During my years of studying electrical circuits and transformers, I learned about how in a 240/120 volt feeder to a home, if you get an open neutral wire on your mains, you can get 240 volts across your 120 volt loads, potentially damaging connected loads rated at 120 volts. Well, I have now seen it and confirmed that it can happen. I had a situation on a pump house feeder that had on open neutral and the phase voltage was 215 to neutral. In this case there was no 120 volt circuit really, it was a 3 phase pump, but the mains hot conductors all read 215 volts to ground (on a 3 phase 208/120 service.) The grounded neutral also serves as the grounding conductor for the system, so it was dangerous if a fault occurred with no return for the fault current to open the fuses. The faulted neutral was underneath a condo foundation installed years earlier. I had to by pass it and restore the line.
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I had a call to look at a pump controller this afternoon. I actually wired it a year or two ago. No big deal, just a 480 volt system powering an irrigation system and pumping water to a center pivot system. I opened the control 'smart box' up to begin looking for the reason it would not start the pump. I looked things over and began poking around with my meter taking some test readings of the voltage. Somehow, while I stuck my meter leads into a couple wire nuts to see what I had for voltage, I got nailed! Bang, right through the chest! I jumped hard and it really pissed me off pretty bad! I don't even see how I touched anything is what bothers me! I guess I touched my meter tip somehow that was in contact with the power.
I really have to be more careful. I am so used to going into these hot panels, and do it so often that I forget how dangerous it is! I worry that now that I'm older I could stop my heart! I wonder what it does to my heart and nerves when I get shocked like that? I was fine and everything, but I hope this doesn't keep happening! I'm going to have to knock this crap off! I can't afford to die yet!  Got shocked pretty hard today working on a center pivot. Made some mistakes and took a short cut and got nailed. I could have really gotten hurt, I wasn't. I've got to stop working stuff hot. The reason you work it hot is so you can check things with power and find out what the problem is, it's not the same when the power is off. I really got lucky today. I keep getting lucky and I think somebody's watching out for me. What really makes me mad is that I have a pair of hot gloves rated for 1000 volts, they were sitting in the truck! I'm going to start using them when I'm working a hot panel. It could be the difference between life and death. I was in a hurry to get to the next pivot appointment I had and didn't want take the extra time to turn off the power so I just worked it hot. I do this a lot. This time my hand brushed up against something I didn't even see. It could have killed me, I took it right through the chest. Worst case scenario for sure. If I would have slid down the ladder I would have really gotten hurt. If I had fallen off the pivot I'd have really gotten hurt. If my heart would have stopped....well, not good. I don't know if the farmer watching me knew CPR or not. I have a dangerous life, that's all there is to it.
 I was working on the pump control panel the other day and made a rookie mistake. What had happened was the motor that was fed from this circuit had burned up, that's why I was there, to determine what had happened.
In doing so, I was focused on the old motor that had been unhooked and moved aside, and a spare had been hooked up to the panel and was running. The old burned motor was sitting on the ground next to the motor and pump that were running. So, Since the old motor was removed and unhooked, in my mind the panel was dead and powered off. That was a major mistake! It was hot and running the other pump! In the photo to the left, you see the 'E68' number stamped on the overload heater, and the screw hole? I reached in and put my screw driver tip on the screw, and then reached in with my left had and grabbed the screw driver shank to guide it onto the screw. It was hot 120 volts and began arching as the screw loosened up. BUT I NEVER GOT SHOCKED! I realized what I had done and couldn't figure out why? I put my meter on the screw driver and to ground and sure enough it was hot, 120 volts. I was standing right there on the dirt and never felt a thing. I should have taken a good jolt, but didn't. So you say, "you weren't grounded through your shoes". Well, I was grounded. I always conduct and get shocked when this happens. Not this day, not one tingle at all, nothing! The ground around there was not that dry either, it was actually moist. I really feel I had a Guardian Angel that day, I truly do!  Well, it's the end of the 2014 ski season, and it's been a great one! I have had no major issues, aside from one touch screen failure on the 6-passenger lift all season! That's better than most years believe me. Usually I get several issues that require much attention and research. So I'm quite happy to see it end like this!
 Well, we're opening for Thanksgiving for the first time in...I can't remember how long! We've got great snow and last week's snow storm dumped about 3 feet! Looking good!
 Had my lift inspection this past week, during a snow storm! The mountain looked good though. We're off to another winter season. We're trying to get lift 1 open for Thanksgiving! It just may happen too, with what Mother Nature brought, plus snow making, it could happen.
 We had a power outage due to a couple of blown high voltage cutouts (fuses) on the 12,460 high voltage line at the ski area. I'm working with a lineman to replace the fuses. He's using a 'hot stick' here to reach up and lift the blown fusses out, and replace them. There are several different fuse cutouts protecting the line as it runs through the woods, feeding power to the lifts along the back side of the mountain. We usually have three or four instances a season where this happens, usually due to a storm and falling trees. This one was due to heavy, wet snow, blowing two fuses.    Installing the motor at lift 3, back from the shop after a recondition. We got the crane stuck in the mud pretty bad.  |
Craig's blog
The life & times of my electrical world! Archives
March 2016
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