Power Strip Surge Protectors - Example comparisons

[c627627]

Discussions on this topic are usually overly complicated for average user. But there's not that many numbers on specs you are really supposed to look at?

Let's just say you're at the store and have two or three in front of you with prices that make you think how do I know if one is perhaps overkill, and how do I calculate what I need for computer or TV or stereo equipment or both or all three? Should we use them with other household appliances, refrigerators or whatnot? There is a lot of misinformation out there. It shouldn't be that complicated.

Equipment examples are overclocked top of the line computer system with the usual printer, scanner, etc. accessories ; 50 inch Plasma with usual accessories like DVR, DVD, VHS; and a nice stereo system.

Not everything needs to go on the same strip, but can you look at these examples and post quick opinions for Computer/TV/Stereo equipment examples?

Thank you.


Other than cord length, there are really only two categories that I can see where they differ, how important are the differences between:
AC suppression joule rating 1080 vs 2160 vs 2520
Maximum Surge Amps 72000 vs 144000 vs 156000

Spoiler

Spoiler

Spoiler

 

[fornoob]

Specs don't give every pieces of information you may need to choose a PSU, that is why review are appreciated too: it gives you an "anatomical" view of the PSU.
An example: it is seldom said in the specs what kind of technology it is using for the surge protector, you have to look at it yourself... inside the PSU ^^
It can have heavy consequences depending on the kind of PSU and use you are planning to do (high voltage, high current, high frequency, ...)

But you are completely right: there are some numbers that can be checked through specs.

Two things mainly can kill your PSU: overvoltage and overcurrent (overheat).

Why overvoltage?

Imagine that you can run 1 hour in a row at a constant speed of 10 km/h.
Your trainer asks you to run faster: at a constant speed of 13 km/h.

Do you think you will last one hour? ^^
It would be even worse if 15 km/h or 20 km/h were asked.

The higher the difference between your "standard" voltage and your instantaneous voltage, the lower your life espectancy.

To avoid overvoltage, there are surge protector in the PSU. Basically, it converts voltage into current and heat, passed a certain threshold.

The voltage threshold is called clamping voltage or let-through voltage.
It means that under this threshold, your surge protector does... nothing. It only goes conductive passed the clamping voltage.
So, intuitively, we think that the lower the clamping voltage is , the better.
It isn't completely true: a low clamping voltage gives you better protection, but if the surge protector is activated too often, its life expectancy decreases.

So low clamping voltage = higher protection but lower life expectancy.

The AC suppression Joule rating corresponds to the amount of energy (heat) the components of the surge protector can absorb in one single event without failure.

This parameter is really misleading and quite complicated to deal with...
The thing is that energy can be dissipated either in the protective component (often MOV for metal oxyde varistor) or in the ground.
It is good for life expectancy of the MOV to let the ground absord a part of the energy. That is why an high Joule rating is not necessarly the best thing.
BUT, energy spikes can be very large and a too low Joule rating can be seen as an undersized protection...
It is the couple of clamping voltage and Joule rating that is interesting: a lower clamping voltage with the same Joule rating means that you will dissipate more power elsewhere than in the MOV.
An higher let through voltage permits higher Joule rating but let more current go through to device to be protected...

Really often, Joule ratings are increased by connecting several MOVs in parallel. The problem is that MOVs are non linear and don't have the same sensitivity. Then, each MOV won't see the same amount of current, so overuse of one component, conducting to premature failure.
What is important is the MOV with the lowest clamping voltage -> only it determines your effective energy absorption.

To conclude with the Joule Rating, be really carefull with it: if you see a PSU with twice the JR of an other PSU, then consider the parameter as misleading: there are 2 MOV instead of 1 and it isn't exactly the best thing.

Maximum Surge Amps (I prefer Inrush current ^^):
It is the maximum, instantaneous input current a device see when first turned on. It can go really high (hundred times your max allowable current in normal conditions) and can damage the PSU.
The lower the inrush current is, the better it is for your component.
But I don't know if the number given in the specs is your real inrush current (what it sees) or the inrush current it can handle (what it can survive)... I will let others explain this part since both possible definitions can lead to opposite conclusions

 

[fornoob]

To calculate what you need for your computer isn't complicated: you simply add the TDP (thermal dissipation power) of your components and you consider that you don't want to use more than 80% of your PSU's max power in the worst case.

