why i am still getting 110 volts (line to neutral) during brownout

Thread Starter

akane matcha

Joined May 11, 2020
4
A hopeful and blessed day to all,

New here, good day.I searched the internet but cannot find the answer. There was a brownout in our entire block. our power configuration as follows - only two wires going inside the residence panel box, L1 to ground is 110 volts, L2 to ground is 110 volts. Our supply here is L1-L2 is 220 volts. So it was a long brownout and checked my L1-L2 at 0 volts (as expected). However my L1 to gnd as well as L2 to gnd remain at 110 volts. Out of curiosity , which I know is not supposed to be done, I plugged in to the 110 volt line to ground a small cellphone charger (5 volts 2 amps) and the voltage falls to 95 volts.

My curious question is why even at brownout I still read 110 volts from line to ground although the current is very low? what can possibly happen that a brownout occured and the line to ground redings are low current 110 volts?

Thanks in advance.
 

Janis59

Joined Aug 21, 2017
1,183
Wow, that was our Riga network one and half centuries ago. Last substations was re-wired so late as1980, so I remember this wonder what means the both wires "fiery". and what means to take electricity in by nul-wire against ground wire in the manner for kWh counter not turns. Probably that was a major concern why they changed to 220/380 instead of historical 127/220. But for us that never was a low current.

But about to that fast falling voltage I have a story from 70~ies and my father countryside house, where the country power-lines all was thin but long thus the inner resistance was everywhere the hard problem. Then he bought a water pump having 2 kW motor. So the voltage fell from 220 to 120 and motor only buzzed without of any turning. So I "borrowed" my workplace the 3 kW ferroresonance stabilizer what have no owner wooing after it, and just got a near dead as heavy it was, of course the personal car was something un-immagineable then costing a hundred whole-life salary price for one, so somehow we managed to carry on hands that 200 kg brick a 12 kilometers off road and when I switched it to netwok, the output voltage fell even lower to 85V but the power grid voltage to lucky 11 volt. Then it stopped by substation fuse. So, the well lesson was, You never cannot pump out more than it holds inside.
 
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Thread Starter

akane matcha

Joined May 11, 2020
4
I was wondering if the power provider transformer's neutral line grounding was so far from us, does it affect the low current drawn? Even then the question is why i have 110 volts line to ground for each line but 0 volts for line to line voltage for this particular brownout? thanks
 

Tonyr1084

Joined Sep 24, 2015
4,554
Welcome to AAC.

What you describe shouldn't happen. Not saying it didn't. Just wondering if maybe someone had a generator running and not properly connected. They may have been back feeding power to the grid. It's a weird situation to say the least. But perhaps you're confusing voltage with power.

Voltage is best described as "Electric Pressure". Current is the flow of electricity. You can have a tiny wire carry a very high voltage but nearly no current because it's too small to conduct a lot of current. You can also have a very low voltage that can deliver very high amperage, but you'd need a much heavier cable because of the current. "Power" is the multiple of Voltage and Current. If you have 110 volts and 50 amps of current the power is 110 x 50, which equals 5500 watts.

I moved my refrigerator. Turned off the circuit, then used a NCVD (Non-Contact Voltage Detector) to verify the circuit was dead. The NCVD indicated there was still power there, so I plugged a vacuum cleaner into that outlet. The vacuum did not run, but still tested as having 110 volts on the line. Not sure exactly why - I shut the whole house power off before moving the plug. And I still can't explain why my tests were what they were.

Your brown-out may have been a reduction of power. Remember, power is volts times amps. The voltage may still be there, but the current (amps) may not.
 

Tonyr1084

Joined Sep 24, 2015
4,554
May be wrong but I always thought that was the definition of a brown out. Voltage without the amps.
Thought that was what I was saying - voltage without the amperage. Hence a browning out of power. Line resistance could account for a loss of amperage. I would imagine it can be from a number of other causes as well. It's like when you have a 12 volt transformer that is rated at 1 amp and you try to draw two amps - the voltage drops to 6 volts.

I don't know this for a fact - but if transmission lines are compromised, doesn't that reduce the amount of power reaching a community? Hence - a brown-out. If a line goes down (or is shut down due to heavy demand) that makes less power available at the end user. So if 200 homes are drawing 100 amps each, that's 2.4 MW (Mega Watts). If the power company or power lines can't carry that much power - then something is going to go brown. Now, a BLACK-out - that's a total loss of power due to whatever reason; a sub station blowing up, a generating plant losing its ability to produce electricity - whatever.

