lightening strikes

  • Thread starter Thread starter karambos
  • Start date Start date
K

karambos

New member
Can anyone tell me how to protect my gear against lightening striking the house? thx
karambos
 
Firstly, make sure you're running everything through a surge protector for starters. That is a given and will help against current spikes inherent in normal electrical grids. That should be ok for most users. If you want to be extra sure, you can get a UPS or something like that, which actually poweres your gear by a "battery" that regulates a consistent output voltage.
 
thanks for reply

thanks for the prompt reply, Octoruss.

I'll look into it straight away
 
A UPS is a great idea not only because it will keep power regulated, it will let your computer run for a few minutes after the power has gone out so you can save all of your work and shut down properly.
 
And don't forget to disconnect everything frothe wall when your done for the day if possible.

David Artis
 
And don't forget to disconnect everything from the wall when your done for the day if possible.

David Artis
 
In general, heed the advice of anyone from Florida, Oklahoma, Kansas or South Dakota. They have lightning storms the likes of which you've never seen before, and they'll certianly know what time of day it is.
 
Disconnecting all the gear is often not an option, simply because there is so much of it and its spread out throughout the studio. Like mine :)

We installed a long pointy rod on the roof and tied it to ground (Lightening rod) however this won't be too useful since the shortest tree near my house is a 200'+ walnut tree. Then there is the giant evergreen thats obviously on steriods, also next to the house.

I have the entire studio, meaning computers, servers, audio gear etc, on a hardwired UPS which is mounted in the basement. This feeds 100A cable that goes to the studio, and terminates at the back of a 80A isolation transformer, mounted in the crawl space on rubber pads. This in turn connects to a 60A breakerbox which then feeds the studio. 3 breakers, one for lighting, fans and air conditioing, one for computers, one for music gear.
 
Just make sure you have a good ground or any surge protection you use won't be effective.
 
karambos said:
Can anyone tell me how to protect my gear against lightening striking the house? thx
karambos
Click to expand...

If a bolt actually hits your house you will be F**ked! Surge surpressors may work great when lightning strikes someone elses house or a poll/transformer in the neighborhood, but at YOUR house, nothing is going to stop it from going everywhere. Get insurnace.

A bolt of lightning with enough potential to travel hundreds of feet from the sky to ground is not going to be stopped or diverted by less than a gap / insulator with resistance equal to hundreds of feet of air. It goes into the film on the back of mirrors, chicken wire in stucco, pipes, all wiring, anywhere there is metal. A little transorb would not be quick enough to stop, or conductive enough to divert that kind of power and voltage.

We used to put the grade crossing controls on RR tracks. We used large spark gap protectors rated at hundreds of amps. A close enough hit would vaporize the protector, and all the downstream equipment. I mean vaporize it!!!

Lightning rods can sometimes divert current away from a house, but the ones we put on radio towers on the top of hills are wired into a grid of burried cable and 8' copper rods to handle the current. An antenna on the roof with one #10 wire to a water pipe will not divert a lighning bolt for long.

Get insurance!

Phil Abbate
Registered Professional Electrical Engineer.
 
I don't know if this is really true, but my builder (whom I do trust implicitly) claims that the cheaper the surge protector, the better the protection from massive surges. His logic is that the cheap ones act like a big fuse and fail quickly at the first pulse of that first big wave of excessive current. Sure, the surge protector is shot, often melted in the process, but the precious gear tends to have a much higher survival rate. The more deluxe protectors endure the surge better, but at the cost of passing it along to the delicate downstream components.

It has a perverse appeal to it.
 
Todzilla said:
I don't know if this is really true, but my builder (whom I do trust implicitly) claims that the cheaper the surge protector, the better the protection from massive surges. His logic is that the cheap ones act like a big fuse and fail quickly at the first pulse of that first big wave of excessive current. Sure, the surge protector is shot, often melted in the process, but the precious gear tends to have a much higher survival rate. The more deluxe protectors endure the surge better, but at the cost of passing it along to the delicate downstream components.

It has a perverse appeal to it.
Click to expand...

Perhaps on a power line hit he is right. The smaller transorb may short and blow the internal fuse stopping the surge. I am talking about a direct hit of a bolt on your house. Forget it nothing is going to stop that from going anywhere it wants.
 
Most surge protectors aren't all that effective against lightning. The two basic types I've had dealings with, MOVs (metel oxide varistors) and Gas Filled Diodes just aren't fast enough to catch a hot strike (they run through them like shit through a goose). You need something like a ferroresonant transformer (a line conditioner).
 
I will not plug in one piece of gear during a lightning storm! This time of year in Miami we have lightning storms every afternoon. I record in the A.M., and if I hear ONE lightning strike, everything gets shut down.

