AC Service Ground and Bonding Connections Part II

electricalLightning is responsible for more than $5 billion in total insurance industry losses annually, according to Hartford Insurance Company.

  Here in the Southwest the weather is struggling between winter and spring which brings heavy rains and torrential thunderstorms. These conditions increase the opportunity for electrical surges and spikes. The impact of these storms can cause both personal and property damage. Proper grounding and surge protection can  be your best defense.

Unplugging electronic devices was the old school method of protecting our electronics, however with more microprocessor based equipment that may be built-in or hardwired it becomes difficult to do that.  This can be good and bad. On the good side, this “smart” technology can allow our washing machines to weigh the clothes to determine how much water to use, to our sprinkler systems determining how moist the soil is before it waters our landscape. On the bad side, all of these electronic devices are highly susceptible to the negative effect of power surges and spikes. Any technology less than 10 years old can easily be a candidate for failure due to technological advances based on micro-processor based technology. With all that said, it becomes very important to protect all of these devices from electrical surges and spikes. Even if you live in an area with very little lightening, or thunderstorms, your equipment is still subject to utility and equipment based electrical surges. 

Even though most of us recognize electrical surges as they occur from outside sources, (severe storms, etc.) power fluctuations (or spikes)  from utility switching equipment and even equipment within our house have the ability to create power transients that can have an impact.  So, to properly protect you and your house, you may consider going beyond the typical power strip or point of use (POU) surge protector by having multiple layers of protection.  Obviously, equipment such as a Flat Panel TV, computer or audio equipment require point of use (POU) surge protectors but including  Surge Protection at the point of entry (electrical service panel) will also provide protection for items such as dishwashers, HVAC systems, microwave ovens, washers, dryers and so on.    

tt43kicamiqr72cajlxf3qcaqg2uy9cataa1tgcaozp5xycal1ce1jcanvsd5ycaf7gwszca1aq9vncaubtid9cayql0nrcav7a5t3ca26lasucaabxmn3ca179qr3cagr0p6uca5rqldfca8ochrrProper surge protection cannot be discussed without stressing the importance of  a grounding network for your house. My article on bonding & grounding covers how to identify and inspect your system, but the subject warrants a bit more discussion. The reality of the situation is that your household experiences electrical spikes and surges regularly even without a storm in sight and the source can be any incoming services (Commercial AC, CATV, Satellite TV and Telephone Service) as well as electrical appliances in your house. 

Both the National Electric Code (NEC) and National Institute of Standards recognize the importance of proper grounding  by providing recommendations and standards to increase this level of protection. Read the following articles before you go too much further. For your house to be properly protected, the integrity of the complete house is essential. Bonding and Grounding, Electrical Switches and Outlets (especially testing of the outlets). TIP:  Any outlet without proper grounding should not be used for any electrical equipment that requires protection even when you have a POU surge protector plugged in.

Ensure your grounding systems is up to par:

  1. Test all your outlets as mentioned above.
  2. If your house is over 30 years old and the electrical service has never been upgraded, the water pipe may be the only source of ground. Adding a ground rod would be a good idea at this point. Add the ground rod near the electrical service meter and a new wire between the rod and the ground termination bar in the service panel. It’s okay to leave the cold water pipe connection in tack. The grounding schematic  found below is considered a perfect world design. Creating this form of grounding arrangement will optimize your ground system.
  3. Grounding SchematicIf you have a ground rod and it is over 20 years old, it may be time add a new one. Underwriters Laboratory (UL) recognizes standard copper clad ground rod have a life expectancy of 20 years. If the electrical system has not been upgraded, replacing the ground rod will be cheap insurance.  Its perfectly okay to have multiple ground rods connected together in an array. 
  4. National Standards recognize ground systems with less than 5 ohms of resistance as being acceptable. Unless you live in a very dry climate or have known issues, testing an installed ground rod may not be necessary. If you are thinking you need to replace it,  it’s cheaper to just add it than have it tested.OYL94SCAGD0QOUCAYL04A3CAWYLBW6CAAH81G0CA0L2SH0CAHPGADSCAA7UEPWCAR3W6D8CAEFUGXNCAWGM712CAE6Z75SCAHKAUTPCAM64A17CAYGWHLQCAY41LE9CAXSYBESCAAW9HKRCASITYXC
  5. Ensure that all CATV, Telephone, Satellite services are collectively grounded at the same location as the AC service. TIP:  The closer these services are to each other and the shorter the ground wires used to connect them; the better.  Using the proper grounding hardware, the ground wires can be connected together at the ground rod, or you can use a collection device like the one pictured.    
  6. NEVER EVER connect a ground wire or ground rod to a natural gas pipe.
  7. As noted in the Grounding Bonding Post, having all the incoming services enter the building in the same general vicinity is most desirable.  TIP: With existing houses, these services may already be installed. If you are remodeling or building, keep this item in mind as you go through the process.   When the services all enter from different locations, surges may travel through the house to reach the intended ground source. Unfortunately in those type cases, this can increase the opportunity for the surge to follow an unintended path that may include passing through a television or computer.
  8. Following these items will reduce the risk and opportunity for surges and spikes, however damage from direct strikes are nearly unavoidable. 

 Odds Stacked Against You:  Having  a good ground system as mentioned above will protect you in most cases, however there are certain issues that will work against you. Some of the conditions you can change,  some not. Either way you need to be aware of them. 

  1. Tall structure; having the tallest structure in the general vicinity
  2. Having the largest or tallest trees in the area
  3. Large antennas, such as amateur radio
  4. Located near open water
  5. Older vintage building wiring systems that did not include proper or adequate grounding
  6. Living in an area served by aerial electrical, telephone or CATV lines
  7. Living in an older neighborhood with numerous tree’s in the utility easements
  8. A combination of any of the previously mentioned situations

I know this is a lot of information, but these grounding issues are regularly overlooked until a failure or problem has occurred. If you see the value of this, but its over your head, consult with an electrician about evaluating your system and performing the upgrades for you. My next article will cover the actual surge suppression devices (aka. TVSS). We will see the different classes of TVSS’s, where and how to apply them  and how to recognize a good one.  Look for my next post on Residential AC Surge Protection Using SPD’s and TVSS’s.

Advertisements

2 Responses to AC Service Ground and Bonding Connections Part II

  1. […] from entering the house in the first place. This is why the external ground system mentioned in Part II is so important. Spikes and surges look for the quickest and shortest path to ground.  Industry […]

  2. […] key contributor to both the problem and the solution. Complete the 8 point check list found in the AC Service Bond and Ground Part II.  If your house is less than 10 years old, it would be a fair assumption that all the incoming […]

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: