Whole house surge suppressors

Re: Whole house surge suppressors

Peter_V wrote: »

When the array was installed the electrician wired in a lightning suppressor at the PV cutoff switch (the round can sticking out the bottom).

However, I don't think this will protect the rest of my house so I was thinking of installing a Leviton 51110-1 SPD:

Your answers starts with some basic concepts. And numbers. First, no protector is protection. You are not the only one here who completely missed the point. Destructive surges seek earth ground. Either that energy dissipated harmlessly outside the building. Or it is inside hunting for earth destructively via appliances. You select Option A or Option B.

Option B is what most everyone has. A direct lighting strike to wires down the street would be a direct strike to household appliances. Surge damage means direct strikes with the same current both incoming on one wire. And outgoing on another wire of that appliance. The only protection means that current is earthed before it enters the house.

The most important component of every protection 'system'. And nobody even mentioned it? Single point earth ground.

Either a 'whole house' protector connected every single wire in every cable to earth (or that wire connects directly to earth - ie cable TV). Or all protection is compromised. Protection means every wire connects short (ie 'less than 10 feet') to earth. Or the protection system is ineffective.

AC is three wires. All three must be earthed. Two via a 'whole house' protector. Telephone is two wires. Both must connect to earth before entering. Every telephone subscriber interface already has that 'whole house' protector.

You had satellite dish damage because the earthing somewhere was defective. That satellite dish must enter at the service entrance (with telephone and AC electric) to make a direct (ie 'less than 10 foot') connection to the same earth ground electrode. And the dish itself must be earthed. Either a direct lighting current goes to earth via the dish (not via LNB). Or you have damage.

Protection is always about an electric current path to earth. A 'whole house' protector means protection for everything inside. Protection means no energy anywhere inside a building. A plug-in protector sometimes makes surge damage easier.

The nearby strike? Well, a long (100+ feet) wire antenna was tens of feet from a lightning strikes. So thousands of volts appeared on its incoming lead. We put an NE-2 neon glow lamp (same is inside nite glowing wall switches) from that antenna lead to earth. Then the thousands of volts was only tens of volts. The energy content of nearby strikes is almost zero. So milliamps through an NE-2 result in a massive voltage reduction. Worry not about nearby strikes. Worry about the actual current (typ 20,000 amps) from a direct lighting strike. A strike to AC wires (overhead or underground) down the street is a direct lightning strike to every household appliance.

Re: Whole house surge suppressors

westom, I'm the one that had satellite dish damage but I'm not the OP.

Re: Whole house surge suppressors

westom wrote: »

The most important component of every protection 'system'. And nobody even mentioned it? Single point earth ground.
.

Why "single point"?
How and why is a "single point" earth ground better or more effective than multiple grounds rods?

Re: Whole house surge suppressors

JESSICA wrote: »

Why "single point"?
How and why is a "single point" earth ground better or more effective than multiple grounds rods?

Lightning struck a tree some 30 feet from a horse. So the horse died from a direct lightning strike. Ok. It is electricity. So you know this. There was an incoming electrical path. And an outgoing electrical path. A critical fact that everyone knows from school science.

Lightning is a connection from a cloud to earthborne charges maybe five miles away. What is a shortest connection? Three miles down to a tree. And four miles in earth to those charges. A shortest path was also up the horse's hind legs and down its fore legs. Horse was also in a shortest path from cloud to charges. Horse died because it did not have a single point ground.

Humans do same. During a lightning storm, keep feet together. Single point ground. Lightning is incoming via legs. But has no outgoing path; no outgoing current. No death.

Same applies to protecting appliances in a house. BTW, did some scummy salesman have you thinking protection is a magic box next to an appliance? Protection is about viewing the entire house and nearby items - ie overhead utility wires, cloud, etc.

Single point ground is why static discharge to an Ipod does not destroy it. Why barns have a buried copper wire loop so that cows are not killed. Why golfers stand with feet together during a storm. And why a home without single point earth ground earths surges via household appliances.

If any wire enters a structure without first connecting to that earth ground, then that structure has no effective protection. Even applies to a satellite dish.

This is science from over 100 years ago. And is completely unknown to so many educated only by advertising and hearsay.

Re: Whole house surge suppressors

mike90045 wrote: »

How do you manage several wide spread structures fed from 1 meter?

A professional application note demonstrates single point earthing. Two structures. Each must have a single point ground. Any wire entering but structures must connect to that structures single point ground before entering:
http://www.erico.com/public/library/fep/technotes/tncr002.pdf

Earthing requirement applies to every wire in every cable. Even if that cable is underground.