Bob
 
living in the subtropics like Bob we get lightning storms but as I'm on solar I don't have to disconnect BUT I always disconnect my phone as I've blown a few modems. :)

cheers
John
 
John Sayers said:
living in the subtropics like Bob we get lightning storms but as I'm on solar I don't have to disconnect BUT I always disconnect my phone as I've blown a few modems. :)

cheers
John
Click to expand...

I hear you guys.

I just refuse to cut down the 200' evergreen next to the house. I figure it will be hit first, and all the cheap MOV's all over the place might blow and save me.

If not, like Phil suggested twice, I have insurance.

Since my house has a steel girder frame, plaster over chicken wire, metal gutters and leaders, I will have to concede that my newly installed lightening rod was a waste of $200 while amusing for my electrical contractor who didn't really know what to do with it at the time :)

Lets here it for insurance and really tall pine trees!!!
 
Lightning. I live south of Denver, on the top of a ridge, in the area that has the second highest incidence of lightning strikes in the US (highest is the Tampa Bay area). I also run a business from home that is based on an absurd number of computers at its core, in addition to the studio hardware downstairs. I have to take it seriously, because one stroke could absolutely put me out of business. So I went just about as far with it as the folks who install transmitter facilities on isolated hilltops have to go, right down to doing the ground radials. You'll like this, Phil!

The first thing we did when moving here was contract with a licensed lightning protection system specialist, and have a proper set of power entry point lightning suppressors and a lightning rod system installed. There *are* UL approval procedures for on-site lightning protection systems, and approved installers. If you live in a high-lightning area, seek them out! After the installation (11 lightning rods, 340' of 1/2" copper ground bond cable, four 20' ground rods, and the power entry point protection), the UL inspector came out and gave us a "UL Approved" sticker. For the *house*. This I found amusing at the time...

The next thing I did was to install major-league UPS systems for all the computers, including the studio DAW and HDR. My thought was not only that the UPS would hold up the power in case of failure (which happens altogether too often around here), but also that the UPS would give its life to save the downstream gear on a direct strike. For really critical equipment, like my server farm, the machines are plugged into a MOV/gas-tube suppressor that is then plugged into the UPS. So that's three tiers of MOVs: the power entry, the ones built into the UPS, and the strip. Belt-and-suspenders...

The server room also has its own safety ground system that is carefully isolated from the lightning protection ground, and all the electrical safety grounds are bonded to it with the lowest possible inductance interconnect (wide, fat, minimum possible number of bends).

The last thing I did is install MOV/gas-tube/avalanche-diode suppression on all incoming phone lines at the phone cabinet. I also installed avalanche-diode suppression on all the internal phone extensions, and on all Cat5 ethernet runs (yes, they do make suppressors that can do 100baseT). The reason for protecting the internal lines is that a nearby strike produces enough EMP to induce voltages in the lines that can damage ethernet switches and phone PBX exchanges, _even without having a direct strike on the gear_. This is important: mutual inductance is not your friend. The field strengths surrounding a stroke are absolutely mindboggling.

In 4 years, we've had one direct strike on our rod system, luckily a fairly mild one. We lost one power strip, two Cat5 suppressors, one phone extension suppressor, and *no* computers, disk drives, routers, phone switches, or studio gear. A funny example of the power involved: the stroke was on the living room chimney rod, and I had to go out afterwards and pound the nails on the chimney cladding back in. The magnetostriction from the stroke's EMP backed them out about half an inch in the vicinity of the ground bond cable. It also burned the pointed conical tip of the 1/2" aluminum rod off to an irregular 1/2" ball... No, I'm not making this up. Any questions about how much energy we're talking here?

Even so, lightning is completely capricious and unpredictable. Eventually, we'll probably take a hot strike in the wrong place and lose some gear- but I still think I'm well ahead of the game. We're well protected against indirect strikes in the vicinity, which happen all the time in a normal year, and IMNSHO the investment has been worth it. The view we have makes up for the risk!

You just flat can't do realistic, functional lightning protection on the cheap. If you need it, it's going to cost money, and even so it'll never be perfect- but it *can* be done.

And I also have very good insurance. Belt and suspenders... (;-)
 
I just have to laugh! My entire "studio" runs off one 20 amp line! Definetly not "Designed By John Sayers"!:D

Bob
 
Skippy, I work in a telephony headend all built to Bellcore specification I have an 8' ground rod drivin every ten feet around the parimeter of the room all bonded with cad weld to 00 cable to a master ground buss bar. Every rack and individual piece of equipment is bonded to this ground ring with #6A 600 amp UPS and a -48VDC system with an A and B battery strings (27,000 lbs of batteries in each string). Lots of surge suppression around here.
 
You must log in or register to reply here.
Back
Top