Why whole house surge protectors are not enough

@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?