If two structures violate the concept, then a direct lightning strike to one building may become a lightning rod connecting that surge into appliances inside the second building.

Earthing wires to some 3 meter ground rods means a massived increase in surge protection. But better informed builders start protection when footings are poured. Ufer grounds were pioneered in munitions dumps so that direct lightning does not cause explosions. Technology is that routine when surge damage is not acceptable. Effective because concrete is a good electrical conductor.

Buried ground loop is another solution. Or how one solve earthing atop a rocky mountain:
http://scott-inc.com/html/ufer.htm

A case study of how all surge damage was eliminated in a Nebraska radio station by not wasting money on protectors. By fixing defects - bad earthing. They even fixed the utility pole transformer earth ground. Each layer of protection is only defined by that earthing electrode - each single point ground; not by any protector:
http://www.copper.org/applications/electrical/pq/casestudy/nebraska.html

Welcome to what advertising and salemen in a big box TV / computer store will not discuss to enrich themselves at your expense.

Re: Whole house surge suppressors

As I mentioned, there are many types of grounding for many different purposes and bodily hazard grounding is a discipline all of its own, although it is the ugly one most people often experience "first hand" pun intended.

If you really think about it, a "path of least resistance" has very little to worry about. The electrical current will pass through it with very little resistance and very little effect with very little surge or rise. It is the "path of some resistance" that causes problems. It is here that arcing, burning, and "shocking" occur. A "shock" is merely a rapid rise or surge current. There is electricity coursing through your body at all times. It is harmless. It is what makes your heart, brain and nervous system function. Death does not occur from electricity merely passing through your body. It comes from a surge or rapid rise or over-current. If your body presents too much resistance in the path there will be a rapid rise or "shock" which occurs or even burning.

Remember the electric fence trick. Five kids hold hands in a line, the one at one end grabs an electric fence. The one who grabs the fence does not feel a shock, nor do those in the middle, it's the poor little kid on the other end that doesn't know what's being planned for him that gets whacked.

A mild electric surge in the body can cause the heart, brain, or nervous system to malfunction or death to occur, a large surge or arc can cause burning or even vaporize the body.

Just like a filament in light bulb. If you stay within the allotted voltage it works fine. If the resistance is too great for the increase in voltage, pow! The filament burns and if the voltage is high enough to arc within the bulb the whole bulb will explode.

More people die from a result of burns when electrocuted than do from current.

ESD grounding is a different discipline and the single point ground iPod illustration does not exactly apply. An electrostatic discharge to a specific portion of an iPod could result in a total loss regardless of whether or not there was a single point ground to the device. Even the arc caused by electrostatic discharge generates an electromagnetic field which of its own could cause damage to components.

All grounding disciplines come back to the same issue. Equalizing potential. If a person is grounded to the same plane as the iPod they touch there will be no discharge. This is the reason electrical component assembly workers wear ESD straps which are grounded to the same plane and the assembly they are working on. In many cases they will actually seek to isolate them from earth grounds or other magnetic fields.

Equalized potential is the reason single point grounding works for protection where multiple grounds do not.

Shortest path to ground as previously mentioned is not a path determination for lightning or arcing. Watch some slow-mo videos of arc flash if you don't believe this.

Re: Whole house surge suppressors

techntrek wrote: »

Several incorrect pieces here.

The question was about single point ground functions and why. Your post makes no sense by completely ignoring Jessica's question, the context, and purposes of earthing.

An electrically shortest path is not "path of least resistance". Read what BB posted. Path of least "impedance" (radio frequencies) is important. Involves other factors including and not limited to a conversion of gas to plasma. Other factors were irrelevant to Jessica's question.

A shortest electrical path is not five miles across sky. Shortest path is down to a tree. Then through earth. That example demonstrates an answer to Jessica's question. And why superior surge protection best begins when footing are poured.

Jessica's question was about single point ground. Where does your post answer questions by Jessica or mike90045? Whether the electrician keeps one hand in his back pocket (a good practice) or not is irrelevant.

Back to what others are discussing.

Equalized potential discussed by thehardway is part of a solution. Single point earth ground must do two things: equipotential and conductivity. Since conductivity cannot be made sufficient, then we also need equipotential. And since equipotential is not sufficient, then we need better conductivity. Both electrical concepts are what make a 'whole house' protector so effective. And why a protector inside a building (too close to appliances) is ineffective.

Protection is always about an electrical current path to earth; not about voltage. That means a lowest impedance (not resistance) path. Impedance is why the connection must be so short (ie 'less than 10 feet') without sharp wire bends, no splices, not inside metallic conduit, and separated from other non-grounding wires. More reasons why plug-in protectors do ineffective protection.

