Why whole house surge protectors are not enough

I'd like to second your callout regarding surge suppression and LAN protection from your blog.  A few months ago we had lightning hit a tree that was just 15 feet from our electrical entrance with is underground. It took out 2 TVs, 2 UPSs, Router, 3 Switches, BlueSound Node, and the Inverter for my solar system, One of the UPSs actually smoked!  One TV would not even power on, the HDMI ports and LAN port did not work on the other.  I suspect the static charge traveling through the LAN as taking our the2 TVs and the LAN equipment. Strangely enough, the cable modem was not damaged.  I have since added lightning arrestors to the cable and LAN networks. 

I should have added, that I had a whole house surge suppressor in place on the outside panel also.

I’d like to second your callout regarding surge suppression and LAN protection from your blog. A few months ago we had lightning hit a tree that was just 15 feet from our electrical entrance with is underground.

@upshift Sorry to hear that but really interesting.

I want to warn you not to use grounding Ethernet arrestors inside your home. Use those, if any, outside or as close to that edge. Inside stick to isolators. The most recent thinking I’ve seen is that grounding Ethernet cables during a surge just allows a high current surge to form through MORE devices when otherwise you wouldn’t have one. Better to isolate the gear and let lightning find a path through a single device and it’s power cable than to form a long circuit and let it take out even more devices downstream. So far during the worst of the lightning I’ve only lost a cable modem, which wasn’t mine anyway. 😁

Alternatively, use fiber converters to air-gap your gear.

After installing my whole-house suppressor lightning took out a laptop. It was the only PC in my home that was plugged in but NOT on a surge strip.

The same way audiophiles are kind of ridiculous with having too much gear to play music, we also have a lot more Ethernet devices hooked up than the average person, though hard core gamers are close.  For many Americans who have Internet access Wifi is the only connection they use and lightning is not the same problem than for someone like me who has a dozen items hooked up via copper networking cables.

@erik_squires  Thanks for the update, I didn't realize that.  I am using a grounding type arrestor, I'll check out the isolators.  I am using optical between my router and my audio equipment, mainly to replace a 50' run of ethernet cable.  Have a plan in place to do the same throughout the house.  Would be nice to see optical connections supported on more equipment like modems and routers but realize that it may be a limited market.

I am using optical between my router and my audio equipment, mainly to replace a 50' run of ethernet cable

A solid idea in terms of minimizing surge risk at least.  The longer the Ethernet cable, the more the antenna effect it can have.

I want to point out that lightning entering the Ethernet system without actually coming through the cable provider’s wiring is an edge case, but exactly the sort of problem I’m worried about.

That is, my guess is that 90% of home network surges happen from the copper that goes from outside to inside of the home, and the remaining are from induced (EM pulse) currents from INSIDE the home Ethernet wiring.

The longer a run of Ethernet the better it may pick up a lightning surge. From what I’ve read this danger starts around 30’ long runs.

Once the wiring is involved the next question is how will it find a path to ground? That path is often through a power supply somewhere. Once that gap is broken through everything in the way will fry as the surge arcs over. In these cases shorting (MOV) based surge protectors become co-conspirators by offering a low-volrage gap to ground.

Network isolators work by increasing the necessary arc-over voltage by 4kV at a time. This forces the surge current to look for a path with less resistance to ground which hopefully involves fewer devices.

And this is the thinking I've read lately.  You may not stop the surge current, but you can reduce the total number of connected devices involved.  If you fry a cheap switch instead of your switch, TV, streamer, PC, etc. it's a good thing.

Erik,

Given that I don't have to deal with lightning where I live, and power is actually underground so cars don't hit poles either.

But I would rather take my chances and buy new gear if damaged than compromise sound quality.

Jerry

@carlsbad2

Do whatever you’d like so long as you remain informed. :)

Personally, I don’t even want to LIFT the equipment off my rack, much less deal with insurance or replacements. :) Also, I run some nice PC’s here and don’t want them to fry with my data on them, same for my music collection.

Here on the SC coast I have underground power in my neighborhood but that doesn’t stop the power from glitching due to transformer and other power issues elsewhere. My surge protectors or UPS has to intervene about 3x a year even without lightning or known vehicular assaults on my gear. :)

As for the rest of the home, I have a lot of permanently attached devices besides major appliances such as automated lights, fire alarms and GFCI outlets.  I met a man a month ago or so whose home was struck and he lost his entire outdoor AC units.  No idea if a WHSP would have saved him, but just evidence that we are prone to that kind of damage here.