So, let's take an example:

CPU ~100W (slightly overclocked )
GPU ~200W
MB ~ 15W
SSD ~5W
HDD ~10W
OD ~10W

Power needed ~340W = 0.8 Power of the PSU needed -> PSU's power ~340/0.8 ~425W

If you have overclocked your CPU/ GPU really high (or plan to do it), then increase the power (it is not linear, the higher you increase the frequency, the more your power consumption increases).
If you have more than one GPU, then add the TDPs.

TDP are the worst case scenario in power consumption: you almost never reach them.

For the sound/ video display, it almost always have an independent power supply and don't have to be taken in account for the calculation of your computer power.

 

[c627627]

So.............................. do you see the three example Surge Suppressors I posted in post #1? Other than cord length, there are really only two categories that I can see where they differ, looking at the differences between:
AC suppression joule rating 1080 vs 2160 vs 2520
Maximum Surge Amps 72000 vs 144000 vs 156000


If they were priced drastically differently, is the most expensive one not worth it?

 

[fornoob]

Since they have the same clamping voltage (150V) and a Joule rating > 1K, it is not worth it to buy the most expansive.
The only remaining difference is the UL rating, but 330V is the most standard protection level and is more than enough for a common PC-user.

Based on what is written in the specs (as I said, it isn't often enough to truly judge a PSU), the second one in your list is already fine, so no reason to pay more.

 

[Bobnova]

My thoughts on all of the above:

High joule rating comes from either more MOVs / TVS Diodes wired in parallel, or larger MOVs / TVS Diodes (I'm going to call everything MOVs henceforce, but not all surge protection comes from a MOV, TVS Diodes are superior in almost every way). The different between the 1080joule unit and the others is likely how many are wired in parallel. The difference between the larger two may well simply be how large the individual elements are.

When faced with a surge the MOV(s) begin conducting and dump it to ground. There is a voltage drop across the MOV, that voltage drop causes heat buildup, which eventually kills the MOV. There isn't anything to be done about this, other than using an array of MOVs to spread that heat out. This runs into one of the difficulties with MOVs, they are not precision devices. They're made, essentially, out of bazillions of tiny diodes all glued together at random. This is one of the places that a TVS Diode is superior, it is simply a pair of Zenar diodes facing each other, this are precision devices, and hence can be easily matched to others.

The higher current rating is a result of how many / how large the MOVs are as well, more MOVs can dump more current without catastrophic failure.

As to the question of what you actually need, for a PC with a good PSU any of them will likely be fine, good PSUs have a TVS Diode, fuse, and filter circuit and are able to stand up to some surges on their own. Adding a second layer of protection is still a good idea though!
Other devices may or may not have surge suppression built in, I'd like to think that anything expensive would, but I kind of doubt it.

In conclusion, the primary difference between the units is how many MOVs they have inside, and how high the MOVs are rated current wise. All of them likely have a basic transient filter, as it helps in withstanding surges as well.

 

[westom]

If they were priced drastically differently, is the most expensive one not worth it?

One from WalMart may cost $10. An electrically similar product (a $4 power strip with ten cent protector parts) can also sell at $90. Because so many view price - not the actual product - to buy a profit center.

Two completley different devices are called surge protectors. One adjacent to an appliance can only block or absorb that surge. How do 2 cm parts inside a power strip stop what three miles of sky could not? It doesn't. It only claims to protect from lesser surges already made irrelevant by protection inside appliances.

How does its 2500 joules (actually only 800 and never more than 1700 joules) absorb a surge that is hundreds of thousands of joules? It doesn't. It only claims to protect from lesser surges already made irrelevant by protection inside appliances.

1700 or 2500 joules devices are similar (tiny) since destructive surges are hundreds of thousands of joules.

Another and very different device also called a surge protector. This is the only solution always found in every facility that cannot have damage. Typically located in the breaker box where it can make what is most important: a low impedance (ie 'less than 10 foot') connection to earth. If a TV needs protection, then so does the dishwasher, GFCIs, all digital clocks, dimmer switches, and furnace. What most needs protection during a surge? Smoke detectors. Only a 'whole house' protector does that protection. And costs about $1 per protected appliance.

A destructive surge is a current that seeks earth. Only you make that choice. Either a surge finds earth inside and destructively via appliances (with or without that adjacent protector). Or you connect a surge harmlessly to earth BEFORE it even enters the building.

This is not complex. And is how it was done over 100 years ago. Effective protection means a surge connects to earth without entering the building. Two completely different devices with the same name. Only one does protection from typically destructive transients.

A lightning rod connects that electrical current to earth so that currrent need not find earth, destructively, via the structure. A 'whole house' protector connects that electrical current to earth so that current need not find earth, destructively, via appliances. That simple. Lightning rods and protectors work by connecting to earth ground.

Spend less money for the superior solution. More responsible companies provide a 'whole house' solution including General Electric, ABB, Intermatic, Ditek, Leviton, Square D, Syscon, and Siemens ... to name but a few. A Cutler-Hammer solution sold in Lowes and Home Depot for less than $50. Superior protection for everything - at less than $1 per protected appliance. Because it makes a short connection to what does the protection - single point earth ground.

When hundreds of thousand of joules are harmlessly absorbed outside, then potentially destructive surges do no damage. A protector is only as effective as its earth ground. The other completely different device (also called a protector) does not have and will not discuss earthing.

 

[Bobnova]

Here we go again. How about some citations this time Westom?
Real ones, not "Go read spec sheet X" (which I did, and did not contain what you were saying...).

 

[westom]

Here we go again. How about some citations this time Westom?

This is how others make it overly complex. The engineer who did this stuff simplified it for the layman. Even second grade science explains how protection works. Ben Franklin - earth a surge. Lightning is an electrical current that will find earth ground. Connect that current to earth so that it does not go inside a building. It was always that simple. More responsible companies provide those superior and less expensive solutions.

Now a more complex discussion from professionals - even though it is still all about earthing and a protector connected short (ie 'less than 10 feet') to that earth ground. From the IEEE Red Book

In actual practice, lightning protection is achieve by the process of interception of lightning produced surges, diverting them to ground, and by altering their associated wave shapes.

From IEEE Emerald Book

It is important to ensure that low-impedance grounding and bonding connections exist among the telephone and data equipment, the ac power system's electrical safety-groundingsystem, and the building grounding electrode system.

From the IEEE Green Book

Lightning cannot be prevented; it can only be intercepted or diverted to a path which will, if well designed and constructed, not result in damage. Even this means is not positive, providing only 99.5-99.9% protection. ...
Still, a 99.5% protection level will reduce the incidence of direct strokes from one stroke per 30 years ... to one stroke per 6000 years ...

From Polyphasers legendary application notes entitled "Shielded Data Cables and Protectors" describing why damage occurred:

Lightning strikes somewhere across the street close to the below grade West cable vault. ... The first line of defense is the telco protection panel, but the panel must be connected to a low resistance / inductance ground. There was no adequate ground available in the telephone room.

From ProtectionGroup's FAQ entitled "Grounding and Bonding Questions"

Lead lengths must be as short and direct as possible. A wire’s inductance increases over length, causing a delay in the protector’s response; subsequently the let through voltage is increased.

More citations and a link to even more from dshoaf in "What computer components or electronics have you lost due to electrical storms?" posted 2 Aug 2011 at
http://forums.anandtech.com/showpost.php?p=32077212&postcount=86

Another from Polyphaser entitle How to earth a Ham Station - engineering paper:

The ideal plan is a single point ground with no sneak paths. Sneak paths are loops that allow lightning current to flow into the equipment room.

From psihq.com is an introduction to grounding:

Ten years ago it would have been rare for anyone to talk about the importance of low resistance grounding and bonding except where mainframe computer systems, telecommunications equipment or military installations were being discussed. Today, we live in a world controlled by microprocessors so low resistance grounding is now critical and is a popular topic of conversation.

The electrical grounding system in most facilities is the electrical service entrance ground. In the past it was often "OK" to just meet the minimum requirements of the National Electrical Code (NEC). Today, the requirements of the NEC should only be the starting point for grounding systems and bonding.

From a paper by Dr Kenneth Schneide:

Conceptually, lightning protection devices are switches to ground. Once a threatening surge is detected, a lightning protection device grounds the incoming signal connection point of the equipment being protected. Thus, redirecting the threatening surge on a path-of-least resistance (impedance) to ground where it is absorbed.

Any lightning protection device must be composed of two "subsystems," a switch which is essentially some type of switching circuitry and a good ground connection-to allow dissipation of the surge energy. The switch, of course, dominates the design and the cost. Yet, the need for a good ground connection can not be emphasized enough. Computer equipment has been damaged by lightning, not because of the absence of a protection device, but because inadequate attention was paid to grounding the device properly.

But then all this was introduced to everyone in elementary school science. More citations: From LightningSafety.com

3. Bonding
Without proper bonding, all other elements of the LPs are useless. Bonding of all metallic conductors in a dispatch facility assures everything is at equal potential. When lightning strikes, all grounded equipment will rise and fall equipotentially. This eliminates the unequal voltages in separate sensitive signal and data systems. Bonding should connect all conductors to the same "Mother Earth." A partial listing includes the following: tower legs, adjacent fences, ice bridges, incoming coaxial cables, cable trays, cabinets and racks, signal reference grids, halo grounds, the proliferation of conduits carrying various AC power and low-voltage DC current conductors. Not convinced bonding is important? Check out NEC 250.90 through 250.106 for more details.

4. Grounding
Low-resistance grounding provides an efficient destination for the "lightning beast." If your site soils are composed of sand or rock, they are resistive, not conductive. If your surrounding soils are of clay or dirt, they may be conductive. "Good grounds" are achieved by volumetric efficiencies. We recommend buried bare 4/0 copper wire – the so called ring electrode or ring ground. ... NEC 250 describes other grounding designs such as rods, plates, water pipes (beware of plastic pipes underground), metal frame of buildings, and concrete-encased electrodes. Choose your grounding design based upon localized conditions and the amount of available real estate at your location. NEC 250.56 suggests a target earth resistivity number of 25 ohms. Lower is better.

From Electrical Code vs. Good RF Grounding by K9KJM on November 22, 2003

Those who say "nothing will withstand a direct lightning strike" are very misinformed. My towers take direct lightning hits most every big storm. So do most all tall commercial towers. With NO damage!

Those old wives tales of damage are for the most part over 50 year old tales of woe from improperly grounded/ protected stations. (Or more recent stories of stations that were grounded with 50 year old technology) Power companies learned many years ago that number 6 copper wire was heavy enough to withstand over 98 percent of direct lightning strikes. So number six copper became the size to use for lightning protection

Emergency response centers in Orange County FL suffered repeated damage from lightning. So they eliminated the problem by fixing the only item that does all surge protection. The earthing.
http://www.copper.org/applications/electrical/pq/casestudy/florida911.html

ABB video demonstrates how struck high voltage towers earth transients:
"... with the prerequisite however that the tower is adequately earthed."
http://www05.abb.com/global/scot/sc...ffae47234f7c125736e0021458c/$File/pexlink.wmv

Another case study demonstrates how surge damage to a Nebraska radio station was eliminated. They upgraded what does protection - the earthing:
http://www.copper.org/applications/electrical/pq/casestudy/nebraska.html

Why do professionals discuss earthing so much. And say so little about those plug-in protectors? They must install protection - not enrich the less responsible companies. Provided were products from the more responsible companies - names that any guy would know for quality. In each case, a 'whole house' protector, installed even by any informed layman, means best possible protection for about $1 per protected appliance.

How many more citations do you want? Or we simply use what we learned from Ben Franklin and elementary school science to identify the protectors that actually make protection possible. In every case, it has a short wire (ie 'less than 10 foot' connection) to single point earth ground.

 

[Bobnova]

I'm not even sure what you're arguing with those copy/pastes (which is not correct citation, as a sidenote). As to why they don't discuss them, I'd guess that it's because you skipped those lines. That's why correct citation includes a link or at least a page number. Then I/we can go read the rest of the thing and see what else it says. Careful copy/pasting can make almost anything support almost anything.

If you'd like to play the "why" game, why does (nearly?) every single high end PSU in existence have surge suppression built in?

 

[RollingThunder]

Westom banned from thread until further notice.

 

[bud--]

Excellent information on surges and surge protection is at:
http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf
- "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits" published by the IEEE in 2005 (the IEEE is a major organization of electrical and electronic engineers).
And also:
http://www.eeel.nist.gov/817/pubs/spd-anthology/files/Surges happen!.pdf
- "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home" published by the US National Institute of Standards and Technology in 2001

The IEEE surge guide is aimed at people with some technical background.

Two completley different devices are called surge protectors. One adjacent to an appliance can only block or absorb that surge. How do 2 cm parts inside a power strip stop what three miles of sky could not? It doesn't.

Of course not. Plug-in protectors do not work by "blocking" or "stopping" or "absorbing" surges. (Both service panel and plug-in protectors do absorb some energy in the process of protecting.)

Westom believes that surge protection must directly earth a surge. Since plug-in protectors are not well earthed he believes they can not possibly work.

The IEEE surge guide explains how plug-in protectors work (starting page 30). It is not primarily by earthing a surge. They limit the voltage from each wire to the ground at the protector. The voltage between the wires going to the protected equipment is safe for the protected equipment. Since the explanation does not fit westoms belief system he ignores it.

It only claims to protect from lesser surges already made irrelevant by protection inside appliances.

Nonsense.

Appliances may or may not have surge protection built in. Not likely you can find any that has thousands of joules protection.

How does its 2500 joules (actually only 800 and never more than 1700 joules) absorb a surge that is hundreds of thousands of joules? It doesn't.

Of course not. Thousands of joules can not make it through a branch circuit.

The author of the NIST surge guide investigated how much energy might be absorbed in a MOV in a plug-in protector. Branch circuits were 10M and longer, and the surge on incoming power wires was up to 10,000A . (That is the maximum that has any reasonable probability of occurring and is based on a 100,000A strike to a utility pole adjacent to the house in typical urban overhead distribution.) The maximum energy at the MOV was a surprisingly small 35 joules. In 13 of 15 cases it was 1 joule or less. (This paper is probably still available on the internet if anyone wants to read it.) Compare that to thousands of joules for the protectors in the OP's post. High ratings mean the protector will have a long life and is likely to never fail. That is why some manufacturers can have protected equipment warranties.

One reason the energy is so low is if the voltage from service panel busbars to the enclosure reaches about 6,000V there is arc-over. After the arc is established the voltage is hundreds of volts. Since the enclosure is connected to the earthing system that dumps most of the energy from a strong surge to earth.

***When using a plug-in protector all interconnected equipment needs to be connected to the same protector. External connections, like coax also must go through the protector.

The high surge current ratings in the OP's post just go along with the high joule ratings. There about zero probability of even getting those surge currents at the service panel.

If a TV needs protection, then so does the dishwasher, GFCIs, all digital clocks, dimmer switches, and furnace.

The NIST surge guide suggests that most equipment damage is from high voltage between power and cable/phone/similar wires

More responsible companies provide a 'whole house' solution including General Electric, ABB, Intermatic, Ditek, Leviton, Square D, Syscon, and Siemens ... to name but a few.

All these "responsible companies" but SquareD make plug-in protectors and say they are effective.

SquareD says for their "best" service panel protector "electronic equipment may need additional protection by installing plug-in [protectors] at the point of use."

For real science read the IEEE and NIST surge guides. Both have excellent information on surges and surge protection. Both say plug-in protectors are effective.

Most of the many quotes in westom's other post are about earthing. Everyone is in favor of earthing electrical systems. Some quotes misrepresent the views of the authors.

