A question for an EE - Surge protector joule ratings - how much is enough

[westom]

Well you can't say this thread isn't lively

It would be boring if he had any facts and numbers. "Kill the messenger" is always a lively event.

 

[jneutron]

It would be boring if he had any facts and numbers. "Kill the messenger" is always a lively event.

Begging for attention again, eh? Over the last 5 years, you've ignored all numbers.

Look up faraday's law of induction. Then calculate the induction at 10 meters given 200 kiloamps and a rise time of 1 uSec. (for those who read, this is the generic return stroke). The leader is in the 30 kiloamp range.

Go for it... I'll wait.

jn

 

[jneutron]

Then, calculate the energy dissipation in joules, for a cascaded SPD system where the primary whole house unit receives 10 kilojoules over 100 uSec, it clamps at 400 volts, and a branch SPD 100 feet away on a 15 ampere circuit with a 330 volt clamp.

For simplicity, assume the clamps are hard, it makes the integral easier to calculate.

Well???

This is simple first year engineering. Something you've never had.

jn

 

[jneutron]

Then, calculate the induction caused by a 200 kiloamp return stroke with a rise time of 1 uSec 10 meters away from the house of dimensions 45 foot by 20 feet, where the AC lines are in the wall furthest from the strike, and the cable runs up the wall closest to the strike, 20 feet closer. Assume the geometric loop split occurs in the basement, and the cable goes to the HT sytem via the attic, and that the floors are 9 foot height.

Well, where do you start??

This is all trivial engineering math by the way.

jn

 

[Speedskater]

'westom'

Member "jneutron's" day job is at one of the huge US east coast scientific laboratories. The magnitude of the voltages and currents that he deals with every day, boggles the imagination. Over the years he has co-authored several several scientific papers on super-conductors and the like.

 

[jneutron]

Then, calculate the energy dissipation in joules, for a cascaded SPD system where the primary whole house unit receives 10 kilojoules over 100 uSec, it clamps at 400 volts, and a branch SPD 100 feet away on a 15 ampere circuit with a 330 volt clamp.

For simplicity, assume the clamps are hard, it makes the integral easier to calculate.
jn

For those interested:

This is an example of cascaded coordination, where a whole house SPD is in the load panel, and a secondary one is at the equipment being protected.

A line transient coming in off the street tries to raise the voltage from the 120 volt sine to some ungodly value, like a kilovolt or more. It could be something as simple as your neighbor's 2 ton AC compressor unit shutting off, and both of you are 200 or 300 feet from the pole transformer.

Your whole house SPD clamps the spike to a level of 400 volts per design, and it is assumed that it is capable of withstanding the energy being pushed into it because it is clamping.

So the important thing here is, the event happens for 100 uSec, and for that length of time, the line voltage is 400 volts.

At the far end of the 100 foot long 15 amp branch circuit, there is an SPD with a clamp voltage of 330 volts. So, when the 400 volts at the panel try to raise the branch voltage, it clamps 70 volts lower at the device than the value at the panel. Because the romex is #14awg, it has 2.5 ohms per kilofoot, or .5 ohms total for 2 lengths of 100 feet.

The current that occurs in the branch circuit is therefore 70 volts of drop over .5 ohms of resistance, or 140 amps.

140 amps times 330 volts is 46,200 watts. Because the event lasts 100 microseconds, or 100/1000000 (one ten thousandth of a second), the total joules absorbed by the point of use SPD is the power in watts times the length of time. The branch spd absorbs 4.6 joules. (edit: I originally said 46, it's not.)

Contrast that against the 10 kilojoules I mentioned for the whole house unit. Without the whole house unit, the point of use SPD would have to clamp the entire spike by itself

This is the beauty of cascaded coordination. The whole house unit can be extremely robust, but you only need one. The point of use SPD's can be far less robust, because they will not see the huge energy dissipations of an unprotected line.

My other example asks for deriving the induced voltage caused by a near strike with a loop of wire. The point of use SPD, when it is a multiport design, combats this induced voltage by combining all the grounds of the equipment with the wire grounds in the very local area, thereby eliminating the induction voltage spike.

This is why I recommend both a whole house and point of use multiport SPD's, as the whole house cannot stop induction into wire loops in the house.

jn

ps. In the last 10 years, I have lost two devices to induction transients. The house across the street had a very tall evergreen tree (Blue spruce is what I'm guessing it is) hit with a bolt at it's top. It is about 50 feet from my house. I lost a DVD player and a smoke alarm, both on the second floor of the house, one in front, one in back.

The DVD player had it's AC power come in conduit on one side of the house, and the cable feed came up the opposite side, through the attic, then down to the DVD. That loop is what bit the device.
The smoke detector had the same, but it connected down to the basement where there was another detector, all the detectors are wired to alarm everywhere in the event one goes off. So it was bitten by induction as well.

No other devices were wired with such a wide loop. The master bedroom I ran all the wires personally during a reno, and made sure there were no large loops between the cable feed and the AC power distribution. This time, I was the windshield....not the bug.

 

[jneutron]

Then calculate the induction at 10 meters given 200 kiloamps and a rise time of 1 uSec. (for those who read, this is the generic return stroke).

From ampere's law, the magnetic field associated with a straight current is:

B = Mu[sub]zero[/sub] times current / 2 pi times distance.

For a 200 kiloamp current, at ten meters the field is .004 Tesla.

The rise time of 1 uSec (or 10e-6 seconds) means the magnetic field is changing at a rate of .004 Tesla/10e-6 seconds.

4000 Tesla per second.

Faraday's law of induction states that the EMF (induced voltage) is equal to the negative rate of change of the total magnetic flux within an area.

So at ten meters from the bolt, the rate of change of the field is 4000 Tesla/sec.

For a 1 meter square loop ten meters from the bolt, the EMF will be 4 kilovolts.

For the house example, the loop area is 21 square meters. The lowest field will be 13 meters from the bolt a value of 3000 volts per square meter induced, so there will be a slight drop in total induction for the integrated loop. Bracketed between 84 kilovolts and 63 kilovolts.

Remember, when a loop is closed, the current induced will buck the magnetic field of the strike, so that will further reduce the voltage. And, flashover occurs at roughly 70 kilovolts per inch. A quarter inch gap in the loop will flash at about 17 kilovolts, then remain ionized for the balance of the strike duration.

An I phone is what, .1 meter by .05? about .005 meters square? .005 times 4000 is 20 volts. Any shielding whatsoever in the Iphone will reduce that an order of magnitude if not more, so portable devices are really not that sensitive to strikes 10 meters away. zero meters, of course that's different. All bets are off if you drop the darn thing when the bolt startles you..

jn

 

[jneutron]

Panamax M4300-PM Power Manager Review | Audioholics

This is infuriating. Here is a Panamax M4300-PM Power Manager that audioholics has reviewed. It's obvious from this thread that the position of surge protection is not to invest in tiny boxes but to find a whole house surge protector. Fine, I can understand that.

But.....

Why would an audioholics review promote the use of this device as a 'buffer' between the outlet and electronics plugged into it? In other words, why are they advocating a single device such as this as a surge protector to protect your gear from lightning strikes and the like and NOT advocate a whole house surge protector as well? ...." More importantly, however, it gives you something between your expensive AV equipment and the wall, so that if you ever encounter lightning or any other power surge event, something other than that new LCD or plasma display can take the hit. " You know if the true stance on equipment protection is not a single device but a whole house surge protector why would a website that is devoted to pursuing the truth in video and audio support this devices' mild form of surge protection? It's buffering capability?

As you are the OP, you deserve a response.

The unit reviewed has several advantages.

1. It has inputs and outputs for several types of signal cables. That allows it to connect all the grounds at that one point, so that lightning cannot induce voltages between units and between the cable from street. It also allows plugging in all three prong devices to it. This is called a multiport SPD, in that it has multiple "ports" for the other cables.
2. It seems to have transient protection as well. I didn't go through the article, but typically these will have some MOV based clamping devices to prevent immediate destruction via transients. I used to work at the largest TVSS manufacturer on the planet (Transient Voltage Surge Suppressor), and for line cord based stuff, 800 volts was defined as the minimum allowed design voltage for switchmode supplies and transient handling.
3. It disconnects when line surges show up. This is where the line voltage goes well over normal, and if it really goes up, it would toast normal MOV suppressors. Disconnecting, if done fast enough, could prevent this. I do not know how fast this would have to happen, but I would assume half a line cycle tops.
4. If a real hit occurs, such as a direct strike, I am not sure if this unit is the end-all. But then again, in all residential units, a direct strike cannot be controlled anyway. Large facilities control direct strikes by diverting all the bolt current around the structure like a bird cage (faraday cage is a closer description). The top of the empire state building for example, is what, a thousand feet from earth yet little happens within the building during a strike. That is because it is conducted over the outside of the building by lots and lots of independent current paths (building columns). That really reduces the magnetic field inside the building.