I have a Siemens that monitors the voltage from the breaker it’s good for around $6 years and the LEDs if they turn red it’s time to change or stopped a electrical surge 

it was under $300. And saved my $3500 OLED tvs and computers 

to me it was$$ well spent from my Audio I have a custom one my  AudioEngineer friend built for me as well as my 4 wire AWG 10 dedicated line with a common ground as well as a insulated isolated ground and it’s own dedicated Copper buzz bar and ground . Even with a audio computer I get very quiet black back grounds .

@audioman58  I have the same brand, but mine stop blinking and an audible alarm goes off.

Even so, their high clamping voltage is why I supplement those with point of use surge protectors.

I am looking for a  dedicated unit for my audio ,not quite sure maybe the                AQ Niagra 5000.

@erik_squires   +1

Clamping voltage increases with clamping current.  It can be 250Vpeak (line to neutral) at 1mA, but it will more than double at few thousand of amperes.  Surge current will be reduced by inductance of long power line, but not with close hit,  House wiring inductive reactance in combination with secondary protector will reduce peak voltage a bit more  (smaller voltage differential = lower surge current = lower clamping voltage) .  Strong secondary protection will always be better, but there is no excuse for not using any.

Eric mentioned in linked article, that huge number of joules is not needed.  If we assume huge 10kA surge current lasting 10us and 600V clamping voltage it will produce energy of 10kA x 600V x 10us = 60 joules.  Event is likely longer than 10us, more like 100us, but main energy peak is within 10us.  100 joule protector ought to do any job.  Even small, one outlet, Belkin absorber ($9 on Amazon) is listed at 885 joules total - 295 joules in each of 3 modes - much more than needed.  

Surge protection and isolation are intended to protect you from something from somewhere else getting to the stuff you want to protect.  I designed in Whole House protection at the main panel of my home and that protects two ways - between the two 110V phases that add together to provide 220V to HVAC, stoves, and other large loads like big swimming pool pumps, etc. 

That does NOTHING to protect you from the start-up spike put on the line on a single 110V phase when you turn on a vacuum cleaner, table saw, refrigerator or other significant motor load anywhere inside the perimeter protection of a WHSP unit. Your HVAC Air Conditioner will often put a spike on BOTH poles because those units usually run on 220 V. the worst culprit is not the fans inside or out, but the compressor motor in the outdoor part of your system.  If you look in your circuit breaker box, you will usually find several double-wide breakers with a handle that links both sides together.  That will be something that uses 220V and is probably a big load that can noticeably affect your whole house. 

Although some of your devices may have their own universal power adapters that will output the desired voltage to the attached equipment despite the incoming voltage, a large but purely resistive load like electric heat kicking on will drop your line voltage enough so your other equipment may still notice the effect and not be running at optimum unless you have a buck/boost AVR (automatic voltage regulation) unit like a good UPS between that big load and your sensitive devices.  Just don't get an inexpensive unit that puts out anything other than pure sine wave power or you will be creating more pollution on the power line than you are isolating your stuff from.  Some units even run you on batteries full time and just use the house power to charge the batteries. 

Just make sure you do not run different parts of your system on multiple sources or you may have serious grounding issues. This also means that you want to avoid running some devices from the "surge only" outlets on a UPS and other devices on the "battery backup" outlets of the same UPS, or worse, from another UPS' battery supported outlets.  Having a variety of ground potentials across your system can have some weird and undesired effects.  This is where you want someone who can design and put together a good system isolation and protection scheme for you, not just someone who can meet local codes for safety. 

Any decent sized motor load (or a poorly designed one) can also put a sharp spike on the power line when it turns on or off that can cause even more havoc. Transients are NOT your friend and are more likely to be regularly attacking you from within your home than the less likely but occasionally more devastating external hits.  You want to get the best possible sound from your investment, AND protect the devices that give it to you.

I happen to use a combination of Monster Power and PanaMax line conditioner / surge suppressor devices that isolate each outlet optimally for the type of interference the connected devices are most susceptible to.  There are better and newer devices out there now, but these have worked well for me.  