Concepts of conductivity and equipotential are engineering reasons. For a layman, that translates to single point earth ground, a shortest path to earth either directly (from cable TV) or via a protector (AC electric, telephone), every wire in every cable (even if underground) connected to that ground, and where energy dissipates.

Anything that would protect inside a house means energy is inside and hunting destructively for earth via appliances. Means that protector sometimes makes damage easier. Anything inside to make energy magically disappear is a myth. Protection is always about 'diverting' surges on a harmless path to earth.

Peter V asked, "The EMP thread got me thinking again about protecting my systems from nearby lightning strikes." Worry not about EMP. The horse was not killed by EMP. Protection for everything inside a house is the actual current path. The horse did not have single point ground; so was killed. The NIST (US government research agency) says what all effective protectors do:
> You cannot really suppress a surge altogether, nor "arrest" it. What these protective
> devices do is neither suppress nor arrest a surge, but simply divert it to ground, where
> it can do no harm.

"Divert". Protection is always about the current path. Effective protection means current is not inside a house and does not create a high voltage. That current will flow not matter what tries to stop it. Only fools, retail salesmen, and myths stop or block surges. Protection is always about where energy dissipates. Every protector is only as effective as the relevant topic here: single point earth ground.

Re: Whole house surge suppressors

thehardway wrote: »

If you really think about it, a "path of least resistance" has very little to worry about. The electrical current will pass through it with very little resistance and very little effect with very little surge or rise. It is the "path of some resistance" that causes problems. It is here that arcing, burning, and "shocking" occur. A "shock" is merely a rapid rise or surge current. There is electricity coursing through your body at all times. It is harmless. It is what makes your heart, brain and nervous system function. Death does not occur from electricity merely passing through your body. It comes from a surge or rapid rise or over-current. If your body presents too much resistance in the path there will be a rapid rise or "shock" which occurs or even burning.

Remember the electric fence trick. Five kids hold hands in a line, the one at one end grabs an electric fence. The one who grabs the fence does not feel a shock, nor do those in the middle, it's the poor little kid on the other end that doesn't know what's being planned for him that gets whacked.

...

Shortest path to ground as previously mentioned is not a path determination for lightning or arcing. Watch some slow-mo videos of arc flash if you don't believe this.

Actually death occurs with less than a tenth of an amp across the heart, no burns necessary.

Trust me on the fence thing - every single person in that chain feels it.

Glad you mentioned arc flashes, after posting I realized I should have mentioned the lightning bolt itself - perfect example that it follow the path of least resistance and not the shortest distance. If it followed the shortest distance lightning bolts would be perfectly straight from the clouds to the ground (and cloud-to-cloud). People have been know to get zapped by lightning 5 miles away from a storm.

Re: Whole house surge suppressors

everybody should just calm down a bit. this is a very involved subject matter and the op should go with as much as he can and to a single point ground. now understand here that a single point ground does not necessarily mean a single ground rod as long as all rods are bonded together. it just makes it a larger single point ground and is a better ground.

as to somebody or even a horse standing near a lightning strike and falling down dead does not mean the lightning hit them as emp levels near lightning can be lethal in and of itself.

do know that concrete, dirt, and rocks are not good grounds or conductors of electricity for if they were we would not be striving for such a large contact area with them. what often makes them conduct is the water and metal content in them and this is still a high resistance so to overcome it a large contact area is needed. in fact in at least 99% of all cases an 8ft copper ground rod is really insufficient for a good ground point, but we strive for a good reasonable compromise.

also note that satellite dishes have to be grounded too and to that single point ground.

as to mike's example of the multiple buildings, i feel it is a great question. we could even include each and every power pole in this question too. ideally, they should all have a single point ground of very low ohms resistance bonded together, but this becomes nearly impossible to achieve over large distances. if 2 buildings, and even a pole, are somewhat close together i would bond all of the ground rods together underground. this helps to prevent differential voltage potentials from developing between them. with greater distances one might still see voltage potentials develop, but hopefully the resistance in the ground itself will dissipate large potentials.

Re: Whole house surge suppressors

BB. wrote: »

Lighting has significant radio frequency energy content... So you have to look at the "impedance" and not simple resistance. Becomes a much different beast than DC / low frequency resistance calculation.


-Bill

Are you saying lightning is an AC power event?



As a disclaimer first let me say that no one understands the lightning process entirely. That said we do know a few things about it from studies (fulminology) and high speed video capture. We just aren't sure about the whole cause and effect relationship or what comes first as it is too big a picture to study at full scale.

