vinyl_rules OP
02-23-2021
5:00pm
To the best of my recollection the power line to my home was still attached to wiring at the top of the utility pole. The transformer was laying on the concrete deck of my swimming pool with no lines attached to it.
And yes, I was VERY lucky that day. 😱 One other thing that may have been at play that day was the integrity, conductivity, of the electrical service of your home’s System Ground / Grounding Electrode System. The Grounding Electrode System is the grounding used to connect the electrical service entrance neutral conductor and service equipment ground to mother earth. The lower the impedance connection to earth the better the conductivity for diverting lightning and or a high voltage transmission line fault to mother earth. IEEE recommends 5 ohms or less grounding electrode to soil resistance. Here is some reading material. https://www.ecmag.com/section/codes-standards/grounding-electrode-conductors-building http://www.inspectionbureau.com/studyGuides/GroundingElectrodeSystems17.pdf . |
Jea48 said:
”Just curious was the overhead power line from the transformer to the house broken, knocked to the ground, at the pole by the lightning strike physical damage to the pole and transformer? If yes that might explain why your house was spared.”
To the best of my recollection the power line to my home was still attached to wiring at the top of the utility pole. The transformer was laying on the concrete deck of my swimming pool with no lines attached to it.
And yes, I was VERY lucky that day. 😱 |
It is really hard to say how much a surge protector system will protect your home. They help immensely, to be sure, but keep in mind the average lightening bolt has the equivalent energy to lift the RMS Titanic six miles off the ocean floor and set it on a barge 5 feet above the surface of the water. The displacement of the RMS Titanic is 52,310 tons. Yeah, there is some serious energy there. You might be okay, you might not, but you are definitely better with a big professional system than without it, even if everything is fried. I worked for a guy who had a lightening bolt hit his chimney. It cracked the bricks and the resulting EMP pulse took out everything, regardless if it was on or not. |
OP said: A few years back I lived in Arlington, TX. We had a bad thunderstorm roll through one afternoon and lightning struck the transformer that fed our home and several others, and it blew the transformer off the pole into my backyard. I incurred ZERO damage, and my power feed was the closest to the transformer. You were just lucky that day. The SPD (Surge Protection Device) did not save your home that day, jmho. Just curious was the overhead power line from the transformer to the house broken, knocked to the ground, at the pole by the lightning strike physical damage to the pole and transformer? If yes that might explain why your house was spared. Here is some SPD reading material. https://www.nemasurge.org/faqs/ What are surges, transients, and temporary over-voltages, and what are their typical characteristics?Although often used as separate terms in the surge industry, Transients and Surges are the same phenomenon. Transients and Surges can be current, voltage, or both and can have peak values in excess of 10kA or 10kV. They are typically of very short duration (usually >10 µs & <1 ms), with a waveform that has a very rapid rise to the peak and then falls off at a much slower rate. Transients and Surges can be caused by external sources such as lightning or a short circuit, or from internal sources such as Contactor switching, Variable Speed Drives, Capacitor switching, etc. Temporary over voltages (TOVs) are oscillatory
phase-to-ground or phase-to-phase overvoltages that can last as little as a few seconds or as long as several minutes. Sources of TOV’s include fault reclosing, load switching, ground impedance shifts, single-phase faults and ferroresonance effects to name a few. Due to their potentially high voltage and long duration, TOV’s can be very detrimental to MOV-based SPD’s. An extended TOV can cause permanent damage to an SPD and render the unit inoperable. Note that while ANSI/UL 1449 ensures that the SPD will not create a safety hazard under these conditions; SPDs are typically not designed to protect downstream equipment from a TOV event. TOP What are multi-mode SPDs – why do I need L-L (line-to-line) and N-G (neutral-to-ground) protection?Multi-mode surge protective devices (SPDs) are devices which comprise a number of SPD components within the one package. These “modes” of protection can be connected L-N, L-L, L-G and N-G across the three phases. Having protection in each mode provides the protection for the loads particularly against the internally generated transients where ground may not be the preferred return path. In some applications such as applying an SPD at a service entrance where both the neutral and ground points are bonded there is no benefit of seperarate L-N and L-G modes, however as you go further into the distribution and there is separation from that common N-G bond, the SPD N-G mode of protection will be beneficial. Here is a video showing what happened when a power transformer failed. https://www.wwltv.com/article/news/local/jefferson/transformer-blows-in-kenner-killing-power-for-mor...