Something I did not expect, was a hit one of my customers took recently when lightning came in on the shield wire of his fiber internet connection and took out about a dozen devices across his network.  The UPS isolated the power, but routers, modems, network switches and even network cards in workstations got fried.  The ISP had decided they did not want their ethernet cable grounded through the UPS, and they had not put a ground tie on the fiber cable before it went to their fiber-to-ethernet conversion box, so they replaced just about everything they had on site.  Not grounding their cable at the point of entry to the building was as egregious an error as not installing a whole house surge suppression box at your main power panel.   Electricity is like water - it will flow wherever it is easy to get to.  Just because the fiber isolates the data signal from EMI does not mean that the cable shield, which is there for mechanical protection as well as tensile strength, cannot carry a surge onto your premises.  

@audioman58 

Is this the Seimens that you have? 

Siemens FS140 Whole House Surge Protection.

It's the one I have. I've read it's the best whole house one available. Unsure of its clamping voltage...I had a Richard Gray 1200S at my stereo rack but pulled it as it limits transient voltage peaks to my amps which effects the music quality and went whole house protection. . 

@kijanki

Eric mentioned in linked article, that huge number of joules is not needed.

Your math isn’t wrong, but I was referring to surge strips (not necessarily a strip, but not a whole house unit). We don’t need joules for series mode protection. It’s a parallel mode thing which I don’t recommend in a strip.

For in-panel protectors, which are parallel (and the only one’s available), they publish surge current instead of joules but the effect is the same. Repeated surge current wears those MOVs down.

Of course, surge protectors are a lot like air bags. No guarantee you’ll survive, no guarantee they’ll ever even be needed but still the math says cars with air bags are statistically safer than cars without them.

That does NOTHING to protect you from the start-up spike put on the line on a single 110V phase when you turn on a vacuum cleaner, table saw, refrigerator or other significant motor load anywhere inside the perimeter protection of a WHSP unit.

I’m not sure this is completely true. As I understand it, the limiting factors are the clamping voltage of the WHSP, as well as the inductance in the line in between the surge source and the WHSP.

It IS true that the best surge strips (again not necessarily a strip, could be a rackable device) like Furman and Tripp Lite have lower clamping voltage and can reduce the surge effect at the TV, for instance, especially if the vacuum and the TV are on the same line.

PS - Given that all panel mounted surge protectors have about the same clamping voltage, I prefer the ones that mount as breakers. This minimizes the wiring and I hope minimizes the impedance, helping the surge protector to lower the surge voltage. Plus I think they are easier to install/remove. Right now I’m using a Siemens BoltShield, but previously had a Square-D panel and did the same.

I installed a Siemens whole house surge protector, and my gear is all plugged into n Emotiva CMX-6, which I am not sure provides surge protection. The amp is plugged into the wall which is a direct line to the breaker box. What do people recommend for surge protection that does not affect your audio quality? Also, the common recommendation is to plug your amp directly into the wall, are they better at dealing with surges or just worth the risk for the audio benefits?
 

What do people recommend for surge protection that does not affect your audio quality?

Furman with LiFT and SMP has never let me down. Also provides exellent noise filtering.

Emotiva CMX-6, which I am not sure provides surge protection.

Based on specs it does not. Based on images it may have some MOVs in there but it’s not passed UL or ETL testing. MOVs may just be thrown in to help the units overall reliability as many devices have, like PC power supplies, etc..

Also, the common recommendation is to plug your amp directly into the wall, are they better at dealing with surges or just worth the risk for the audio benefits?

I’d go the other way. I’ve never had anything but positive listening effects from using a Furman, therefore I always use them.

I personally don’t think the idea that all surge protectors/conditioners are current limiting and your amp is better directly to the wall. I can see this being true for many though.

As others have pointed out though, this really depends on where you live. If you are in Florida with gear you don’t want to replace, always surge protect it.

I know some people who have never lost gear due to power problems. OTOH, I have and when I moved in here there was a surge protector still attached to the wall which had obvious scorch marks. Clearly this is an area prone to lightning strikes.

It's not all about lightning either.  When I worked in an area covered by PG&E we lost several PC power supplies over the course of a couple of days.  Each time we could smell the MOV.  In another job we lost two floors worth of surge strips over a week due to PG&E switching problems.

As others have pointed out though, this really depends on where you live. If you are in Florida with gear you don’t want to replace, always surge protect it.

