Lightning tripped all breakers?

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jeffhornsby

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Location
Destin, FL
The location of the breakers

The location of the breakers

You said that no other breakers tripped in the individual buildings. Are the individual buildings close to the panel with the tripped breakers? We are investigating a couple of fires caused by flexible gas pipe due to lightning and the outcome of cases are determined if it was a direct strike. On one the cases lightning appeared to have struck the chimney on a two story house, and only three breakers were tripped and each of the tripped circuits were routed near the chimney. Also the fire did not start near the chimney.
 

hockeyoligist2

Senior Member
mxslick

mxslick

The test results came in while I was on vacation, so I don't know what the actual results were. I ran in to the Eaton guy today and asked him about it. He said that he performed an AC high pot on the breakers and that they checked out OK. He said that damage usually occurs if you do a DC high pot on vacuum breakers but not with AC. I don't know enough about it to ask more questions. If you have some I will write them down and ask him the next time I see him.
 

zog

Senior Member
Location
Charlotte, NC
Now everything has changed, these are MV Vacuum breakers? I thought we were talking about 480V breakers like the picture you posted. Which is it?
 

hockeyoligist2

Senior Member
zog said:
Now everything has changed, these are MV Vacuum breakers? I thought we were talking about 480V breakers like the picture you posted. Which is it?

Sorry, I just posted a pic I had on my PC. The residential guys seemed to think it was a panel breaker. They are Eaton 22500v breakers.
 

zog

Senior Member
Location
Charlotte, NC
hockeyoligist2 said:
Sorry, I just posted a pic I had on my PC. The residential guys seemed to think it was a panel breaker. They are Eaton 22500v breakers.

In that case you are barking up the wrong tree, the breaker has nothing to do with it at all (However, AC hipot is one of the tets to be done on VCB's, nothing wrong with a DC hipot on VCB's either, the techs are thinking about MV cables that can be damaged by DC hipot).

The relays is what you need to be looking at, first thing, are they electromechanical or microprocessor based relays?
 

hockeyoligist2

Senior Member
zog said:
In that case you are barking up the wrong tree, the breaker has nothing to do with it at all (However, AC hipot is one of the tets to be done on VCB's, nothing wrong with a DC hipot on VCB's either, the techs are thinking about MV cables that can be damaged by DC hipot).

The relays is what you need to be looking at, first thing, are they electromechanical or microprocessor based relays?
microprocessor based
 

zog

Senior Member
Location
Charlotte, NC
hockeyoligist2 said:
microprocessor based

OK, now this is making more sense. Your relays probally have some sort of ZSI feature (Zone Selective Interlocking) that made the feeders all trip but not the main(s), if you had a UV condition(Low voltage sondition but not low enough to iniate a UV trip on the mains) that can cause an overload on all feeders and mains (A load draws whatever power it is supposed to, if voltage decreases, current increases) , what happens is that before the mains trip they first "ask" the feeders if they have a trip signal also, if they do then the feeders trip but the mains dont because the mains are just protecting the switchgear line up, not the loads.

Sounds to me like your system did just what it is supposed to, and sorry to say, you wasted money testing the breakers. But hey, they should be tested every 3 years or so and you have that taken care of now (Silver lining).

Are these SEL relays (Schwitzer), Basler, or something else?
 

hockeyoligist2

Senior Member
zog said:
OK, now this is making more sense. Your relays probally have some sort of ZSI feature (Zone Selective Interlocking) that made the feeders all trip but not the main(s), if you had a UV condition(Low voltage sondition but not low enough to iniate a UV trip on the mains) that can cause an overload on all feeders and mains (A load draws whatever power it is supposed to, if voltage decreases, current increases) , what happens is that before the mains trip they first "ask" the feeders if they have a trip signal also, if they do then the feeders trip but the mains dont because the mains are just protecting the switchgear line up, not the loads.

Sounds to me like your system did just what it is supposed to, and sorry to say, you wasted money testing the breakers. But hey, they should be tested every 3 years or so and you have that taken care of now (Silver lining).

Are these SEL relays (Schwitzer), Basler, or something else?

They are Cutler Hammer. The Eaton guy said the system did just what it is supposed to do and it was time for a test anyway. Thanks!
 

ohm

Senior Member
Location
Birmingham, AL
As weress pointed out this is typical in a large facility. When I started at an industrial facility the instrumentation foreman asked me what I wanted him to do with the tapes from the event recorder he had rented three years ago.

I reviewed them and found thousands of volts were riding in on our 480v power every day and during a storm spikes jumped tenfold.

I read that because of the nature of house wiring (inter-electrode capacitance, gaps in devices etc.) such surges clamp to around 600V and don't usually do much damage.

Anyone concur?
 

mxslick

Senior Member
Location
SE Idaho
Always worth the effort...

Always worth the effort...

zog said:
Well, I guess I typed all that for nothing. Hope someone else out there got something out of this thread.

Dude, your responses are always informative, I love learning more about MV equipment, so don't think your efforts are wasted. :)

Thanks!!
 
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