Ad
Ad
Ad
Pages: « 1 [2]   Bottom of Page
Print
Author Topic: Uninterruptible power supply units: 1500 watt: recommendations?  (Read 2990 times)
BobDavid
Sr. Member
****
Offline Offline

Posts: 1077


« Reply #20 on: January 06, 2014, 08:42:53 PM »
ReplyReply

Hey Steve, thanks for the heads-up about the APC factory outlet. Go figure...
Logged
Steve Weldon
Sr. Member
****
Offline Offline

Posts: 1460



WWW
« Reply #21 on: January 06, 2014, 10:57:04 PM »
ReplyReply

The place where the lightning struck was at ground, four inches above the coax cable and a pvc irrigation pipe. A six inch section of both the pipe and the coax were completely vaporized. A few of my friend are EEs; they used the the term plasma. Would that be the same as EMF pulses?
I've lived a number of years in Pensacola and can well remember the lightening storms there.   I'm a ham operator and this was one fo the most challenging places to protect the antennas and gear indoors.  We'd go so far as to have different ground fields for power and signal.  Most of the ground systems in homes that I've seen are almost like an afterthought to the main power block.  A good ground is expensive, especially in sandy soil like we had in Pensacola (and likely in Tampa as well?) often requiring a series of ground rods sunk as much as 21-28 feet to adequately route a lightening strike.. And copper ain't cheap these days.. Smiley 

I've seen lightening hit in the trees 20-30 feet from the house and that was enough to energize the ground rod system where the power would then go up the 00 gauge ground wire into the house to the equipment bench where I had a 1/4 inch thick by 2 inches tall by 6 feet wide on standoffs from one side of the bench to the other.  The chassis of all equipment on the bench had a 1/2 inch braided copper wire to a big clamp.  When operating these clamps were connected to the ground bar.  And each piece of coax coming from a signal source (antenna) would go through a gas charged arrestor that was grounded to the same bar.   The ground field outside that the ground bar was grounded through was 6 21 foot deep 3/4 thick rods all connected through the 00 gauge copper ground wire.  Anyway, when a storm hit we'd pull the clamps off the ground bar totally disconnecting the outdoor ground from the equipment.   With that hefty system I was pretty sure I was good to go.  The first time I storm hit lightening hit the trees to the sandy soil, was picked up by the ground system, and fed back into the house and into the ground bar.  With no where to go the lightening jumped from the ground bar to the clamps hanging free over 2 feet away!  Another got the metal bottom of my chair.

This sounds like what happened to you in a basic way.  Electricity, depending on the power involved, can jump distances that would surprise most.

We called up the company that measured my soil and certified 21 feet was deep enough.. they told me the toasted gear, chair, etc, was a 'residual' power strike, that the main part went down the rods to ground. Hmm.   Always hard to tell.  We sunk them another 14 feet (one fits in the other so you can keep adding more and airhammer them down) and never had an issue in the next 8 years I lived there.

With such a close hit.. you could have had cables on the other side of the room and it still would have jumped.    That lightening rod system starts to sound cheap on a permanent residence..
Logged

----------------------------------------------
http://www.BangkokImages.com
Steve Weldon
Sr. Member
****
Offline Offline

Posts: 1460



WWW
« Reply #22 on: January 06, 2014, 10:58:05 PM »
ReplyReply

Hey Steve, thanks for the heads-up about the APC factory outlet. Go figure...

A pleasure.  Often what they sell at the Outlet is a sales year behind.. but so what..
Logged

----------------------------------------------
http://www.BangkokImages.com
degrub
Sr. Member
****
Offline Offline

Posts: 275


« Reply #23 on: January 06, 2014, 10:59:53 PM »
ReplyReply

Straightforward explanation of what happens in a lightning event
http://science.howstuffworks.com/nature/natural-disasters/lightning.htm
and why MOV surge protectors don't work.

Frank
« Last Edit: January 06, 2014, 11:03:22 PM by degrub » Logged
Steve Weldon
Sr. Member
****
Offline Offline

Posts: 1460



WWW
« Reply #24 on: January 06, 2014, 11:30:44 PM »
ReplyReply

Straightforward explanation of what happens in a lightning event
http://science.howstuffworks.com/nature/natural-disasters/lightning.htm
and why MOV surge protectors don't work.

Frank

Metal Oxide Varistor's cost about 15 cents each.. and what's great about them is you can put one in a  50 cent 6 outlet "thingy" and now it has a name.. "surge protector."  But the best part is you can now sell it for $25.  $150 if you're Monster Cable.

There are actually two main reasons they don't work.  1.  They don't react nearly fast enough (they they are useful certain kinds of "surges" but never "strikes").  2.  MOV's need a good ground to work and most house grounds are inadequate.
Logged

----------------------------------------------
http://www.BangkokImages.com
Pages: « 1 [2]   Top of Page
Print
Jump to:  

Ad
Ad
Ad