I'll vouch for Florida. :-(

@erik_squires 

Furman with LiFT and SMP has never let me down. Also provides excellent noise filtering.

Thanks Erik. Any models from Furman in particular that you recommend? Elite? Reference? Is Power Factor a worthwhile feature?

@zlone

Furman makes dozens of models for the pro and home use, from actual strips, rack mount and the Elite like home equipment like units. The features I know are important for noise and surge are LiFT (linear filtering), SMP (series mode surge protection) and EVS (extreme voltage shutdown). The latter will protect you from long term over voltages which are not necessarily surges. Like 90V or 140V AC. The unit will shutdown until corrected. In SC I’ve had this trigger at least 2x.

Apparently they go in and out of stock from Amazon and Sweetwater so it's worth checking in repeatedly if there's a particular model you have in mind.  The cheapest is the strip, which has LiFT and SMP but not EVS.

The rest are convenience features. I don’t think power factor matters that much, but the Elite units have add-ons like switched outlets which are great if you use a HT processor or preamp with a trigger but your amp doesn’t have one.

I use an Elite after a unit with VR (voltage regulation). Not that I need the VR feature here like I did in California (more PG&E problems) but I have it so I might as well use it.

Erik - 

If the spike your equipment encounters is coming from the same branch circuit feeding it (say a wonky vacuum cleaner in the next room), the spike will probably get to your components before it is snubbed by the WHSP back at the service entrance panel. It can be tough to explain that to the cleaning service.  BTW, my WHSP was a Square-D that I installed when putting an addition on my house back in 1997.  A big, clunky 7" cube I mounted next to the SE panel, but I never lost equipment to a surge, and that is a lot of service years.  

On the topic of MOV's - they absorb surges until they can't, then they pop. If the surge is a long one or a big one, there may be enough of it left to still do some damage beyond where the MOV USED TO BE, and if it is a tree branch shorting between phases or worse - to a higher voltage circuit, the MOV may now be just a couple of leads with an air-gap between them.  

The VR feature you mention can be quite valuable, although it may not be a big deal with all solid state equipment because SS runs at low voltages internally, and a swing of 20-30V on the line may end up being quite low once it gets past the step-down circuitry in the device. Even so, the dielectric stress, across the tiny dimensions within the semiconductor chips can still be impressive.  OTOH, with tube equipment, especially older units that lack VR in the device, when the line voltage is stepped up for the tubes themselves, that swing is magnified and is more likely to impact the sonics and life of the tube.  When the unit was designed and tubes cost $5 from your corner TV shop, that was not the concern it can be today.  Probably most people have had a "brown-out" at one time or another caused by a tree branch shorting a power line to ground in a storm.  Worse is when a higher voltage distribution line gets in contact with the low voltage feed to your home and raises the voltage to your place by a couple orders of magnitude. I had that happen to a customer and the utility company got to replace a bunch of stuff for them. Hardware can be replaced, but not so easy to rebuild what is on your media server. 

It is an uncommon step to take, but having a device (or simply a single connection to unplug and air-gap your sensitive stuff from the outside world) can go a long way to protecting you.  Keep in mind that you should also disconnect the cable feed to your cable modem and protect the power feed to EVERY point on your network.  A surge or non-standard voltage can come in through ANY point that is not protected and will continue until it is snubbed or it literally burns out the circuitry  --  be it a semiconductor, capacitor, or even a trace on a circuit board - an effect that is usually terminal for the device.   Unfortunately, a good spike can often turn the diodes in your power supply rectifier bridge into fuses, and they seldom just clip in.

I need a new refrigerator and a lightning strike would be a great way to get rid of it and an excuse to buy a new one. I like the idea about a surge suppressor at the electric panel, don’t know at what point it triggers but it seems somewhat helpful.

quality Power switches with surge protection are a real smart thing to do for miscellaneous electrical av Devices. A better power conditioner to manage noise may have some value too

If you have a large electrical storm rolling through, probably a good idea to unplug your amplifiers and components.

I guess having them turned off while being plugged in still doesn’t protect them. Happily the refrigerator will remain on waiting for lightning to destroy it and then I get a new one. Yeah.

I work with 3 retired Power Company employees, they say that whole house surge protecters are a joke and that they don't work. The company makes it so hard to file a claim, they they almost never have to pay. These are not linemen, but management.

@emergingsoul

If you have a large electrical storm rolling through, probably a good idea to unplug your amplifiers and components.

And I do but honestly I can’t be here or be aware of all of them in advance.

@mfinch

I work with 3 retired Power Company employees, they say that whole house surge protecters are a joke and that they don’t work. The company makes it so hard to file a claim, they they almost never have to pay. These are not linemen, but management.

The fine print in the warranty make filing a claim very difficult unless there is visible proof of a surge, which there often is not, or at least not one most of us could detect. Honestly I never really think of the claimed damage coverage when I buy new units. I focus on the technology and what I’m protecting.

If they sold the WHSP as protecting the TV then yeah, those things wouldn't work.

True, some devices work much better than others, so caveat emptor!

If the spike your equipment encounters is coming from the same branch circuit feeding it (say a wonky vacuum cleaner in the next room), the spike will probably get to your components before it is snubbed by the WHSP back at the service entrance panel. It can be tough to explain that to the cleaning service.

@knittersspouse 

It's true that with wire distance the ability to snub a surge via a short to ground or neutral decreases, but the function does occur.  The further the surge occured and the closer it was to say your TV the less effective a panel protector can be, but there are many branch circuits in the modern home, so having a panel unit to prevent a surge on circuit 1 from making it to circuits 2 through 30 is a good thing.

Erik - 

I totally agree.  I speak from the hard experience where the contractor originally building my home ran out of positions in the SE panel and rather than put in breakers with two circuits per box position or add a secondary panel, they just put the last 4 rooms on the same circuit.  Running the toaster and the garage door opener at the same time always popped the breaker. 

When I redesigned the home, I put in a new main SE panel that was the max allowed by the local utility and then added several subpanels throughout the house.  With well-marked and dedicated circuits available, it becomes very easy to isolate my gear when desirable. 

If the stud walls are still open, it is trivial to run separate circuits for your power amp and your lower-power devices.  I also got a deal on some cable so I ran 1/0 aluminum from the main panel to the subs, so there was minimal drop to each of the 60A panels. By running some #8 cable for the power amp back to the subpanel, that gives a fairly stiff source for the amp to draw from, and compared to the cost of the designer cables used between the wall socket and the devices, the extra in-wall cable cost was almost trivial. 

 #8 has twice the max allowable ampacity of the #12 that is almost universally used for residential outlet circuits, so when the amps ask for power, the in-wall wiring can provide it, potentially adding some punch to your music.  You just have to be careful to get #8 copper, not aluminum to get the full benefit because aluminum is used for the larger wire sizes because it becomes much cheaper, but the conductivity is somewhat less.  When you get up to sizes like the 1/0, those are almost always aluminum, and at that ampacity, the droop caused by the draw of your amp is minimal.

Anyone care to explain how a vaccum clear, or anythig inside a home, can cause a surge?  Surges always come from outside the home.

Jerry

Mfinch - 

You may be right that it is hard to get the utility to pay for a new WHSP box, but my goal is to protect my audio equipment investment, and if I can just replace a couple of hundred bucks worth of surge protection and still have my sound system, I call that a win! 

Trouble is, not many folks rig up their WHSP box with full temporary isolation so they can take it out of circuit and test it to see if it still works after you think it has taken a hit.  I'm "old school" and although in-circuit testing can be done, I feel more comfortable when testing just the device, unaffected by anything else. 

In general, the components that provide the surge protection DO degrade over time from the many small hits they will inevitably receive, and so should be tested or replaced once or twice a decade, or more often if your area might indicate it is needed (Florida or similar?).

@erik_squires Thanks for your thoughtful and detailed response.  If I lived where there was lightning, I'd be full in on the best surge protection available for everything excep my audio system....I'd probably just unplug my Regenerator before each storm....I know, PITA but as you know, I don't even like the degradation caused by fuses. 

I'd probably come up with some inexpensive equipment to use when lightning is in the area.  

Difficult problem you have and I feel for you.

thanks,

Jerry 

I use isolation transformers for all my audio gear, and all the A/V. Maybe that's why my 2009 Kuro Plasma is still working - and working well enough to make the 4K upgrade unattractive.

And thanks for the thread, Eric. A real public service.

@terry9  Isolation transformers have a lot of inductance, they act a little like series mode protectors. :)

Anyone care to explain how a vaccum clear, or anythig inside a home, can cause a surge? Surges always come from outside the home.

