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110v Dropped power to entire building?

1528 Views 22 Replies 8 Participants Last post by  dmxtothemax
We have a 3 phase 208V Machine(connected to overhead bus) with a 220v/110v step down transformer inside the cabinet that powers a 110v receptacle outside the cabinet.(Very old Machine and no electrical Prints).

Today... Someone decided to plug another machine into that receptacle with a Defective Start Capacitor (Currently they hand turn the motor to get the motor going, and I tested the Cap.). As they turned on the machine all 3 phases seemed to drop out. As all the lights and machines turned off in the building. Has anyone ever heard of this? I am reluctant to test it out again to see if it's just a coincidence. Because, it created a lot of problems for us with the servers and Fire Suppression system as they are ran on two different legs.

No Breakers, fuses, tripped anywhere in the building and No reported power outage in the area(That I know of). Weather was calm. Power was down for about 15 seconds and came back on its own.

I looked in the machine cabinet, it does have 40 amp fuses on the Machine Disconnect and 15 amp fuse on the secondary side of the step down transformer.

Has Anyone heard of this happening before is this just a Coincidence? I won't be able to get back to that machine for at least a couple of weeks to create an electrical diagram for it. But if anyone had this happen to them before would be helpful. As in my 15 years I have never had this happen to me before. (For now I just slapped a do not use tag on the receptacle).

Most of these machines are built in the 80's and 90's with some modifications. I have found Lead side switched and Neutral side Switched and same goes for fuses. Any wiring mistakes you can think of, is very likely at this point.
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Welcome @Dutchy to the forum.

Are you an electrician? Please take a few minutes to fill out your profile as per the user signup agreement.

Sent from my new phone. Autocorrect may have changed stuff.
 

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Also with 120/208 volt 3 phase bus distribution why would there be a 220 to 110 step down transformer? Secondly why with three phase available would you be using a single phase motor with a faulty start cap to begin with?


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Also with 120/208 volt 3 phase bus distribution why would there be a 220 to 110 step down transformer? Secondly why with three phase available would you be using a single phase motor with a faulty start cap to begin with?


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It may not have a neutral going to it... I wonder if OP is an electrician though... @John Valdes

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Possible, but I haven’t come across that rarely if ever, but there are people that’ll surprise you if you let em. That’s the whole advantage of a 120/208 Y distribution system. Oh well I’m intrigued enough to watch the train wreck unfold.


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It may not have a neutral going to it... I wonder if OP is an electrician though... @John Valdes

Sent from my new phone. Autocorrect may have changed stuff.
He's not. He may need to call an electrical contractor.
 
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If the power restored without any interaction on your part it seems like a temporary outage. It's really hard to say not being there to look at the system. Was the rest of the building effected or was it just the lights and machines in the area? Ask your neighbors if they had a power bump.
 

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Discussion Starter · #9 ·
Before my time, I think someone moved the overhead disconnect from the 220v Bus to the 208v Bus. They have both in the building.

The machine with the faulty cap apparently has been like that for years. Built in the 80's and still has the original manufactures single phase motor. I am not exactly sure what size motor it is, as there is no name plates on any of the machines or motors.

I filled some of my profile out.
 

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I would tend to agree, as no current limiting devices tripped or burned up, I’d have a hard time believing plugging something in would drop everything and then just come back up on it’s own. No breakers tripped or fuses blown etc.


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Interesting.

Nearly as interesting as why the ups units, back-up batteries for the servers and fire suppression system didn't work.

As 99.99 percent of places don't have self resetting hardware i would have plugged it back in for fun.
 

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Interesting.

Nearly as interesting as why the ups units, back-up batteries for the servers and fire suppression system didn't work.
Maybe because they haven't been checked since the '80s (if they have them). :vs_laugh:
 
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We never were allowed to test or cycle or pull maintenance on anything in our Data Centers. Even with redundant systems, it was so rare that the only time it was tested was when something took a dump. I don’t get it these Data Nerds think that they know all about Facilities and Electrical infrastructure. One too many Site Uptime, and BICSI seminars.


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We never were allowed to test or cycle or pull maintenance on anything in our Data Centers. Even with redundant systems, it was so rare that the only time it was tested was when something took a dump. I don’t get it these Data Nerds think that they know all about Facilities and Electrical infrastructure. One too many Site Uptime, and BICSI seminars.


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You need our poco we get to test ours 4-5 times a day unless it rains then we test it every few minutes.

Looking on the weekly board at one site and it showed 26 brown outs, 14 generator start-up so far this week.
 

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Possible, but I haven’t come across that rarely if ever, but there are people that’ll surprise you if you let em. That’s the whole advantage of a 120/208 Y distribution system. Oh well I’m intrigued enough to watch the train wreck unfold.


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I have seen this many times on a 208/120 4-wire they set a control power transformer 208 to 120.

Best Guess

Everything else he posts seems to be FM (F'ing Magic) UNLESS someone accidentally opened an upstream CB or switch and won't admit it.
 

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ComEd’s grid is pretty good at our facility. Our preferred source line only seemed to be a problem during really bad storms. When things fluctuated too much the Caterpillars took all the critical loads. Our breakers were set for make to break transition and back fed for a few cycles so the UPS systems weathered things pretty smoothly.


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Discussion Starter · #17 ·
Unfortunately our neighbors are closed due to the corona virus shut down.

The severs and fire suppression systems currently seem to have omitted the battery backups or surge protectors during the design process.
 

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Everything else he posts seems to be FM (F'ing Magic) UNLESS someone accidentally opened an upstream CB or switch and won't admit it.

FM is when you discover that one buss is a clean power supply/UPS and the other is for the machines, lights, etc.

post 9#
"Before my time, I think someone moved the overhead disconnect from the 220v Bus to the 208v Bus. They have both in the building."
 

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A generator by itself is not much of an up system. Do you have battery rooms and ATS's that work properly? Or do you have any Batt backup? Did you get any codes or messages from your UPS ? It might take 15 seconds for a good generator to stabilize. Maybe your UP's is down. Big ones require expert to do repairs. ( Guys that work on them daily ) I have never worked on a large ups but the messages come in helpful when your on the phone to China.
 

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Discussion Starter · #20 ·
A generator by itself is not much of an up system. Do you have battery rooms and ATS's that work properly? Or do you have any Batt backup? Did you get any codes or messages from your UPS ? It might take 15 seconds for a good generator to stabilize. Maybe your UP's is down. Big ones require expert to do repairs. ( Guys that work on them daily ) I have never worked on a large ups but the messages come in helpful when your on the phone to China.

Have none of that.(But will be addressed soon).

I did follow the conduit to the 208v bus drop on that machine though.

I am going to call an electrician in, to move the line to the 220v Bus as it should never be their in the first place.

I just started here a month or so ago and I walked into a CF (Cluster F**k)
 
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