An SPD would be worthless in this instance if the high voltage power came in on the electrical service wiring of a home. |
I’m not sure about the value off a separate panel off the main supply as
you still only have the single electrical line feeding your home. Benefits: - Ease of running additional circuits
- Reduction in voltage drop thanks to the massive cable you will run to your sub panel. If memory serves, you get better voltage this way than running individual lines all the way back. It's been a while since I did the math though, others with more recent electrical experience should double check me.
- The possibility of running 220V conditioners/transformers at the sub panel.
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I’m not sure about the value off a separate panel off the main supply as you still only have the single electrical line feeding your home. I’m not an engineer but I think having separate circuit breakers for each line dedicated to your system would suffice. I had NEMA 5-20 outlets installed because I was installing 20 amp lines. If I had it to do over again i would have installed four 30 amp lines terminated into NEMA 5-30 outlets and one 50 amp line terminated into a NEMA 5-50 outlet. Yes, I know this is overkill but I have the space for this in my breaker panel. Many of the after market filter devices that purport to clean up your AC actually choke your AC and I don’t think ANY are rated for more than 20 amps. IMO more current availability through a 30 or 50 amp circuit is more important than any aftermarket filtering. And there are a very few power amps that require more than 20 amps for full power output and you need either a 30 amp circuit or two separately wired 20 amp circuits for them. HOWEVER, you may likely void your equipment warranty if it’s fed more than 20 amps. As always, YMMV 😎 NEMA Info at https://www.stayonline.com/product-resources/nema-straight-blade-reference-chart.asp |
Hope the OP doesn’t mind if I pop in with a few questions...building a dedicated room, so I have saved the idea of dedicated lines (2 or 3). I get the recommendation for separate circuit breaker for the lines dedicated to the system from other supply to the room. Presume separating audio and video components would be ideal. What about a separate panel off the main supply? Is this overkill? Any suggestions on electrical upgrades such as medical spec. outlets?
The whole home surge protection is a definite add-on, if not mandated by code. |
Thankfully I had a Panamax on my system years ago and good surges on all major appliances, as a strong surge hit locally. Fried the Panamax and a couple of other surges but saved my equipment and appliances. Neighbors werent so lucky.
I've got to get that whole house version installed . I've been putting it off. |
Juice in ground around here. Where it should be.
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Just make sure that if you get a lot of lightning in your area that you
periodically check the whole house surge protector to see if it is still
functioning. Good point. Of the 3 I mentioned only the Siemens has an audible alert. |
Just make sure that if you get a lot of lightning in your area that you periodically check the whole house surge protector to see if it is still functioning. I've had to have them replaced twice due to lightning hitting close enough and the surge taking them out. That's also a reason to still supplement with protectors at the outlets
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When you consider the cost and the protection it provides I am surprised it isn’t included in the electrical code. Square D, Siemens and GE offer protectors that replace 2 breaker slots from around $80 to $150. They are super easy to install. Turn off the power, push in and attach the pig tail to an existing neutral bus bar and you are good to go. Just make sure it’s the right type for your panel. Square D, for instance, makes narrow and normal width breaker panels. They are not always easy to find via searching. Siemens also makes units which are pricier and harder to maintain, that require a separate 2 pole breaker. Honestly don’t know why. Search for BoltShield if you have a Siemens panel. Based on literature I’ve seen it seems that as of 2020 surge protectors are actually required in new panels or significant rework. As you pointed out, they are cheap and well worth it. I first installed one around 2000 but it was not a requirement. I've never heard of lightning actually destroying in wall wiring, but that would explain why the NEC would want to include it. It's heavily biased towards life safety and less towards appliance safety. In-wall fires are definitely something the NEC would try to avoid. |
OP, that's the best thread headline ever. |
When lightening hit my house I lost $16,000 worth of stuff but not the whole house surge protector. It sailed right through it. It was not defective. |
The Environmental Potentials EP-2050 does more than a standard whole house surge protector. In addition to surge protection it provides waveform correction and conditioning. My unit has been operating perfectly for over fifteen years.
I brought it to Costa Rica for five years where the power is terrible. My neighbors were regularly loosing TVs and such. We never had a problem. |
When we were building our house 4 years ago one of my buddies who had a similar experience to your neighbors told me to have a whole house surge protector installed which I did. When you consider the cost and the protection it provides I am surprised it isn’t included in the electrical code. |
Sound advice vinyl _rules! |