Using a whole house in conjunction with this unit is not a bad thing of course. With a robust whole house unit, this device will see no more than approximately 450 volt transients, which it looks quite capable of handling.

As a standalone, it will indeed clamp bad transients, and in the event of an AC line surge, it will disconnect the line. To me, the best thing is the multiport function, as that is where I personally have had historical failures due to induced voltage of near strikes.

While you indicate "this thread" as indicative of what to use, remember...westom really doesn't understand surge protection, so you need to read the actual engineering stuff and decide if you want to go for it.

Me, at home I do not use surge suppressors, multiport SPD's, nor even a whole house unit. My home HT/audio system really is not worth the expense, and I've taken care of the normal loop trapping induction pathways when I installed all the wiring prior to insulation and drywall. Yes, I lost two components that were connected with legacy wires from the older construction, but I replaced the dvd for 30 bucks, and the smoke alarm for about 40. Ten years, so far so good. If I invested in significant dollars with my equipment, I would not run it without a whole house and more importantly, I would absolutely invest in a multiport SPD. The reviewed one seems good and has features I like. ( I do not, as a general rule, recommend specific pieces of equipment, as it is my desire to remain impartial).

At work, another story. Combinations of devices on the 13Kv lines, devices on the 480 3 phase panels and transformers, more devices on the 208 three phase panels (300 of them), devices within the rack mount equipment (about 5,500 pieces of electronics), and a distributed grounding scheme which meets code, uses #2/0 bare copper, daisies from 5 central hubs daisied from 1, with isolation breaks in the primary machine every 166 meters.

jn

 

[westom]

Look up faraday's law of induction. Then calculate the induction at 10 meters given 200 kiloamps and a rise time of 1 uSec. (for those who read, this is the generic return stroke). The leader is in the 30 kiloamp range.

This is something you have never done. Give numbers. But then you forget to make any numeric conclusions from those numbers. An honest post would have calculated the numbers from Faraday’s law of induction. You don’t for one simple reason. You cannot, Knowledge of Faraday's law means you also did the calculations.

Professional papers have provided examples of those numbers. Not for a short 10 meter antenna. They used longer i(ie 30 meter) antennas that even better couple to fields from a nearby lightning strike. A nearby lightning strike (maybe 30,000 amps) induced a few thousands volts on that antenna lead.

Put an NE-2 neon glow lamp (ie from a lighted wall switch) on that antenna lead. Then thousands of volts drop to tens of volts conducted by a neon lamp. Milliamps conducted by a neon bulb causes thousands of volts to drop to near zero. Because current induced on that long wire antenna is trivial. Energy content induced on an antenna (designed to maximize field effects) is trivial. These are the numbers you did not provide because you do not know how to calculate a Faraday effect. You have hyped a myth to create a fear.

Why does a nearby lighting strike not damage all nearby computers, mobile phones, and automobile radios? Those radios are designed to maximize fields on its sensitive RF transistor. Why are these not damaged by induced fields from a nearby lighting strike? Because even the most sensitive transistor in radios are protected by something equivalent to a neon glow lamp. To make what would otherwise be thousands of volts into near zero volts. Protection of electronics from induced fields has always been that easy.

If your claims about induced surges were accurate, then every car radio, wrist watch, and cell phone in a parking lot are destroyed by every nearby lightning strike. In reality, none are. Because fields generated by nearby 30,000 amps currents create surges of near zero energy. Destructive surge means a direct connection from that lightning bolt.

Unlike you, I did this stuff. A direct lightning strike to a lightning rod meant maybe 20,000 amps was flowing down a wire to earth. Four feet away from that 20,000 amps was an IBM PC. According to hyped fears, the PC was damaged. Reality. That PC did not even blink. All other nearby electronics also worked uninterrupted. Because energy content created by an induced 30,000 amp current is near zero. Made irrelevant by protection routinely inside every appliance.

You post a paragraph of wild speculation based on numbers you do not even understand. Numbers that do not support a valid conclusion. Reality takes many paragraphs to explain. Induced surges creating speculated damage is a bogus myth promoted when fears create wild speculation. You cannot even do your own Faraday calculation.

 

[westom]

... a branch SPD 100 feet away on a 15 ampere circuit with a 330 volt clamp.

