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Author Topic: New Load Bank  (Read 4140 times)

Tim McCulloch

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Re: New Load Bank
« Reply #20 on: March 15, 2018, 12:35:31 pm »

Thanks.... You will be the last one to go.

"It's a cook book!"
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"Practicing an art, no matter how well or badly, is a way to make your soul grow, for heaven's sake. Sing in the shower. Dance to the radio. Tell stories. Write a poem to a friend, even a lousy poem. Do it as well as you possible can. You will get an enormous reward. You will have created something."  - Kurt Vonnegut

brian maddox

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Re: New Load Bank
« Reply #21 on: March 15, 2018, 07:20:15 pm »

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brian maddox
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'...do not trifle with the affairs of dragons...

       ....for you are crunchy, and taste good with ketchup...'

Mike Sokol

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Re: New Load Bank
« Reply #22 on: March 15, 2018, 08:38:23 pm »

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Mike Sokol
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Mike Sokol

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Re: New Load Bank
« Reply #23 on: April 25, 2018, 09:34:23 pm »

Used my load bank in battle today and ran a really interesting test where I reversed the neutral and ground lines to test the EGCís ability to sink 45 amps of fault current. And I was able to find that it opened up after 1 minute of heating, but then slowly returned to continuity once it cooled down in 5 minutes. You canít get those kinds of results from an impulse test. You need steady state current.
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Ron Hebbard

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Re: New Load Bank
« Reply #24 on: April 26, 2018, 04:01:50 am »

Used my load bank in battle today and ran a really interesting test where I reversed the neutral and ground lines to test the EGCís ability to sink 45 amps of fault current. And I was able to find that it opened up after 1 minute of heating, but then slowly returned to continuity once it cooled down in 5 minutes. You canít get those kinds of results from an impulse test. You need steady state current.
4 Queries:  What gauge and material was the EGC?
How and where did it fuse or open?
What gauge was it at its narrowest point after it had cooled and regained conduction? 
Where would it fuse, and at what current, on a subsequent test?
Toodleoo!
Ron Hebbard.
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Mike Sokol

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Re: New Load Bank
« Reply #25 on: April 26, 2018, 09:33:12 pm »

4 Queries:  What gauge and material was the EGC?
How and where did it fuse or open?
What gauge was it at its narrowest point after it had cooled and regained conduction? 
Where would it fuse, and at what current, on a subsequent test?
Toodleoo!
Ron Hebbard.

I can't go into a lot of detail just yet, but this was an 8-gauge copper wire that was wire nutted onto a 12-gauge copper wire, and was then terminated in a standard bus bar in a service panel. I'll fill you all in on more details once I'm allowed, but this was interesting because an Ideal SureTest Analyzer showed the EGC impedance as perfect at around 0.5 ohms, but my Load-Bank test revealed a completely different failure mode I didn't predict. And there were several others witnessing it, so it's fully documented.
« Last Edit: April 30, 2018, 10:32:03 am by Mike Sokol »
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Mike Sokol
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Jonathan Johnson

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Re: New Load Bank
« Reply #26 on: April 27, 2018, 01:56:37 am »

I can't go into a lot of detail due to a pending litigation, but this was an 8-gauge copper wire that was wire nutted onto a 12-gauge copper wire that was buried underground, and was then terminated in a standard bus bar in a service panel.
I'll fill you all in on more details once I'm allowed, but this was interesting because an Ideal SureTest Analyzer showed the EGC impedance as perfect, but my Load-Bank test revealed a completely different failure mode I didn't predict. And there were several other EE's witnessing it, so it's fully documented.

Speculating here... it sounds like a case of an unforeseen problem in a design, and you were called to figure out what happened (kind of a failure analysis thing). Since there is "pending litigation" then maybe one party is trying to prove that the other party was negligent -- that "they should have known" this could happen. But maybe it couldn't have been predicted because the exact scenario involved failure modes that didn't fit the existing models.

That's just a guess. Maybe I'm out-of-turn here.
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Stop confusing the issue with facts and logic!

Mike Sokol

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Re: New Load Bank
« Reply #27 on: April 27, 2018, 04:59:56 am »

Speculating here... it sounds like a case of an unforeseen problem in a design, and you were called to figure out what happened (kind of a failure analysis thing). Since there is "pending litigation" then maybe one party is trying to prove that the other party was negligent -- that "they should have known" this could happen. But maybe it couldn't have been predicted because the exact scenario involved failure modes that didn't fit the existing models.

That's just a guess. Maybe I'm out-of-turn here.
I canít say any more right now. Maybe in 6 months. But Iíll draw up a hypothetical test situation next week. What I did was really simple but very easy to explain once you see it.
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Mike Sokol
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