@carlsbad2 Depends on how you classify them. Some statistics say 80% or more come from inside, especially whenever inductive loads (i.e. big motors) start or stop. Of course, this includes very small surges we might expect equipment to shrug off. They tend to be small, but may accumulate.

Anyone who has ever heard a thump through their stereo when a vacuum, ceiling fan, AC or hair dryer has turned on or off has literally heard a surge.

Awww, thanks @terry9 

@carlsbad2

Sorry I didn’t really answer your question. As I understand it, the most common cause of a surge inside the home is when a large inductive load (motor) is turned off. The magnetic field has inertia and until it collapses is present and the motor tries to feed that energy back into the system.

This is the best description I've found:

...However, because you have current flowing in an inductor at the time of turn off there will be a transient voltage produced. Much of this voltage will occur across the power switch contacts. There maybe some very short transient rise in voltage on the supply wiring. Could be several thousand volts next to the switch and diminish as you move further from vacuum connection point. ...

https://forums.mikeholt.com/threads/can-a-vacuum-cleaner-cause-a-surge.60537/

From an important textbook:

"... it is not possible to turn off the current (to an inductor) suddenly, because that would imply an infinite voltage across the inductor’s terminals. What happens is that the voltage rises abruptly and keeps rising until it forces current to flow. ... in a case like this ... (20 VDC supply) it may go to 1000 V before the switch contact "blows over". "

"Art of Electronics 3rd Edition", Horowitz and Hill, page 38.

Erik, thanks for this thread! This brand was recommended as the very best by an electrician recommended from a reputable audio dealer:

https://transientprotectiondesign.com/products/residential/breaker-panels/breaker-panel-surge-protection/

Any comments on this brand? They are pricey at $1400 but have lifetime warranty and made in US. They have a few pdfs showing complex protection for the home. By putting it in the panel and behind a pair of 30A breakers, I assume that the idea is that the MOVs will be just slightly removed from the signal path and so interfere with that wave less during normal operation and have less detriment to sound quality.

How are we to understand Maximum Limited Voltage in this context? I'm looking at model TK-TTLP-1S240-FL with MLV ratings as follows:

2kV,67A - 36V, 6kV; 3kA - 590V; and 20kV, 10kA - 970V. I think this means for an impulse of less than 2kV and 67A, the clamping voltage will be about 120+36=156V.

I agree that a panel installed protector does nothing for induced EMF from a nearby strike, but I had a strike 20 years ago that took out the speaker and amp channel that were closest to it but not the other channel. I assume that was due to induced EMF in the speaker wire or even voice coils. Point is, if lightning strikes really close, all kinds of problems may occur including on the ground leg.

Does anyone have an opinion on these? https://ep2000.com/products/home-protection-products/premium-surge-protection-filter/?v=e75edac1b83f

We installed the Leviton unit and also use additional surge protection. Also our audio ecosystem is on a dedicated circuit with additional filtration and grounding. 

https://www.homedepot.com/p/Leviton-120-240-120-Volt-Hi-Leg-Split-Phase-Enhanced-Noise-Filtering-Module-Surge-Protective-Panel-Gray-42412-DS3/302084835#overlay

@nagel  I don't know of any SPDs in panel that activate below 600V due to reliability/safety issues.  That is, they can't use MOV's with lower voltages because they could activate too often.  For this reason almost all SPD makers for panels have about the same clamping voltage.

I think the Maximum Limited voltage is AFTER the MOV has activated.  It goes up with more circuit resistance to ground.  

In other words, you could see a 600 V or higher at the AC line before the MOV kicks in. This is why downstream strips which can safely clamp ~ 200V can be so helpful.  Not to mention, any series filtering will slow the pulse down so the protector can activate.

So, MOVs are not perfect, or instant.  They live in two states, denial and confusion.

Hah!

I mean, on and off.  When off, they conduct no current at all.  However when they DO turn on they are not perfect, which is what is meant by Maximum Limited Voltage.  Essentially this is Ohms law:

V = A * R

In other words, the voltage that remains at the MOV is proportional to the current it's shunting AND the MOV's resistance.   In a perfect world, R would be 0 and therefore V would be zero.  A perfect switch, and no voltage across it, but since MOVs are not perfect, even when they've fully activated and are conducting they will have some voltage across them.