You have no idea what longitudinal and transverse mode currents are. That current approaching a branch SPD is moving in the same direction on any or all wires. Obviously you did not know that. Maybe 100 amps approaching an SPD either means a same 5000 volts on all SPD wires (therefore no volts across an MOV). Or that current creates 5000 volts on the MOV's black wire side. And 4670 volts on other AC wires. Therefore 5000 volts and 4670 volts are also incoming to any nearby appliance. While an MOV only has 330 volts across it, thousands of volts created by the same current are confronting 'protected' appliances.

You have posted a classic myth often promoted when electrical knowledge is minimal. Provided are the other numbers you did not know because you did not do this stuff.

If you knew how protectors work, then you also knew that an MOV is only 330 volts when a surge is tinier - well below the MOV's maximum specs. When the same MOV is conducting a major surge, then its voltage is closer to 900 volts. Anyone who reads MOV datasheets and applications notes would know that. You do not read datasheet charts. Those charts are read when designing this stuff. You also did not learn from MOV manufacturer's application notes.

An incoming surge current hunts for earth ground. Adjacent protector manufacturers do not even claim to protect from that type of surge. Obvious had you learned simple concepts such as longitudinal and transverse currents. An adjacent MOV protector only protects from one. Those currents are typically made irrelevant by protection already inside appliances. Even GFCIs, clocks, dimmer switches, and the door bell are so robust as to make irrelevant that type surge current. Had you known that, then a '330 volts across an MOV' claim would have explained why that same current also created maybe 5000 volts on attached appliances. But that means learning a first year EE concept.

Demonstrated is why you do not post numbers. Your numbers expose myths behind your accusations. You do not even take those numbers into a numeric conclusion (ie the Faraday law). That requires fundamental electrical knowledge. Even first year concepts such as longitudinal and transverse currents were unknown to you. MOV datasheets were not read. A speculated 330 volts on a protector means maybe 5000 volts on the black wire and 4670 volts on the green and white wire. Where is the protection?

Fundamental concepts for effective and less expensive protection have been understood for over 100 years. Protection means one knows where hundreds of thousands of joules dissipate. Why do you never discuss that energy? Power strip manufacturers best avoid reality by not discussing it. Since their products do not claim to protect from the typically destructive surge current. Protection is always about how that current connects to and how that energy dissipates in earth. You again avoid those relevant numbers and concepts.

 

[markw]

Why does this famous clip come to mind while reading this thread?

 

[jneutron]

This is something you have never done. Give numbers. But then you forget to make any numeric conclusions from those numbers. An honest post would have calculated the numbers from Faraday’s law of induction. You don’t for one simple reason. You cannot, Knowledge of Faraday's law means you also did the calculations.

This thread is just sooooo cool.. You post incredibly stupid statements saying I didn't do something right under the posts where I did it. again.

The reason I've not asked the owners of this forum to admonish you in any way, is because you provide entertainment to an otherwise dull topic. Everybody waits on edge for your next rant, trying to guess what nonsense you'll come up with next. And you don't disappoint.

I've detailed amperes law, faradays law, and explained a bit about Lenz's law, and I actually kept the math at a 3rd or 4th grade level so you would understand. You didn't, but that's not my failing.

Me personally, enjoy watching your gyrations, your rants, your utterly nonsensical methods of posting incongruent and meaningless culls from the work of others.... Your Looney Tunes understanding of surges (where the lightning bolt chases Marvin the Martian up and down stairwells, eventually knocking in the door to the closet Marvin is hiding in to zap him.)

Your value here is really just for laughs and to bump the thread. It's fun for me, and it actually allows me to expound a bit on what really goes on in the world of transients and surges..

jn

ps.. I tried to read your posts in full. What a bunch of drivel.

It is interesting that you are learning some new words however. Now you actually use the word "Faraday", albeit incorrectly.

Knowing your schtick as I do, and your level of understanding, it does not pay to trash every single one of your bogus statements. There is not enough time in the day to trash the 90% of your posts which are incorrect. But it would be fun even if it is a waste of time explaining it to you.

PPS. I would like everybody to know.... I do NOT pay westom any money to play a really goofus devils advocate. That is his own doing.

 

[jneutron]

Why does this famous clip come to mind while reading this thread?

Ummm, because it's apropos?

Tis only a flesh wound...

jn

 

[jneutron]

BTW, if anybody has questions about what I've posted, or even what w-dude has posted erroneously, please feel free to ask. I've no problem detailing what I've described.

While speedskater has alluded to my writing style has being a really weird mix of things, I find I cannot disagree..

Cheers,

John

 

[jneutron]

Professional papers have provided examples of those numbers. Not for a short 10 meter antenna. They used longer i(ie 30 meter) antennas that even better couple to fields from a nearby lightning strike. A nearby lightning strike (maybe 30,000 amps) induced a few thousands volts on that antenna lead.

