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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Don’t let your “Shark-Bites” come back to bite you!

There has been some discussion about whether push-to-connect type plumbing fittings (Shark-Bites are a common brand name) maintain electrical continuity when using them on metal piping.

As near as I can tell, the unsatisfactory answer is that they are not tested or listed for continuity through them. One thing is certain, any bonding achieved through the connectors is purely “coincidental” as there is certainly no “positive” connection between the brass fitting and the metal pipe.

Coincidental contact between the fitting and the pipe happens when the pipe makes accidental contact with the fitting (intentional contact for this purpose was not designed into the fitting). Whether the pipe is inserted all the way or not, there may be no continuity through the fitting—functional or otherwise.


So what is the definition of electrical continuity–or better yet “functional continuity?” By lining up 3 pennies in a row touching each other, you will have continuity across the pennies, but how would that continuity function under a live load? Would it create an effective ground fault path to trip a breaker if necessary?

Not likely, and likely a bonding jumper would be necessary around such plumbing fittings.

In fact there is actual documentation from the manufacturer of Shark-Bite, push-to-connect fittings that recommends jumping around the fittings when used with metal piping.

I set up a little experiment with an assembly of 4 push-to-connect fittings to see how much voltage drop there would be. The voltage drop of the circuit through the soldered pipe assembly on the left (without any push-in-connectors) was 4.6%.


The voltage drop through the push-in-connector assembly without any load was up-and-down but generally around 25%. By merely wiggling the assembly a bit the voltage drop varied up and down. Under the load of a 1500 watt space heater, the fluctuation varied widely from 45% to 75%.

It was interesting to note that when I initially started the test, the assembly was plugged into an AFCI protected circuit. As soon as I turned on the 1500 watt space heater, the AFCI breaker tripped. I could actually hear the arcing at the connections. Seems like the AFCI functioned as intended.

The experiment and test results pictured above were completed on a circuit that was not AFCI protected.  I found the results to be pretty dramatic.

This is a side view of the assembly, painted black for thermal uniformity.


Here is the thermal image of the assembly prior to turning on the heater.


Here is an image of the temperature within the assembly after 60 seconds.


Here is the temperatures within the assembly after 2 minutes: >356 degrees F.  My decision that it probably was not a good idea to continue the experiment game next, as it appeared I now had two heaters in the room instead of one.

So while this little experiment may lack in some controls that would be present if the same testing was done in a professional laboratory, or by Myth Busters, it is likely good enough to conclude that push-in-connectors cannot be relied upon as a ground fault path and could even be a fire hazard if the piping they were in were to become energized.

The bottom line is that proper bonding is necessary around push-in-connectors installed in metal piping systems—or better yet, perhaps other types of fittings should be used.


By Charles Buell, Real Estate Inspections in Seattle

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