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Discussion Starter · #1 ·
Every day this week I spent correcting hum/noise issues a different locations, mega church, TV Studio, Apt building, data center, but this afternoon I got a emergency call site (SECURE SECRET) had a HOT NEUTRAL, as I drove there I figured out the issue.

Sure enough ungrounded motor generator and A phase branch circuit was shorted to ground resulting in A phase to ground 0, B phase to ground 208, C Phase to ground 208, neutral to ground 120 VAC. This was the prettiest panel installation I have ever seen, NEAT, VERY NEAT artist NEAT. But still WRONG the system has been on line 5-6 years and NEVER GROUNDED.
Not only that they STRESS Grounds are everything to them , ISO GND, EGC's yada yada yada....BUT WRONG.
 

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Sure enough ungrounded motor generator and A phase branch circuit was shorted to ground resulting in A phase to ground 0, B phase to ground 208, C Phase to ground 208, neutral to ground 120 VAC. This was the prettiest panel installation I have ever seen, NEAT, VERY NEAT artist NEAT. But still WRONG the system has been on line 5-6 years and NEVER GROUNDED.
Not only that they STRESS Grounds are everything to them , ISO GND, EGC's yada yada yada....BUT WRONG.
Shorted to ground, or intentionally grounded? How does stuff like this even happen? :blink:
 

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Discussion Starter · #3 ·
Secure rooms referred to as skiffs sometime utilize motor generators a 100HP motor that is coupled to a generator. This permits truly isolated separately derived power. The thought being that a direct connection to the utility would let some devious folks listen to what is being typed on a keyboard. Supposedly all typewriters and keyboards have a signature that can be picked up by "SPYS" listening and decoding the utility power.

What they had was a ungrounded 3-phase 4-wire wye no neutral ground bond. Something happened to an A phase branch circuit resulting in a connection to ground. At this point (not sure how) someone figured out (Possible ground alarm on the PDU) that there was 120 VAC between the neutral and ground.

The old saying that a phase short to ground on an ungrounded system is free the second phase fault is a phase to phase fault.
 

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Secure rooms referred to as skiffs sometime utilize motor generators a 100HP motor that is coupled to a generator. This permits truly isolated separately derived power. The thought being that a direct connection to the utility would let some devious folks listen to what is being typed on a keyboard. Supposedly all typewriters and keyboards have a signature that can be picked up by "SPYS" listening and decoding the utility power.

What they had was a ungrounded 3-phase 4-wire wye no neutral ground bond. Something happened to an A phase branch circuit resulting in a connection to ground. At this point (not sure how) someone figured out (Possible ground alarm on the PDU) that there was 120 VAC between the neutral and ground.

The old saying that a phase short to ground on an ungrounded system is free the second phase fault is a phase to phase fault.

I have done many gov. jobs where we installed filters on the phases coming into a building to avoid spying on the lines. Have yet to do a building that uses generators to avoid the problem.
 

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Discussion Starter · #5 ·
I have tested a lot of those filters, and by far the more common way to protect a skiff.
 

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I have tested a lot of those filters, and by far the more common way to protect a skiff.
I have a buddy who's was working at Ft.Detrick where they're doing an entire building to operate as a SCIF. They do all that biological warefare stuff at Ft. Detrick. I don't think he's there now, but I should ask about how they did or were planning the incoming power.

Were you at the Sycamore facility, by chance?
 

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I have a buddy who's was working at Ft.Detrick where they're doing an entire building to operate as a SCIF. They do all that biological warefare stuff at Ft. Detrick. I don't think he's there now, but I should ask about how they did or were planning the incoming power.

Were you at the Sycamore facility, by chance?

Classic SPY tactic;
divulge some information to try and gain more :laughing:
 

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Discussion Starter · #9 · (Edited)
I've worked at most of them but this was an a 4 story office building in the Washington suburbs.

Movies are made about the dangers of places like Detrick. Several years ago I worked at a place with mice, rabbits and monkeys, no one ever explained what they did there (and I have a bad habit of asking). About 2-3 years later this place is on 60 Minutes, monkeys got out and contaminated the place with Ebola ( I think it was Ebola). They abandoned the building and the management company rented part of the building to a day care center. BIG Story locally and nationally.

Always wondered how to spell SCIF, which in govermenteze and most likely is an acronym for Sensitive Compartmented Information Facility (oh the wonders of the web)
 
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