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#129028 - 07/02/04 06:36 PM Lightning problem  
ayrton  Offline
Member
Joined: Dec 2001
Posts: 201
Pa
Township building called. Been having problems with computers and equipment blowing out during thunder storms. They have just been replacing the equipment.
Checked the service today, and they have a ground rod, two as a matter of fact. only about six inches apart though, in the building driven through the concrete floor.
Need some advice and ideas how we can possibly do anything for them.
Police station is also in the building and there equip damaged as well.


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#129029 - 07/02/04 06:37 PM Re: Lightning problem  
ayrton  Offline
Member
Joined: Dec 2001
Posts: 201
Pa
This kind of backs up my thoery that ground rods dont do ****


#129030 - 07/02/04 10:48 PM Re: Lightning problem  
Ron  Offline
Member
Joined: Mar 2002
Posts: 582
White Plains, NY
Lots of possibilities.
Ensure good grounding electrode system (it does help with lightning). Provide multi levels of TVSS throughout the building of appropriate ratings. Provide a UL Master Label lightning protection system on the structure.


Ron

#129031 - 07/02/04 11:06 PM Re: Lightning problem  
ayrton  Offline
Member
Joined: Dec 2001
Posts: 201
Pa
TVSS?


#129032 - 07/02/04 11:18 PM Re: Lightning problem  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
No offense is meant, but be cautious about statements on grounding-electrode quality based on anecdotal opinion. Lighting damage is partially a statistical issue. Sometimes close-in hits cannot be defended with any amount of protection.

Does the building have an NFPA-780 system in place? What kind of surge protection is installed at the building electric-service entrance and telephone-cable entrance? Is the AC-power system, telephone-entrance protector, metal piping, lightning protection and foundation steel interconnected with low-reactance conductors? Bonding to limit {fast-transient} potential difference between these components/systems within and external to the building is a crucial part of efforts to resolve the problem.

If this is starting to cost the municipality significant money, a reputable lightning-protection engineering firm may need to make recommendations on acceptable protection practices based on national-consensus standards and their experience in the geographic region. There are likely no quick or cheap solutions.

A dated but respected general guide on surge fundamentals is www.itl.nist.gov/fipspubs/fip94.pdf
and reams of other non-vendor-based data
www.eeel.nist.gov/817/817g/spd-anthology/
www.jsc.mil/jsce3/emcslsa/stdlib/docs/Handbooks/Mil-HDBK-419A-V-1&2.pdf
www.e-publishing.af.mil/pubfiles/af/32/afi32-1065/afi32-1065.pdf ]http://www.armymars.net/ArmyMARS/Safety/Resources/grounding.pdf]




[This message has been edited by Bjarney (edited 07-02-2004).]


#129033 - 07/03/04 06:29 AM Re: Lightning problem  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
TVSS

Transient Voltage Surge Suppressor


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#129034 - 07/03/04 07:30 AM Re: Lightning problem  
winnie  Offline
Member
Joined: Sep 2003
Posts: 649
boston, ma
Well outside of my domain of experience, but I am quite curious and have several questions. While the service has ground rods, is the grounding electrode system properly bonded to all other 'ground electrodes', eg. building steel, underground piping, etc.? Also, given that this is a township building with police, are there external communications antenna and the like? What is the grounding on these, and are the various ground systems bonded together?

-Jon


#129035 - 07/06/04 03:29 PM Re: Lightning problem  
ayrton  Offline
Member
Joined: Dec 2001
Posts: 201
Pa
As far as I can tell the building has no surge protection or lightning aresstors.
I have always been skeptical of the surge protection you buy anyway. I dont want the embarrasment of installing surge protection which will not solve the problem anyway.
No one has convinced me these things work.
I have many commercial accounts, some of whom have surge protection, and I have still seen equip fried, from PoCo surges or storms. UPS systems with surge protection in them also seem to come up short on protection.
If lightning hits a power line or tfmr, I cannot see anything stopping that surge into the service if it so desires to do so.
Getting a "lightning protection engineering firm" sounds almost amusing. I did not know such co's existed.
I would imagine it is very pricey.
This is a municipality with not much of a budget. We are in the year 2004 and they dont even have a backup generator, and this place is the "emergency shelter" area in the event of a catastrophe.


#129036 - 07/06/04 09:29 PM Re: Lightning problem  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
Keep routinely replacing stuff piecemeal, but your client may get tired of doing that and magically find funds to invest is an overall less-expensive, longer term fix. If you do a little footwork and offer a studied opinion on the matter, it could be cash in your pocket. If not, then it might be cash in a competitor’s pocket.


#129037 - 07/06/04 09:37 PM Re: Lightning problem  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
There’s gotta’ be something to resolving the problem, or NIST and the US military would not have already spent many millions and maybe a century trying to understand the problem.


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