Lightning strikes ... interesting letter

[Klondike Mike]

I came across this letter to a recent audio magazine and the reader shared his experience with lightning strikes to his home and how it effected his equipment. The points raised were ones I thought would be of interest to anyone concerned about lightning strikes.

 

[Captain Kilowatt]

I have a couple issues with this starting with the statement that in NJ it is law to have your incoming electrical lines grounded to an 18 inch buried rod. 18 inches is NOTHING and certainly NOT up to the National Electric Code at all. The second issue I have is that lightning does not travel UP the ground wire. In several transmitter installations we had we lost many sets of high voltage rectifiers in the TX power supplies until we installed suppressors on the AC power lines. After that none were lost. It depends on what you install. Those little ones that claim to protect the whole house usually do NOT. Better units costing a few hundred dollars at minimum do work. The MOV devices they use are rated to handle many tens of thousands of amps. This one typw we used. i have one myself and was going to install it this summer but never got around too it. I will get it done this winter.

http://www.nautelnav.com/solutions/ndb/spu2-surge-protection-unit/

 

[Klondike Mike]

I have a couple issues with this ...

Well, almost a hundred people have viewed this thread and only CK had issue with some aspects of it. I am not in total agreeance (yes, some may say this is not a word but I like it) with everything in the letter as well but since I do not have expertise in the lightning/grounding aspect of things, I thought I would post the letter to get other valued opinions.

The issue of lighting traveling through the ground was interesting as the letter stated he had everything disconnected except the ground from the cable.

I was surprised as well about the whole house surge suppressor being installed and effectively useless. I have been looking into these as well from the big box home improvement stores and they go for around a 1-2 hundred dollars here in Canada (ya, I know, Canadian dollars).

http://www.homedepot.ca/product/eaton-whole-home-surge-protector/826426

http://www.homedepot.ca/product/eaton-electrical-surgetrap-whole-home-surge-protector/943213

I guess neither of these are going to be good for a lightning strike. CK, what is the cost of the SPU2 Surge Protection unit? Any whole-house surge protection that you would recommend?

 

[Captain Kilowatt]

I can't comment on the above units as I have never seen them before. The SPU2 I have is usually supplied with a Nautel broadcast transmitter. I have the unit because it was removed from a decommissioned tx site. IIRC however they went for around $4-500 back about 10-12 years ago. Not sure if you can just buy one direct from Nautel or not. They are made up here in Nova Scotia at the Nautel tx plant.The MOV's inside are about the size of a standard AC panel breaker....about an inch thick by two inches by three inches or thereabouts. I had one installed on an FM site that took a MINIMUM of five direct hits one storm........I watched it from a distance.....and all we lost were a bunch of diodes in the three phase power supply of the tube tx. The solidstate tx came back up fine after all the breakers were reset.

When it comes to lightning you need something rathe4 substantial and a simple power bar that claims lightning or surge protection probably won't cut it.

 

[DainBramage]

methinks his "alarm installer" is a "two wire electrician" (not a complement), I wonder if his alarm is connected to a TELCO line?

 

[Captain Kilowatt]

Just took a look at the units from Eton above. Still not sure about them. I see they are Mike Holmes approved LOL. I haven't seen them in the Home Depot down here but I have seen a unit by Siemens here at Home Depot. Couple hundred dollars and I was going to get it until this Nautel unit fell into my lap.

 

[Beetle]

Well, almost a hundred people have viewed this thread and only CK had issue with some aspects of it. I am not in total agreeance (yes, some may say this is not a word but I like it) ...

If the word you want doesn't exist, make it up!! Agreeance "is a perfectly cromulent word." Spoken by Miss Hoover, Lisa Simpson's teacher on some TV show.

 

[BettysNephew]

If anyone truly believes that any of the little boxes that generally consist of a couple of MOV's between the line and neutral and maybe line to ground can stop a voltage event that can rip across miles of free space as lightning does they are very sadly mistaken. They may help on a short duration line surge from the power company but lightning, I think not.

 

[Captain Kilowatt]

If anyone truly believes that any of the little boxes that generally consist of a couple of MOV's between the line and neutral and maybe line to ground can stop a voltage event that can rip across miles of free space as lightning does they are very sadly mistaken. They may help on a short duration line surge from the power company but lightning, I think not.

By the time it hits your electrical panel it is not the event that can travel across miles of free space. That is unless it strikes your electrical mast then all bets are off. Transformers etc along the distribution lines limit the surge and those decent quality MOV type suppressors can indeed handle those millisecond long voltage spikes of hundreds of volts over the line voltage. These spikes are very short duration and are effectively clamped to ground. You are not seeing millions of volts on the AC line. You are seeing several hundred or maybe a thousand or two volts of extremely short duration typically in the several microsecond range. As with everything, all such devices have their limits. You just have to know what those limits are.

LEA Is another decent supplier of lightning arrestors for AC lines as well as DC lines data lines etc.

http://www.smithspower.com/brands/transtector/about-us/smiths-power/lea

 

[Robb]

Just three letters:
E . . . M . . . P . . .

Even if you have everything grounded AND surge protected; there is no guarantee that the EMP alone won't take out circuitry.
Been there; done that . . .

NEC code uses/specifies an 8 ft ground rod.

 

[unit_399]

We get some really vicious thunderstorms in Colombia. Especially this time of year a biggie rolls through almost every night. If we ever suffer a direct hit to our house, I don't think any amount of protection devices short of the nautel unit CK has will do a bit of good. After losing our TV and home theater system to lightning-induced power line surges, I installed some Cornell-Dubilier surge boxes between the ac outlet and any high $$$ electronic equipment. Also, I installed a 130vac MOV across hot side to neutral on every AC outlet in our house. This stopped the primary side of the wall warts we use on things from opening up whenever there was a strong surge. cheap insurance.

- 399

 

[Klondike Mike]

...Today at 7:30 PM Last edited by a moderator: Today at 7:49 PM

 

[Captain Kilowatt]

Actually all I did was take Beetle's comment and move it outside the quoted text area so it would show up without expanding the quoted posts. He entered his comment mistakenly inside the quote fields and looked at first as if it was a simple quote without comment.

 

[Klondike Mike]

I came across this article expanding on "surge-type" whole house devices. Kind of bandied about "lightning" protection but I think not.

http://www.stevejenkins.com/blog/2014/10/whats-the-best-whole-house-surge-protection/

Looks like Mike picked a winner.

Canadian source (Lowes)
USA source (Amazon)

 

[Captain Kilowatt]

I came across this article expanding on "surge-type" whole house devices. Kind of bandied about "lightning" protection but I think not.

http://www.stevejenkins.com/blog/2014/10/whats-the-best-whole-house-surge-protection/

Looks like Mike picked a winner.

Canadian source (Lowes)
USA source (Amazon)

I think you are right. I finally had time to look a little closer at the Eton units. I am planning an addition to the house next year, an in-law suite for my parents, and may install those units on the panel. It will have it's own service entrance separate from mine. I dare say a direct strike to the power line outside the house would put any arrestor to task however most damage is from EMP induced voltage spikes from nearby strikes and this is where the type 2 and even type 3 units really perform well.