BTW everybody, current projections put Idalia over my house Wednesday morning.  I'll report back and let you know about any consequences of my preparation if I can!

Isn't it so that depending on their specs, MOV's can "clip" those occasional transient peaks of current to your amps so your speakers can not express those flash cymbal crashes for example. 

That's the reason that I pulled my Richard Gray MOV power conditioner out from my system and placed a Seimens Pro 140 at the circuit breakers. I'm in S Florida so it's a risk but I don't want any MOV's by my equipment. I think the Shunyata designer feels the same. 

I have a tricked out PI Audio UBER Buss power conditioner though. 

Isn’t it so that depending on their specs, MOV’s can "clip" those occasional transient peaks of current to your amps so your speakers can not express those flash cymbal crashes for example.

Not even a little bit true. You are confusing current with voltage.

An MOV activates when the (for instance) voltage between neutral and hot exceeds a limit, like 300V. Each MOV sits across a pair of wires and does nothing most of the time. There’s no current, no noise, nothing. It just sits there until a high voltage happens and then it turns into a closed switch.

A huge amplifier, playing at maximum output might cause the voltage to DROP below 120V. We call this sagging. The MOV would be even less inclined to activate with a big amp like that.

By the way, Richard Gray’s devices famously use a resonant tank to stabilize the AC voltage and eliminate noise and are parallel devices. If you don’t want it in line you can plug it into the other AC socket and it will still work. They do an excellent job of eliminating noise and keeping the voltage stable even when your amp is causing the voltage to sag.

Having said all of that, I encourage you to use Furman with SMP. It uses series mode protection instead of MOVs, though they do have an edge case that uses an MOV.

It may help you to understand that having a high voltage at your speaker requires more CURRENT (amps) from the wall which will probably lower the Volts at the wall socket. If an amp played music loud AND raised the voltage at the wall you’d have an infinite power device and not even Elon Musk can do that.

The plethora of things audiophiles do, like run dedicated lines with extra thick wires, use power regenerators and voltage regulators is all to keep the voltage at the AC outlet from sagging.

Sorry, current. My Gray was an old model from 2008. The Gray had chokes. Chokes compress dynamics I've been told. 

I have a 30A dedicated line connected to my Uber Buss power conditioner with a 30A Neutrik connector.

My UBER Buss does a better job with noise than the Gray. Power Factor Correction of 1 if memory serves me.

Caelin Gabriel of Shunyata advises the whole house surge suppressor at the breaker box, and no suppressor at the equipment rack and Garth Powell of Audioquest feels strongly for the opposite due to potential RF noise.

@vinylshadow

My Gray was an old model from 2008. The Gray had chokes. Chokes compress dynamics I’ve been told.

When used in series, possibly, but that’s now how RG’s chokes worked. They are in parallel.

PS - You should open up your Uber Buss. I’m sure you are going to find a whole bunch of chokes and coils if it does anything at all. 😁

Caelin Gabriel of Shunyata advises the whole house surge suppressor at the breaker box, and no suppressor at the equipment rack and Garth Powell of Audioquest feels strongly for the opposite due to potential RF noise.

Facts, the National Electric Code requires whole house surge protectors since 2020 AND recommends point of use surge protection devices for sensitive equipment.

The first post explains why they recommend both.

While the NEC requires whole house surge protection, it does not force you to use a surge protector for your stereo or TV. That part is up to you, but I’ve explained why the two are complementary as opposed to exclusive.

Also, anyone who says that a whole house protector could cause RF noise is full of it.

No I won't find any chokes. The designer ran through everything with me. Please don't comment on something you know nothing about. 😁

Caelin Gabriel of Shunyata advises the whole house surge suppressor at the breaker box, and no suppressor at the equipment rack and Garth Powell of Audioquest feels strongly for the opposite due to potential RF noise.

That should tell you all you need to know about these two. They don’t know what they are talking about and are giving bad if not financially dangerous advice.

I would say the same thing about the person who wrote this. They either don't know what they are doing or are lying.  I get the impression the UberBUSS is like the BlueCircle and TLP products. Stack as much capacitance across the line as possible, safety be damned!

"UberBUSS is a power filtration unit quite unlike others on the market. It is filtration only. There are no MOVs or other suppression devices to color the neutrality and introduce noise into the circuitry.