Our House: Electrical Grounding - 2013 & 2019
Photos Copyright© Robert L. Vaessen
On the 4th of June, 2013 - A large thunderstorm cell moved through our community.
During that storm, a resident's home was damaged when lightning struck their home. Initially, the news (television reports) and some reports came into our community manager that indicated a lack of proper grounding. Like many of you, I was concerned. I didn't want a hole blown in my ceiling, and I didn't know what to look for when checking for grounding.
I did some research on the internet (it's always better to have some knowledge before the 'experts' show up), then I called an electrician. The electrician came out to our house and inspected the grounding. My wife was at home when the electrician came over, and I got home from work just as he was 'Explaining' to my wife that we needed an in-ground grounding rod in order to protect our home…
After some initial questions, I started asking him about the NEC (National Electric Code) requirements for residential properties (I had done my research). According to the NEC code, residential properties (in Aurora/Colorado) must employ at least two grounding methods to protect the home and it's occupants. Two of the three primary methods are employed in my home. Grounding to metal water pipes (My home has copper pipes for water), and grounding to concrete encased electrode (Ufer grounding - Named after Herbert G. Ufer).
This electrician was trying to tell me/my wife that we needed a third method. He was telling my wife that we didn't have a grounding rod (which was true). He was trying to sell us an additional grounding method. Soon after I started asking questions, he changed his tune from 'You need this' to 'Its recommended'. I specifically asked him what NEC said in regards to how many grounding methods are required. What I had read indicated that two methods are required, and two of those methods must come from a list of three primary grounding methods (the third method on the list of three was the grounding rod method). Additional methods are permitted, but I couldn't find anything in the NEC code (online I found references as late as 2011) that indicated a requirement for a third method.
I asked the electrician whether the copper wire outside my house had been stolen. I asked him whether I already had a grounding rod. I didn't have a grounding rod, and it didn't appear that anyone had stolen any copper wire off the back of my house. I asked whether he tested the grounding in my home. I asked him if my house met code - He answered yes to both questions.
A lightning strike directly to your home can cause a lot of damage whether or not you have proper grounding protection (to code). If you suspect that your grounding components have been stolen, it's a good idea to have your home's grounding and electrical components inspected. In the event of a direct strike (Lighting strikes your home), a whole house surge protector may not be able to prevent damage to your home's electrical system (and your electronic devices). However, a surge protector may help prevent damage if lightning strikes near your home (Surge protectors cover varying levels of protection). The surge might travel through your home's electrical system, and a whole home surge protector might offer some protection. FYI: According to articles in 'Windpower Engineering & Development' a lightning bolt carries anywhere from 5kA to 200kA, with voltage varying from 40kV to 120kV.
In the final assessment (for my home); no one had stolen any of my grounding components. My home was properly grounded, and I didn't need any additional grounding. That's when I asked the electrician if he could install a 'Whole Home' surge protector. I'd read about these devices, and I already knew how much they cost. He indicated that he could. As a matter of fact, he had all the necessary equipment with him. I asked what brand of surge protector he had. He named a brand I'd already read about, and I asked him to go ahead and install the 'Whole House' protection. Now if lightning strikes, I've got one more layer of protection to keep lightning from frying all the computer and electronic goodies scattered all around the house (many are protected by power-strip surge protectors).
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Author: Robert L. Vaessen e-mail: