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Old 09-16-2011, 12:37 PM   #16
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Voltage drop? Lights dim with load on different circuit.


"Resting" voltage tested between the right leg (red stripe) to the neutral is a stable 118.0V
Sump pump kicks on - voltage drops slightly to about 117.6V but does not seem to fluctuate
Sump pump finishes pumping water and runs "dry" for about 2 seconds before shutting off - no change - 117.6V
Sump pump shuts off - voltage slowly creeps back up to 118V

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Old 09-16-2011, 01:41 PM   #17
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Voltage drop? Lights dim with load on different circuit.


Try this too:
With minimum load operating, measure from the left hot to the right hot.
Then turn on as much stuff as you can, lights, AC, dryer if electric, and any other appliances.
Read from left hot to right hot both above the main breaker and below the main breaker.
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Old 09-16-2011, 07:56 PM   #18
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Voltage drop? Lights dim with load on different circuit.


Alright here are my readings for a7ecorsair's request:

Minimum load (pretty much the only thing still running is refrigerator, minifridge and fishtank): 233.5V

Then I turned on every single thing in the house except for the central air because it has already been prepped for winter and covered. This includes: every single light and floor lamp (approx 24), range hood, 2 box fans, bathroom vent, 1875W hair dryer, toaster, microwave, gas clothes dryer, washing machine on spin cycle, furnace blower, HDTV, 2 game consoles, 2 MacBooks charging, outdoor flood light, and a 1500W work lamp. The above mentioned fridges and fishtank remained on. I also started the sump pump.

Reading with all of that load on and sump pump running: 223.7

A difference of 9.8V across the two legs.

What does that tell you?
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Old 09-16-2011, 08:13 PM   #19
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Voltage drop? Lights dim with load on different circuit.


transformer sounds too small if the voltages between legs and neutral stay consistent
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Old 09-16-2011, 08:32 PM   #20
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Voltage drop? Lights dim with load on different circuit.


The change in mains voltage of 10v is not too bad,
But it does point to the problem being a poco problem.
There simply is not enough power available from
the local grid.
You should contact a good electricain and get him to verify your findings, then contact poco and request an upgrade in available power.
They might have to upgrade the local transformer.
But they wont do it unless someone requests it first.
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Old 09-16-2011, 09:19 PM   #21
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Voltage drop? Lights dim with load on different circuit.


The 233 volt reading is good so the drop you see is all yours. Do you have a pole mounted transformer? If so, how many services are being fed from it?
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Old 09-16-2011, 09:25 PM   #22
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Voltage drop? Lights dim with load on different circuit.


Yes, it's a pole-mounted transformer, right across the road from the house. I will have to check how many other homes this transformer services tomorrow in the daylight. There is also a small commercial building next door (warehouse) though I'm not sure if it is connected to "our" transformer or not. It is close enough in proximity to our house that it just might be.
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Old 09-16-2011, 09:55 PM   #23
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Voltage drop? Lights dim with load on different circuit.


A significant voltage change due to one appliance (even a heavy draw item) in your house is something not upstream of the pole transformer. No one appliance in your house can affect the entire grid that much.

117.6 volts, sump pump turns off, voltage slowly creeps back to 118.0 volts.
I think that this difference is too small to have any meaning.

Is the differential (more correctly difference) in voltage (233.5 vs. 223.7 or 9.8 volts in your case) the same if you did the same test but measured between the breaker screws of two branch circuits' breakers one on each side of the line? We want to see if any additional voltage drop is happening within the main breaker or the bus bars under it which could mean a deteriorating connection in the panel.
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Last edited by AllanJ; 09-16-2011 at 10:03 PM.
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Old 09-16-2011, 10:07 PM   #24
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Voltage drop? Lights dim with load on different circuit.


The only reason I placed so much focus on that sump pump is because that seems to be the appliance which causes my UPS to flip out most of the time. If I remember correctly, the central air would do it too.

The crazy thing is, today when I was doing all of this testing, even with all those loads on, I didn't hear one peep from my UPS. The lights still dimmed and the most noticeably affected things were the range hood and the sump pump, which both operated more slowly/quietly with the heavy load on the house's electrical system.

I'm still totally confused. I understand that my little sump pump will not affect the grid all that significantly - and I also know that I need to go ask the neighbours on the same transformer as me if they experience similar dimming of lights and slowing of fans when a load is applied. I can tell that the slightly smaller house to the North has central air and a gas furnace, so they may be a good comparison to mine.
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Old 09-16-2011, 10:41 PM   #25
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Voltage drop? Lights dim with load on different circuit.


Dont forget you also have to consider,
What else is running off that one transformer at the same time.
If the mains has dropped off, and is sitting close to the switch over
point for the ups, then almost anything could be enough to
trip it over.

I would set up my volt meter,and monitor the mains variations,
use a pen and paper and log them, say every 30 mins.
You will then see if there is any pattern to it.

But remember what is happening at other houses
that are on the same tranny, could play a part in the problem,
especially if it is a poco problem.

But once you can see a pattern to the problem
then solving it will be that much easier.
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Old 09-18-2011, 09:35 PM   #26
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Voltage drop? Lights dim with load on different circuit.


Quote:
Originally Posted by AllanJ View Post
Is the differential (more correctly difference) in voltage (233.5 vs. 223.7 or 9.8 volts in your case) the same if you did the same test but measured between the breaker screws of two branch circuits' breakers one on each side of the line? We want to see if any additional voltage drop is happening within the main breaker or the bus bars under it which could mean a deteriorating connection in the panel.
Sorry, AllanJ, I did not notice this part of your post.

Tomorrow, I will perform the same test as before and measure on each individual leg.


dmxtothemax, I was not home very much this weekend to monitor/log the mains voltage but I will try to get this done at some point.
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Old 08-01-2012, 10:03 PM   #27
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Voltage drop? Lights dim with load on different circuit.


So I know it's been a long time since I've posted here, but I've honestly had more pressing things to deal with the last few months. I've made progress and didn't want to leave you hanging any longer.

I finally called the utility about this today. The linesman who came out made a startling discovery!

He stood in my yard and was like "where's the transformer for your house?" - of course I had no idea, so he was looking up and down the block until he found one WAY off in the distance. He called his dispatcher to confirm, and sure enough that was our transformer. Here's the kicker:

It's a 20 kilovolt transformer (which, according to the linesman, is supposed to serve 6 or 7 households).

It is currently serving TWENTY FOUR households! Haha! Basically my entire street is on the same undersized transformer, and we are close to the "end of the line". Got to love the infrastructure out here in rural PA.

The linesman called it in, and my work order was escalated in order to get a larger transformer (or multiple smaller ones) installed to upgrade our street.
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Old 08-02-2012, 05:06 AM   #28
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Voltage drop? Lights dim with load on different circuit.


Thanks for the update !
Yes the tranny is too small for 24 houses !
And its a 20Kw tranny not a 20Kv tranny.
Sorry to nit pick !
I am surprised the tranny has lasted with such a load.
Maybe this is why tranny explosions are so spectactular!
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Old 08-14-2012, 11:18 AM   #29
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Voltage drop? Lights dim with load on different circuit.


Well I keep calling the POCO back several times a week to see when they plan to replace the transformer, but I keep getting the "it's in our system, we'll get to it" response. I'm gonna keep bugging them until they finally fix it.

My first thought was to fire up up a bunch of space heaters, air conditioners, refrigerators, and a welder at my house - and have my next door neighbour do the same - to see what kind of problems we can cause. I have a 200A service and the neighbour has 100A - our maxed out services plus the additional loads of the rest of the houses on the block should get the POCO's attention!

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