Here is a very impressive and revealing high speed capture of a lightning strike.

http://www.youtube.com/watch?v=-bvmEYxEYiA&feature=related

The first flashes of light you see are the setting up of the "stepped leader".

This sets up an "ionized channel" and as it approaches the ground a "positive streamer" transcends upward and connects to it. This results in a "return stroke" which is the most illuminating and concentrated part of the strike. Once the channel is formed there are usually several pulses which take place in the channel. Notice how long the return stroke seems to remain, this is actually several upward and downward strokes within the channel.

Lightning can be either a negative or positively discharge. Positive discharge lightning is typically the most damaging.

Lightning can emit upwards from a fixed point as well as downward from the atmosphere. Notice the upward movement in the video from several fixed tower locations. Also note how lightning does tend to strike in the same location more than once in this video.

Lightning is neither a true DC circuit nor is it a true AC circuit. It most resembles a DC pulse discharge followed by a return DC pulse discharge. This might be referred to as a single cycle AC event but that is a bit of a stretch. Neither the amplitude of the pulses nor frequency of the pulses are seldom equal.

This may resemble a diminishing wave form but it is not a true AC current caused by pole reversal.

The radio frequency (Xray and gamma ray) associated with lightning it is not likely part of the actual discharge but most likely the result of the excitement of the atmosphere around it either during or prior to it depending on the theory of development you subscribe to.

Bill,

As such I am not sure I understand your reference to impedance as impedance deals with AC circuits exclusively. Are you referring to the inductive and magnetic currents set up in the grid by a electrostatic event or are you referring to man generated current and not lightning? Can you explain?

The one constant in all of this is that nature is always seeking to equalize potential or reach balance. This tendency to equalize potential weather it be radioactivity of isotopes (nuclear), High pressure/low pressure gradients in weather (Wind), ESD (lightning) thermal adsorption and absorption Solar thermal and geothermal), tidal flow, or hydraulic pressure (Hydro), is the basis for renewable energy. Any time you can capture and harness a naturally occurring imbalance you have potential energy. It is useable to perform work until it is back in balance or zero potential.

This is the theory behind single point grounds. Zero potential means zero energy to destroy electronic circuits. Keep it balanced.

Driving multiple grounds that are disconnected and have different potentials create a likelihood that an uncontrolled discharge can and will take place due to imbalance. This goes against nature.

Hope this helps answer the questions. I agree even a small current in the body can kill a person but statistics say it is the heating portion of electrocution that actually causes more fatality.

Good discussion. You won't find this from the salesperson when you go to buy a SPD at your local big box store.

Re: Whole house surge suppressors

westom wrote: »

The LED can only indicate a type of failure that means the protector was ineffective - grossly undersized.

Unless you're talking about a specific product, how can you say what the LED indicates? On mine, the LED indicates full protection is present. The indicator light is extinguished when full protection is no longer present. It does not indicate a "type of failure".

westom wrote: »

Yes, the protector is good for a limited number of transients. So it should still be effective a decade later.

Huh? Whether it should be effective a decade later, or a day later, depends entirely on the number and nature of transients the SPD must deal with.

Re: Whole house surge suppressors

whether a byproduct of a strike or not, the energy is originally from the lightning. this is true of the thunder and all frequencies produced. it is ac energy, or pulsed dc depending on how you look at it, and is quite strong throughout the spectrum and gradually weakens as it goes up in frequency. impedance does apply even to a pulsed dc waveform. the only difference between ac and pulsed dc is the reference point.

peter,
i did go to your subject matter and i encouraged you to go ahead with something. i can't vouch for that particular one, but there are many of them out there. they usually take 1 of 2 forms. 1> mov which many here often see and 2> gas discharge tubes. gas tubes are short lived as it will work fast and at a low voltage, but once fired is kaputt. you may even want to check out midnight solar's future surge protector as seen here just about halfway down,
http://www.midnightsolar.com/

here's the manual on them,
http://www.midnitesolar.com/pdfs/SPD_Installation_manual_3%20_2_.pdf

it has some very large movs in it compared to other protectors and the blue led is kinda neat too. i believe there are 2 leds in the protector, one for each leg of the ac. they are bigger in size than the delta surge protectors so if room is an issue you may want to be sure they'll fit first.

edit to add:
the term protector may be overstating its function, for the record. they can increase the likelyhood of a survival, but are no guarantee. in fact, i doubt any such protector will survive a direct strike to protect anything. something like a faraday cage might do better in such a case, but that's not as easily done and isn't readilly marketable for everybody. as i've said many times, there are no guarantees when it comes to lightning as it does whatever it wants to. we can try to persuade it to go elsewhere though.