currents coming in or out of a node must be zero. There is still surge current getting shunted to neutral; the inductor is simply making it about an order of magnitude more manageable than having none - enough to make the resistor demonstration work.

 

[somebodyspecial]

http://www.brickwall.com/pages/no-failures
10yrs of 100 surges of the what IEEE considers some of the harshest environments out there, [B3 strikes] isn't bad Just a point of reference here. IF you're saying they are no different than MOV's I think I have a problem with that. If a $30 tripplite (etc) could perform like these I don't think these guys could sell their stuff for $240 and up and live long in the market. Stadiums (cowboys, yankees, carnegie hall etc) don't use this tech for nothing.

"You do not have to take our word for it. Consider the following:

IEEE (The Institute of Electrical and Electronic Engineers) states that 6000V is the largest transient that the interior of a building would experience.
IEEE defines its harshest interior surge environment as one that could experience 100 surges of 6000V, 3000A in a years time (category B3).
A new federal guideline recommends that a surge protector utilized in a harsh environment should be capable of withstanding 1000 surges of 6000V, 3000A or ten years worth of IEEE's category B3.
UL (Underwriters Laboratories) now provides a new adjunct testing service (in addition to the 1449 safety classification) that will test surge protectors to the 1000 surge, 6000V, 3000A federal protocol."

""Early in 1996, 1000 surges (at 60 second intervals) of 6000V and 3000A were applied to an off-the-shelf Series Mode Surge Protector.

There were no failures. There was no performance degradation. Let through voltage did not exceed 400V.

We still perform this testing on our equipment today."

These things can take this and live. How long would your MOV last?

http://surgex.com/aboutus.html
"100% Fail Safe Protection: For the past twelve years, SurgeX technology has never failed to protect connected equipment, due to an AC surge-related event. That’s a fact. "

So are you saying they're lying? ZERO failures is impressive if true (and they are all claiming it). You are essentially saying they'll fail just like MOV's here right?

Isn't 1000 strikes of 6000v or 3000amps every 60 secs higher than your 100-200a pulses? They hit these with 1000 of them and they lived. Doesn't this kind of blow a hole in your example? Can you show me an MOV based surge that can take this much testing an live? They don't EAT the voltage, they slow it down.

http://www.brickwall.com/pages/how-it-works
How brickwall says their units work.

http://surgex.com/library/10001_WhatisTrueSeriesMode.html
Their claims of what is different, for anyone who cares

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=P11VNT3&tab=features
APC says it can take A 6000v spike, but no claim of taking A 1000 of them.

http://espei.com/catalog/pdfs/product-sheets/ESP-SurgeX-Product-Line-STANDALONE.pdf
Let through of 0v and can take 1000+ spikes.

In this article of yours, aren't you saying they can take maybe one or two big hits and then fail? I'll take 1000 vs. 1 or 2. I used to sell tripplite/apc and I've seen a tripplite I sold, fail with one night of strikes (and they didn't cover the customers stuff either). So you'll have to forgive me if I go with the one that says it can withstand 10yrs in the the harshest environments of 100 strikes each year.

https://en.wikipedia.org/wiki/Surge_protector
More reading...There seems to be no argument MOV's don't hold a candle to these SM (series mode) units.
"These devices are not rated in joules because they operate differently from the earlier suppressors, and they do not depend on materials that inherently wear out during repeated surges."

"Because SM work on both the current rise and the voltage rise, they can safely operate in the worst surge environments."

Ok then...Not that wikipedia is the best source, just an example. You might say these have a finite lifespan, but at 1000+ B3 strikes I'd say in my area I'll be dead LONG before my surge will be. But go ahead and get the $50 APC if you'd like

"But since the SM devices do not wear out and are not required to be replaced every few years, the overall cost of ownership is much lower."

Either they are saying they are BETTER, or I'm just not picking up what this guy is putting down. DO NOT WEAR OUT is pretty clear language no?

"Surges are not diverted but actually suppressed. The inductors slow down the energy. Since the inductor in series with the circuit path slows the current spike, the peak surge energy is spread out in the time domain and harmlessly absorbed and slowly released from a capacitor bank.[31]"

They sure sound DIFFERENT to me. Slowing the current down and EATING it are two completely different things. EATING=quick death. Slowing=longer life. I could go on, but I'm thinking you should get the point by now. The OP was correct, these are a different BEAST (thus ~5-10x more expensive up front).

 

[falchard]

As a former cable technician, I hope no one buys this for the Coaxial surge protection. If it's a 15 year old design, chances are it will not properly transport the signal. Plus surge protection on coaxial should not be an issue unless the cable was improperly installed, like a hot ground.
BTW my CyberPower UPS has been going strong since 2010. Pretty happy with it, but the battery age will probably be creeping up soon.

 

[Daniel Sauvageau]

[quotemsg=14357911,0,925801]IF you're saying they are no different than MOV's I think I have a problem with that.[/quotemsg]
An RCD network is obviously not exactly the same thing as a MOV and the SurgeX snubber uses SCRs to trigger its secondary snubbers that give the SurgeX its "voltage dip" characteristic in mid-surge. But they are similar enough in function for SurgeX to choose to use the MOV symbol to represent their snubbers in their simplified schematics for prior-art-vs-invention comparisons.