Had you a degree in electrical engineering, as I have, you would know that faraday's law of induction cannot be applied to a dipole antenna of any length.

Since you do not, you make glaring errors.

Unlike you, I did this stuff.

You haven't made one statement that would lead anyone to believe that you have any work experience whatsoever, nevermind in the field of engineering.

I do love the way you bandy about words you do not understand.

Keep going, I like the occasional good laugh..

jn

 

[jneutron]

Everyone with any encounter knows complete well that the first job in security is shunting the volts motivated present to floor as quick as possible.

Actually, not quite.

It is to prevent a potential rise which can damage equipment or endanger human lives. In many cases, it requires engineering to provide a conductive path which does not radiate sufficient time varying magnetic field to destroy anything with a conductive loop.

In some cases, it is to re-direct the path.

If only it were as simple as you state..

jn

 

[jinjuku]

JNeutron, you are the only person that I would willing pay for high priced cables

 

[Darkwing_duck]

As you are the OP, you deserve a response.

The unit reviewed has several advantages.

1. It has inputs and outputs for several types of signal cables. That allows it to connect all the grounds at that one point, so that lightning cannot induce voltages between units and between the cable from street. It also allows plugging in all three prong devices to it. This is called a multiport SPD, in that it has multiple "ports" for the other cables.
2. It seems to have transient protection as well. I didn't go through the article, but typically these will have some MOV based clamping devices to prevent immediate destruction via transients. I used to work at the largest TVSS manufacturer on the planet (Transient Voltage Surge Suppressor), and for line cord based stuff, 800 volts was defined as the minimum allowed design voltage for switchmode supplies and transient handling.
3. It disconnects when line surges show up. This is where the line voltage goes well over normal, and if it really goes up, it would toast normal MOV suppressors. Disconnecting, if done fast enough, could prevent this. I do not know how fast this would have to happen, but I would assume half a line cycle tops.
4. If a real hit occurs, such as a direct strike, I am not sure if this unit is the end-all. But then again, in all residential units, a direct strike cannot be controlled anyway. Large facilities control direct strikes by diverting all the bolt current around the structure like a bird cage (faraday cage is a closer description). The top of the empire state building for example, is what, a thousand feet from earth yet little happens within the building during a strike. That is because it is conducted over the outside of the building by lots and lots of independent current paths (building columns). That really reduces the magnetic field inside the building.

Using a whole house in conjunction with this unit is not a bad thing of course. With a robust whole house unit, this device will see no more than approximately 450 volt transients, which it looks quite capable of handling.

As a standalone, it will indeed clamp bad transients, and in the event of an AC line surge, it will disconnect the line. To me, the best thing is the multiport function, as that is where I personally have had historical failures due to induced voltage of near strikes.

While you indicate "this thread" as indicative of what to use, remember...westom really doesn't understand surge protection, so you need to read the actual engineering stuff and decide if you want to go for it.

Me, at home I do not use surge suppressors, multiport SPD's, nor even a whole house unit. My home HT/audio system really is not worth the expense, and I've taken care of the normal loop trapping induction pathways when I installed all the wiring prior to insulation and drywall. Yes, I lost two components that were connected with legacy wires from the older construction, but I replaced the dvd for 30 bucks, and the smoke alarm for about 40. Ten years, so far so good. If I invested in significant dollars with my equipment, I would not run it without a whole house and more importantly, I would absolutely invest in a multiport SPD. The reviewed one seems good and has features I like. ( I do not, as a general rule, recommend specific pieces of equipment, as it is my desire to remain impartial).

At work, another story. Combinations of devices on the 13Kv lines, devices on the 480 3 phase panels and transformers, more devices on the 208 three phase panels (300 of them), devices within the rack mount equipment (about 5,500 pieces of electronics), and a distributed grounding scheme which meets code, uses #2/0 bare copper, daisies from 5 central hubs daisied from 1, with isolation breaks in the primary machine every 166 meters.

jn

I gave up on this website/forum after I felt i was receiving very little/poor help from some members ( TBH I felt westom wasn't giving me a direct yes/no answer the way you just did for a reason ) and even the main guys running the site ( I emailed gene a few times with my questions and didn't even get a hello back ) but YOU and this reply was like vindication for being ignored.

