first time ive seen this

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i have for the time fixed the issue by moving all the 120V loads to one leg leaving only the 240V loads tied to the two they are not as picky about the bad leg issue. the house on the other side of the street has all electric heat whenever a 240 V load throws in there is a noticable change in the l-l voltages one leg at both services drops from 121.75V rms to between 114.18 and 113.27V rms. the other leg (B phase or L2) remains steady at 121.52-120.17V rms but if a 120 load throws in on L1 A phase both are all over the place.
so i moved al the 120 loads to the B phase and switched all the pem's to 240V and am simply going to wait for the poco transformer to fault of its own doings as this is a transformer issue not a service drop issue.
 
Ask the neighbor to call as well. If two people are calling from the same transformer, they may be more likely to change it assuming the secondary main has no problems. I would have already had that thing changed for you by now... Your neighbor might be experiencing the same problem, but no sensitive equipment that notice it. You should ask if you can take measurements at their address. Then you will know for sure whether it's the secondaries or the transformer. There could be burned off strands on the secondary wire that nobody can see from the ground. It should be extremely east to narrow down the problem if you can produce it on the spot.
 
i did measure the voltages there and while not admitting anything or how i got them measurements were also taken at the lugs on the can itself one lug is dirt. you need a meter that can read out to 6 decimals to see this mess. (not a cheap meter at all) i carry a $21,600 handheld fluke Spectrum analyzer/DVM/1Ghz dual trace DSO in my toolkit. (belongs the company that i work for) i am not bashing pse's pq engineers, fawn i think thats how her name is spelled, knows her job well. but i am bashing their choice of equipment and their attitude on dealing with checking things out a load box and a 3 1/2 digit dvm are not adequate to diagnose these issues.
 
Well I don't have any more advice from the utility perspective. You would think the time wasted on visits and phone calls is worth more than a 25kva. You're talking thousands of dollars in time as opposed to a $700 dollar educated guess.

I had a similar experience with a 3 phase pad mount where I could not catch anything with a Fluke 37X. Voltage was dipping for a half of a second on one leg. Customer was losing all three phase and most of his single phase was on that phase. Single phase main would trip as well as all 3 phase. It took 6 visits and a recorder to finally see it. They still wanted more data even though I could see the phase dipping. This was a significantly more expensive transformer than a 25kva single phase, but it ended up happening a few more times after they analyzed the first recording and they finally changed it. You can look pretty stupid sometimes to a customer when you keep showing up and bouncing it back to an electrician. I wouldn't even have bothered with the recorder after the second trip for such a small transformer. POCO time is most of the time more expensive than the equipment, especially residential.
 
short of ordering a new can from a dealer and risking baking my egg rolls on a pole the only thing to do is wait for this can to blow and do some damage then they will have to replace the can and pay for all the damaged equipment in both houses.
 
arion said:
short of ordering a new can from a dealer and risking baking my egg rolls on a pole the only thing to do is wait for this can to blow and do some damage then they will have to replace the can and pay for all the damaged equipment in both houses.
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It seems to me that you have a huge problem with your ego. You are so off the wall in your comments I'm amazed that this thread has gone as far as it has. It is obvious that you are so blinded by your own view of yourself that you can't work with others to solve a technical problem.
In reading your OP and various comments that follow, I would not even begin to make any helpful technical comments.
 
Hard to diagnose stuff when ya think ya gotta use 6 decimal places and have the dot one place off , eh.

BTW, what model is that there $21,600 handheld fluke Spectrum analyzer, or is that another decimal (or two) off? I bought my Fluke 123 used for $216.00 or so.
 
the transformer failed internaly and im still a bit deaf it was loud and i was les than 40 feet from it when it blew i had no idea those things could blow like that, i had just been called back to find out why everything was getting low voltage then just as i was heading to the pole to look at the lugs with a spyglass. that thing cut lose and jeez it was like standing next to a bomb. any idea why a transformer which contains inert oils is capable of detonating like a 400 pound bombshell? all the failures ive ever seen were impressive meltdowns where the internals melted into a mass of molten copper. i mean i have heard transformers blow up in storms but not until now been close to one when it blew. it blew itself in half and landed on the ground 10 feet away from the pole. didnt have my camera with me that day otherwise i wouldve had some pics of the huge flaming oil pool around the base of the pole etc.
 
What you experienced was an arc fault. Very similar to an explosive detonation... and in many cases actually more intense. You can find plenty of info on the 'net about 'em... perhaps even glean some youtube videos. I've not witnessed any visually firsthand, but have heard substation and other transformers blow from miles away.


The meltdowns you referred to were resistive faults.
 
the arc from an ac system must be a lot more violent than that of a dc system ..in college and university i was always called the terminator .. my favorite form of entertainment was electrical arcs , and unleashing them across defunct servers to see how much damage they did.. my tool of choice was a 60A 75kv dc voltage multiplier, i would start it up at the operating voltage the server used this was usually 48vdc. then ramp it up till it flashed over i have some pretty incredible photos and videos of this.. various materials when vaporized in an arc create random colors in the discharge. the only parts of those servers ive had explode during this were the large pfc and filter capacitors inside the power entry modules. they are about as loud as a shotgun blast. and oh man they stink bad, and ive also had fun with high amperage bolted faults in the em lab at tokyo u,, but from behind a 240mm thick ballistics panel the blast generated when a 4 sq inch copper bar vaporizes in a flash at 480 volts at 750kamps was kinda quiet compared to this but it did have the effect of making everyone jump back, i wasn't there when they vaporized a copper bar with the system at 50% of its rated amperage, rated system sustained pulse is 600V@12 million amps 5% duty cycle, but i hear it made a massive brownout for about 8 seconds, i did get to see some still pictures of it .. just a black spot with a brilliant white ring around it and a cloud of incandescent copper vapor. riding the shock wave. the spl inside the arc room was 335DB at a temperature of 193K centigrade so i spose thease kind of faults are possible with 10A@7.5kv?
 
In an arc fault, the energy comes entirely from the power source, such as POCO.
It is possible in your case that the failure ended up causing an arc bridging the primary. In the short run the energy available can be far more than on the secondary with some sort of current limiting.
As to whether a DC or AC arc can be more intense and damaging really depends more on the impedance of the source than the type of current.
On the other hand a DC arc is much harder to interrupt, since the current does not periodically go through zero.

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