In a previous thread moderator hokiealumnus told westom:
"With two more posts-sans-reference, after staff discussion, we're done here. westom, in the future, back up what you're saying with references or do not post. You have been asked numerous times yet fail to do so, thus your posts are to most people are meaningless. If you do not wish to do that, that's fine; just don't enter the discussion."

NONE of westoms quotes say anything about plug-in protectors. This is at least the second time westom has compulsively posted his misinformation here since the edict from hokiealumnus.

 

[c627627]

I don't know what happened here and how an average user is supposed to participate in this discussion but if I am looking at those three items at the store from the example above... I do not understand whether the most expensive item is worth the extra expense or if the 1080 joule item is OK.

 

[RollingThunder]

Bud,

You're outta here too. You're not banned from this thread (yet) because you need to see this reply. We are not going to have you and Westom use OC Forums as your battleground for trolling each other. If either of you start a new thread to continue, you're history.

Best Regards,

RT

 

[fornoob]

I don't know what happened here and how an average user is supposed to participate in this discussion but if I am looking at those three items at the store from the example above... I do not understand whether the most expensive item is worth the extra expense or if the 1080 joule item is OK.

I don't know too what happened to your thread, this kind of things might happen on the internet

Anyway, bobnova's answer complete/clarify my own: both give you the "technical explanation" and the conclusion imho is 1080 Joule item is OK

Please forgive us to be sometimes (often? ^^') unclear for the common user: electronic is sometimes really sophisticated and the basics can be sometimes really long and painful to give (so imagine if you had to give it again at every single post for every single guy)

Letting people google it themselves does NOT seem to be the ideal solution to me since there are a LOT of missinformation ...( we got a splendid example )

Maybe a sticky would be usefull to reexplain the basics, but it gonna be long and it gonna be hard (even if most things have already been explained in stickies)

PS: @ Bobnova, yes, I didn't mention the zenar diode because of what I've just said above: speaking of this to someone that may not know what it is requires that I explain everything and it can be too long for a forum post ^^'

 

[c627627]

Whatever is going on here, a simpler explanation is needed, there is no way an average consumer can process what was said in this thread.

 

[Bobnova]

Those two chase each other around the internet trolling each other. Or maybe they're actually the same person, I don't know.

Fornoob I think you are I are pretty much saying the same thing, from different directions

 

[Culbrelai]

Sooo... on this topic...

How good is this

http://www.newegg.com/Product/Product.aspx?Item=N82E16812107131

to protect a Corsair AX1200w system (complete specs are the In Utero section in my sig) a printer, network switch, speaker system, occasional laptop, 200w heater

Been eying it for ages because of its huge number of outlets. Never commited. Funny, hard to commit to something that's $27, but easy to spend $160, $780... Sigh.

 

[larrymoencurly]

Apparently other electrical engineers think plug-in surge protectors help, even when the circuit breaker box already contains a whole house surge protector.

The last time Consumer Reports tested surge protectors was Jan, 2000, and 15 out of the 20 products gave very good surge protection, including half the products that CR judged to be of inferior design quality. Apparently they judged design quality according to the joule capacity of the surge protection and any AC/RF line filter. I don't know if the line filter helped with the protection or simply meant the rest of the product was built better. You can usually do a rough check of that filter by plugging the surge protector and computer into the same AC outlet as a laser printer or vacuum cleaner. Have the computer idle at a DOS prompt, preferrably with the hard disks disconnected, and turn the laser or vacuum on and off. If the computer glitches, then the protector doesn't have line filter containing both capacitors and chokes. But if the computer doesn't glitch, it could simply mean the computer power supply's built-in line filter is darn good. Some line filters are just a single capacitor wired across the AC lines (may be touted as an RF filter), as is the one in my old Belkin (I can see through its clear case), which rated among the worst in CR's tests. It also failed the laser printer/vacuum cleaner test, as did two completely different designs of Belkin 350VA battery backup power supplies. OTOH every APC backup has passed that test and does have a choke-capacitor filter.

 

[Bobnova]

Every PSU that isn't junk has a complete line filter in it these days.

As to that surge protector, I have no idea.
I guess maybe I should build a test device and start testing 'em.