Thanks man, appreciate the help. I managed to pick out some very crucial points - whole house surge protection/multiport SPDs aka surge protects with multiple 3 prong inlets ( right? ) and perhaps routing the conduit in the house with your specific technique about the loops ( maybe its too late for me to do this one )

I like your black n white yes/no answer. By far the best reply I've received from anyone on this topic.

 

[Darkwing_duck]

As you are the OP, you deserve a response.


jn

jn,

What about Line conditioners in Surge Protectors and stand alone Line Conditioners

and last question, is it safe to daisy chain one surge protector into another surge protector for the assumed benefit of doubling joule ratings ( i.e. 1500 joules in each bar x 2 = 3000 joule of protection) and line conditioning ( i.e. -30db of reduction in line noise from one and another -30db from the other protector = -60 db in total of noise reduction)

Thats pretty much all the questions I have on this topic which is just so poorly handled on the web so thanks a bunch for giving some insight

ps: I think i figured out the daisy chain question....It should be okay to daisy chain surge protectors as the number of outlets used doesn't overload the circuit as for the question on surge protection, Ive come to the conclusion that in the event of a surge, the first surge protector will absorb its pre-determined voltage and then the residual voltage spike NOT absorbed from the first power bar will be passed to the second ( or daisy chained ) surge protector and that remaining residual voltage spike will be absorbed by the pre-destined voltage absorbtion capabilities of that power bar.

I assume the same logical flow would apply to the line conditioning mechanism....any "un-clean" power passed through the first surge bar to the second daisy chained bar will then cleanse the remaining "dirty" power up to its designated engineered limits, etc , etc

Can I take this information and apply it in practice at home then?

 

[westom]

Ive come to the conclusion that in the event of a surge, the first surge protector will absorb its pre-determined voltage and then the residual voltage spike NOT absorbed from the first power bar will be passed to the second ( or daisy chained ) surge protector and that remaining residual voltage spike will be absorbed by the pre-destined voltage absorbtion capabilities of that power bar.

I assume the same logical flow would apply to the line conditioning mechanism....

Electricity does not work that way. The surge is a current source. That means current flowing through a first protector is, at the same time, also flowing through a second protector, and through any 'at risk' appliance. You have assumed protectors work by blocking or absorbing a surge. Protectors that would somehow absorb surges do not claim to protect from destructive surges.

How much voltage on each protector? Voltage increases on each protector that tries to stop a surge. Voltage can increase as much as necessary to blow through that protector. Because surges are a current source; not a voltage source. And because current flows simultaneously through everything in that path. A current incoming is simultaneously current also outgoing to the second protector and adjacent appliance.

Current flows through everything in that path. Much later one or many devices in that path are damaged. Nothing blocks, absorbs, or cleans that surge current.

Nothing stops a surge. Surge protectors (rated at near zero, hundreds of joules) only absorb tiny surges that are harmlessly absorbed by electronics. So tiny as to be considered noise. Sometimes that surge is consumed by an appliance to power its semiconductors. Those near zero surges are irrelevant.

Protection is about where hundreds of thousands of joules are harmlessly absorb. No protector or line conditioner does that.

Solution in facilities that cannot have damage is the 'whole house' solution. Then hundreds of thousands of joules dissipate harmlessly outside. Then superior protection and line conditioning already inside appliances is not overwhelmed. Once that surge current is inside, then nothing can avert a destrucxtive hunt for earth via appliances. Nothing.

Protectors do not cleanse anything. Best protection on cable is a hardwire from that cable to single point earth ground. Other utility services (telephone, AC electric) cannot connect directly to earth. So a protector does what a hardwire does better; connect low impedance (ie 'less than 10 feet') to what absorbs hundreds of thousands of joules. Single point earth ground absorbs (stops) a surge. Effective protectors are only connecting devices to earth; do not absorb or 'clean' surges.

Protection is always about where hundreds of thousands of joules harmlessly dissipate: single point earth ground. An 'art'. An 'art' that means "yes or no" answers do not exist.

Nothing inside a house successfully stops, blocks, or absorbs a destructive surge. Smaller surges are made irrelevant by superior protection already inside appliances. Protection from larger and destructive surges (hundreds of thousands of joules) must make a low impedance (ie 'less than 10 foot') connection to single point earth ground. Because only single point earth ground can harmlessly absorbs that energy - does what you believe a protector should do.

Daisy chain protectors are only as good as one device in that chain. Protection does not get better with more protectors. But protection does get better with each layer. Earth ground defines each 'secondary' and 'primary' protection layer. Protection is always about where hundreds of thousands of joules harmlessly dissipate. How many joules does that protector or line conditioner absorb? Near zero.