[quotemsg=14357911,0,925801]So are you saying they're lying? ZERO failures is impressive if true (and they are all claiming it). You are essentially saying they'll fail just like MOV's here right?[/quotemsg]
SurgeX's patent does not state what capacitor model they use; only that they are 100-200µF 450V. I do not think there are any electrolytic caps rated for 200-400A charge current. I do not think I have seen electrolytics rated over 10A RMS. It may take thousands of cycles at such a charge current but I would expect them to fail eventually.

[quotemsg=14357911,0,925801]Isn't 1000 strikes of 6000v or 3000amps every 60 secs higher than your 100-200a pulses? They hit these with 1000 of them and they lived. Doesn't this kind of blow a hole in your example? Can you show me an MOV based surge that can take this much testing an live?[/quotemsg]
3000A is the current limit on the source but the actual output will not go that high unless the load has low enough impedance to allow it, which is exactly what the inductor is there to prevent: if you put a a 120µH inductor in series, current rise from a 6kV voltage difference gets limited to 50A/µs, which translates into about 400A peak at the end of a 8µs pulse. Split this between two MOVs, that becomes about 200A each, split four-ways and it becomes about 100A each. 20DnnnK and most equivalent MOVs are rated for 10 000 shots at 100A with less than 10% parameter deviation. The potential for a surge suppressor manufacturer to build high-endurance MOV-based designs is certainly there. Also keep in mind that 6kV is what UL deems to be the worst-case surge voltage that should be allowed to get indoors so the typical everyday surge would be nowhere near that bad and the MOVs' useful life would end up that much longer.

[quotemsg=14357911,0,925801]They sure sound DIFFERENT to me. Slowing the current down and EATING it are two completely different things. EATING=quick death. Slowing=longer life. I could go on, but I'm thinking you should get the point by now. The OP was correct, these are a different BEAST (thus ~5-10x more expensive up front).[/quotemsg]
As noted in my previous responses and alluded to in the article itself ("taking the edge off surges"), "slowing the current" by using inductors is every bit as applicable to MOV-based designs as it is to SurgeX's snubbers. Since you get no voltage drop across an inductor unless there is a current change through it, something has to eat that 50A/µs ramp for any surge suppression, elimination or whatever marketing wants to call it to occur. Without the shunt components sinking that current, whatever they might be, the small inductors become useless.

The SurgeX still needs to eat (snub) all the excess energy coming through that inductor like the MOV does. The difference is that a simple MOV cannot do anything more than follow its I-V curve as the inductor current rises while the SurgeX can switch in its discharged caps to soak up that energy when it detects a fast edge and momentarily drag the voltage down. Both will need to eat the same 400A ramp and both will need to dissipate about the same amount of energy.

Is SurgeX's design better? In most circumstances, yes. Is it worth paying 5-10X as much for? Not when everything you are going to plug into it already has tolerance to 500-600V peak due to universal input SMPS which can easily accommodate a good MOV-based suppressor's 340-400V peak clamping voltage.

 

[Daniel Sauvageau]

[quotemsg=14360027,0,137621]As a former cable technician, I hope no one buys this for the Coaxial surge protection. If it's a 15 year old design, chances are it will not properly transport the signal. Plus surge protection on coaxial should not be an issue unless the cable was improperly installed, like a hot ground.[/quotemsg]
How much have two-way splitters changed over the past 50 years? Macroscopically, they still look exactly the same and internally, they are also wired the same. The only difference is the material the ferrite core and coupling capacitors (if any) are made of with newer splitters using materials more suitable for 1GHz instead of the old powdered iron cores that could only go to something like 350MHz.

Transmission line and transformer theory has not changed in decades so there is not much of a reason to expect a major re-invention here. The layout is the same but they may have updated components inside, such as using a lower capacitance TVS.

I can think of one simple reason to use the surge protection: tying grounds so cable ground is referenced to the same ground as your expensive AV equipment. If you end up with different ground voltages between equipments for whatever reason, surges can start jumping around.

 

[falchard]

I am not overly familiar with the science behind cable signals, I just know in the last 15 years there was a jump from analog to digital. Before every 6 MHz would give you one channel that may appear as white noise if the signal is not clean enough. On the switch to digital it changed to binary so any interference made parts of the screen stop for a second. They also began increasing the channels per 6 MHz band. I think its something like 8 to 16 channels per band now. The major difference over the last 15 years is that the degree of error in detecting a 0 or 1 has gotten smaller due to pushing more information through the same 6 MHz band.
If the pass through does not hold a consistent enough signal it may cause some issues. For instance the coaxial threading material is copper in this and galvanized steel in the rest of the line, so it may not have sufficient grounding to prevent minute amounts of RF interference.

