Tin-foil Hats and Your Home’s Electrical Grounding System

Like most of my readers, I have been known to occasionally don a tin-foil hat when necessary.  I have avoided stepping on cracks and certainly tilted at windmills when necessary.

Science usually makes us give up our wishful thinking (the desire for the simplicity of tin foil) and helps us pick and choose actually conquerable windmills–or at least understand the consequences.

There will always be causes worth doing battle with as long as there are idiots to create those causes.

Often it is seemingly impossible to tell the difference. And, isn’t that what keeps us all entertained all the days of our lives?

But back to aluminum foil hats, and protecting ourselves from the unknown or seeking information from the ether. Once upon a time in a crawl space (where I have most of my epiphanies and meaningful conversations with the unknowable and the unseen), I came across an instance of where someone was clearly attempting to communicate with the void—or perhaps merely attempting to “avoid” something.

Metal piping in one’s home must be bonded and/or grounded to the house electrical grounding system. We can clearly see in the following picture that it was once connected, but now it looks more like something you might use in a search for E.T.

In this particular case this “avoidance” resulted in the house not being grounded at all at the home itself, because there were no ground rods or other means of grounding the electrical system. When this occurs grounding is achieved by the wire that runs back to the utility company transformer at the street. This condition makes it very difficult to keep static charges from building up on the house’s electrical system. 

If the ground wire at the utility pole is lost it can become even more difficult and can result in considerable damage to electronic equipment in the home.

It is now time to communicate with the electrician about repairs–they rarely tilt at windmills and I have never seen one wear a tin-foil hat!

By Charles Buell, Real Estate Inspections in Seattle

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What is that dang bare copper or aluminum or green ground-wire for anyway?

The grounding/bonding wire.

This poor wire is a bit schizophrenic.  It has different names depending on where it is terminated and many people accuse it of doing things it is not responsible for. 

dscf7009For example when we run this wire to our house grounding electrode system (ground rods, Ufer grounds, metal water pipe etc) we call it a GEC, or Grounding Electrode Conductor.  When we run it from switches, receptacles, lights and other points of use to our electrical panels we call it an EGC, or Equipment Grounding Conductor.  The two uses are tied together as if they were “one” in your electrical service equipment (your main panel). 

This leads to considerable confusion over what it actually “does.”

In simplistic terms, the GEC (grounding electrode conductor) is a path to dissipate static charges and surges safely back to the earth via the ground rods, Ufer ground, or metal water pipe it is attached to.

The EGC (equipment grounding conductor) serves two functions:

  1. It provides an effective ground fault current path to trip a breaker or blow a fuse in the event that there is a short to the metal components being bonded.
  2. It provides a path to earth to dissipate static charges and surges that would otherwise build up on the electrical system.

There is a myth that is pervasive among home inspectors, and even some electricians, that the equipment grounding conductor is there to prevent shock.  There is another even more serious myth that all electricity is trying to go back to earth and this is how it gets there.  It is really best to forget both of these myths if one is to stay safe.

The reason for the confusion is that if there is a “short” to the grounded metal components and the circuit is tripped off, one obviously can’t get a shock from something that is turned off.  The dangerous aspect of this is that the metal components can be energized up to the amperage of the circuit (and even beyond) without tripping the breaker and a person touching the metal components would still get a shock.

If the person happened to be touching the grounded metal component at the very time the fault occurred, they could still get a shock–albeit a very short one.  It still could be enough to arrest one’s heart or scare one off a ladder resulting in possible serious injury.  So in this respect the equipment grounding conductor is not a true shock protection component of the system.

Obviously with no ground wire at all we have no chance of shutting of the equipment in the event of a short and we do actually increase the chance of getting shocked.  The solution is not just to install the ground wire–because that will only improve the situation–not eliminate the risk.

To reduce the risk of shock we must install GFCI protective devices, either as receptacles at points of use or as circuit breakers that protect the whole circuit.  We do not even need a ground wire to gain this protection.  The GFCI devices do not need a ground to function and this is why they are so important and valuable on older homes without equipment grounds until the systems can be upgraded.

The most critical thing to remember when you are working around live wires is as long as you do not contact grounded metal components and are physically isolated from the actual earth (not standing barefoot on concrete or kneeling on the wet ground) you have pretty much zero chance of getting a shock when you touch an energized component.  Of course if you touch the neutral and hot wires you will indeed get a shock.  Because we might make a mistake or not realize when we are grounding ourselves, we install GFCI devices to take care of us.

It is best practice to never assume metal components are not energized.

By Charles Buell, Real Estate Inspections in Seattle

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Grounding and Bonding—are you a victim of urban legend?

If you think electricity is always trying to “go to ground”—you may be a victim of urban legend.

transformer3For a home inspector this has to be one of the ultimate “urban legends.”  It is a widely held belief (that is further promulgated by inspection training schools).  It is “common knowledge” that electricity is “always seeking the ground.”

We cannot truly come to grips with the importance of a home’s electrical grounding system, and the bonding of the home’s metal systems (water pipes, drain pipes, gas pipes etc), until we get this myth corrected in our minds.

If I have any readers left at this point, I consider it a great honor.  I am well aware that the vast majority of my readers do not give one hoot about any of this as long as everything works when they plug things in or turns on when they flip a switch.

All readers, in my opinion should give a hoot however, in order to not get shocked or electrocuted while using those beloved appliances. I think that electrical system grounding and bonding should be taught in schools—it is just that important and only becoming more so every day.

Contrary to urban legend, the way the electrical system actually works is that electricity is attempting to return to its “source.”  If this was not the case, we all would find it very inconvenient if every time we wanted our flashlight to work we had to stick a wire in the ground.  Head lamps would be even more interesting.

In the case of your home’s electrical system, “the source” means the transformer out at the street.  Many people, including home inspectors assume that everything is returning to “ground” because we ground the electrical panel with all these big ground wires that run to rod rods, concrete encased electrodes and/or buried water pipes running to the home.

It is understandably confusing—especially given that electricity always knows what it is doing and we do not. 

During normal operation of the electrical system, when you turn on your toaster, current flows through the toaster elements to adequately burn your toast the desired amount, and then returns to the transformer via the neutral conductor.  The fact that there are ground rods connected to this neutral conductor in the service panel is of no consequence because the path over the neutral wire is so much better (easier) it simply does not take the path via the ground rods (or at least not enough to notice).  When it does take that path, it means there is a HUGE problem with the electrical system.  The earth does not make a very good way to conduct the current back to the transformer—and besides that, it drives the earthworms crazy.  But that is in fact what happens.  The electricity would run through the earth, up the utility company ground rod/wire at the pole and back to the transformer.  So in this sense, the electricity is not completing its circuit to the ground–it is completing it back to the transformer—back to its source.

When understood in this context, I hope it helps make it a little easier to understand why all metal components in the home have to be properly connected to the grounding system so that if the metal parts were to become energized, you would not be the only or easiest path between the energized pipe looking for a way back to the transformer. This becomes more of a matter of “how much” shock you will get as opposed to eliminating the chance of getting shocked altogether (and why GFCI’s are so important).

In most homes this becomes fairly straightforward, but because so many people have no clue about how all this works, the grounding/bonding systems often become compromised.  Take a look at the following picture. 

Water pipe bonding/grounding compromised by plastic components

Water pipe bonding/grounding compromised by plastic components

For some reason someone installed additional “plastic” shut-offs on the two water pipes.  They are near the main water shut-off where the water pipe runs through the foundation to the street.  This home was built at a time when the only means of grounding the electrical system was the water pipe to the street.  There were no ground rods that would have provided some redundancy.  The installation of the plastic components leaves the house grounding system to rely on the utility company ground rod at the transformer. If that grounding is severed (WAY more common than one might think), it places the entire electrical system at greater risk in the event that lighting should strike the transformer and there is no place for other types of high voltage surges to be directed to the earth.  The purpose of the ground rods (water service pipe, concrete encased electrodes etc) is to dissipate high voltage surges that can be imposed on the system from either the utility, nearby lightning strikes or even created within the home (it does other things too but I want to keep in simple right now).  These types of surges are why surge protectors are becoming more and more important in the home although the only solution to a direct lightning strike is to replace the damaged components. 

Another essential purpose of all those ground wires running all over the home and attached to all the metallic systems in the home is to create “an effective” path back to the service panel so that the circuit breakers would trip off in the event of an electrical fault to those metal components. Sometimes clearing a fault that will trip the breaker would indeed still give you quite a shock–resulting in even death–but the house won’t burn down and cremate you.  GFCI’s, Ground Fault Circuit Interrupters, can and will keep you alive however.  Nobody wants to go to their own cremation prematurely.

So to recap, our house grounding system has nothing to do with returning current to earth–it is always going back to the transformer–back to its source.

I highly recommend that anyone that has serious reservations about the information above (or wants a far more in depth treatise on the subject), please check out the Mike Holt video on grounding and bonding.

Charles Buell, Real Estate Inspections in Seattle


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