 

[mctylr]

[quotemsg=14352051,0,1736083][quotemsg=14349380,0,436284]Please find an EE to write about electronics. I'm not a professional, but even as a hobbyist I cringed at some of the lack of knowledge.[/quotemsg]

Not sure what you are cringing at since everything you said, I had already written and drawn - if you look at the simplified diagrams, you see the MOVs in shunt configuration, the inductors in series with live and neutral (ignore the MOVs with both terminals on the mains-side) and the capacitor across those L/N inductors to complete the LC filter.
[/quotemsg]

Apologies for the confusion there, I meant the series vs. shunt comparison as part of my retort to "merikafyeah;" whom I'm not certain is also "somebodyspecial."


[quotemsg=14352051,0,1736083][quotemsg=14349380,0,436284]Please find an EE to write about electronics. I'm not a professional, but even as a hobbyist I cringed at some of the lack of knowledge.[/quotemsg][/quotemsg]

My cringing was more directed at your earlier articles, where for example on:

■ Silk Road you pretty much avoid identifying the PTC thermistors
■ Juicy Lemons which outlines how your original article evolved differently than your original intentions. I'm afraid I felt that was reflected in some befuddlement in that original piece
■ Everyone Loves Stickers you point out weak translation (entertaining I admit) but don't highlight or really explain key points on the label, namely that is does have UL and CSA listings, and that as a "power bar" it is classified as a "Relocatable Power Taps" under UL 1363 (XBYS) standard, and as a "Surge Protection Device' (SPD) under UL 1449 - (VZCA)
or even explain what TVSS (Transient Voltage Surge Suppressor) means or implies - that is that the devices are only intended to suppress a short (hence transient) voltage surge (a massive) over-voltage condition. It does not mean that such surge protectors devices (SPD) can be used to regulate AC voltage from a gas or diesel generator for safe usage with electronics.
■ Speaking Marketese - You don't explain, comment, or point readers towards information about understanding the kJ (kilojoules) rating of such SPD. Is 3kJ good, adequte, and/or sufficient? -- Most consumers compare SPD based one a) price, and b) possible either blindly compare the kJ surge suppression rating, but more likely the size of the thousands of dollars guarantee as it deals with terms most people are more familiar with. Would 5 kJ unit be a better choice? Is a $1-2 dollar store SPD of sufficient quality or misplaced trust?
■ The Outlets - I'm surprised given since 2008 the NEC requirement for new homes to use tamper-resistant (TR) receptacles. I would of expected tamper resistant receptacles - which I assume requires being spring loaded or automatic - to become standard on better power bars and SPDs, even though I understand your frustration with using these spring-loaded covers can be awkward.

In summary in the first article from the PTC non-identification to speculating in public whether the copper trace may of been designed as a fuse annoyed me, but I felt there was the gigantic missed opportunity to try and clear up much of the FUD about surge protection devices was still missed in this latest article. I do believe the latest article did benefit in clarity and quality from not having the change of intention as your first piece did.

[quotemsg=14352051,0,1736083]This is a picture story for the typical THG reader; not a reference paper for EMI/SPD engineers and advanced hobbyists. With a target budget of about 750 characters per image (that's the editorial guideline for picture stories - if I go too far above that, I get asked to axe stuff because the text overrun starts breaking the picture-story page layout,) I am already well over-budget on character count by merely scratching the surface.[/quotemsg]

Okay, I understand, and I did expect something more inline with a recent reference series articles How To Choose A Motherboard: A Guide For Beginners, or How To Calibrate Your HDTV, or the very detailed Display Testing Explained: How We Test Monitors and TVs.

[quotemsg=14352051,0,1736083]As for the retail vs review sample thing, I agree that reviewing from retail would be better but that cost would come right out of my own pocket and I cannot afford that unless I can get 5+ picture-story slides or 2+ review-style pages per $10 spent - unless it is something I already had (the old SurgeArrests and BX1000) or something I would have bought anyway.[/quotemsg]

Again, that wasn't intended as a specific criticism towards yourself or this article or series, but a general observation, and a general response to rdc85's comments on reviewing manufacturer supplied samples.

 

[somebodyspecial]

[quotemsg=14364217,0,436284][quotemsg=14352051,0,1736083][quotemsg=14349380,0,436284]Please find an EE to write about electronics. I'm not a professional, but even as a hobbyist I cringed at some of the lack of knowledge.[/quotemsg]

Not sure what you are cringing at since everything you said, I had already written and drawn - if you look at the simplified diagrams, you see the MOVs in shunt configuration, the inductors in series with live and neutral (ignore the MOVs with both terminals on the mains-side) and the capacitor across those L/N inductors to complete the LC filter.
[/quotemsg]

Apologies for the confusion there, I meant the series vs. shunt comparison as part of my retort to "merikafyeah;" whom I'm not certain is also "somebodyspecial."
[/quotemsg]

It's comic you see two posts that agree, and immediately think conspiracy. Surely toms could tell you our IP's are different, which cable provider we use etc etc etc

Not sure who the other guy/gal is (nor do I care, unimportant), but his/her general point is correct. But since that comment (both I guess) was sort of slammed, I decided to add a little more detail for the person in their defense (and they did it themselves also). There is a difference in quality or the ones with MOV's would be advertising they can take 1000 strikes in their spec sheets also, instead of a SINGLE strike. Period.