@MaxHeadRoom defined 10% reduction in voltage as a brown-out. I can't argue with that. In fact, that's a lot of voltage lost. And as discussed, a brown-out is when power drops off. Not out - off.
 
Because the DMMs are such a high impedance, they may detect leakage currents....currents to small to actually produce any power, but with the high DMM impedance they will still register.

That is the reason many DMMs geared towards the electrician's market have a LoZ voltage function. For instance, the Fluke 117 description mentions: "...features a LoZ function to help get the job done faster and prevent false readings caused by ghost voltage."

Something similar happened to me many years ago, before DMMs were widely available: There was a brownout, and the home's lights would of course not turn on, but small neon "night lights" would still glow. This was my first introduction to leakage currents.
 

BobaMosfet

Joined Jul 1, 2009
1,111
A hopeful and blessed day to all,

New here, good day.I searched the internet but cannot find the answer. There was a brownout in our entire block. our power configuration as follows - only two wires going inside the residence panel box, L1 to ground is 110 volts, L2 to ground is 110 volts. Our supply here is L1-L2 is 220 volts. So it was a long brownout and checked my L1-L2 at 0 volts (as expected). However my L1 to gnd as well as L2 to gnd remain at 110 volts. Out of curiosity , which I know is not supposed to be done, I plugged in to the 110 volt line to ground a small cellphone charger (5 volts 2 amps) and the voltage falls to 95 volts.

My curious question is why even at brownout I still read 110 volts from line to ground although the current is very low? what can possibly happen that a brownout occured and the line to ground redings are low current 110 volts?

Thanks in advance.
You should understand the difference between a brown-out and a black-out. A brown out is not a loss of voltage & current. A brown out is a regulated condition by the utility whereby they will drop voltage, current, or both as necessary to provide some power, but it may or may not be ideal. Many VAC devices will operate for a period without damage in such conditions, but only for short periods, while other will not function correctly. Your utility attempts to provide a service, but at the end of the day, it protects its network over your need for power.

A black-out is a loss of power (voltage and current).

The voltage you see unloaded is ideal because very little current is drawn. A load uses current. If more current is being drawn by the load, than the vendor can supply at a given voltage, voltage will drop to compensate. This is Ohm's Law in action. Voltage and current DO NOT ever act independently of one another unless designed to do so by some intervening mechanism/circuit.
 

BobaMosfet

Joined Jul 1, 2009
1,111
Here is the simple diagram. not sure of the accuracy of the transformer at the power pole.
The job of the transformer at the pole is to drop the local 7.6kV feeder to 220V for your house, split across both sides of your outside breaker panel. It has nothing to do with generation. Generation is handled by a generating station, and switched by a substation at the head of the feeder that feeds your neighborhood. Back in the day, they tied the ends of the feeders together to help reliability and improve distribution to homes, but it was later deemed expensive, and unnecessary (your need for power isn't critical in their world).
 

Thread Starter

akane matcha

Joined May 11, 2020
4
sorry i used the wrong term. instead of brownout it should be power outage. but here in our part of the world a localized power outage is reported as brownout. sorry.
but unfortunately i still don't have the answer to satisfy my curiosity with this. maybe my explaining is not clear enough.
 

#12

Joined Nov 30, 2010
18,210
Because the DMMs are such a high impedance, they may detect leakage currents....currents to small to actually produce any power, but with the high DMM impedance they will still register.
That idea is why I'm here. When the load is very nearly zero, any small leakage can put power line voltage on an outlet. Even capacitance can do that. It's called ghost voltage because it will disappear the instant you try to put a load on it. A 10 meg multimeter only allows 12 microamps to flow from a 120 volt line. The leakage resistance can be most of a megohm and your high tech meter will convince you there is power availabe, but it isn't.
 

vu2nan

Joined Sep 11, 2014
148
A hopeful and blessed day to all,

New here, good day.I searched the internet but cannot find the answer. There was a brownout in our entire block. our power configuration as follows - only two wires going inside the residence panel box, L1 to ground is 110 volts, L2 to ground is 110 volts. Our supply here is L1-L2 is 220 volts. So it was a long brownout and checked my L1-L2 at 0 volts (as expected). However my L1 to gnd as well as L2 to gnd remain at 110 volts. Out of curiosity , which I know is not supposed to be done, I plugged in to the 110 volt line to ground a small cellphone charger (5 volts 2 amps) and the voltage falls to 95 volts.

My curious question is why even at brownout I still read 110 volts from line to ground although the current is very low? what can possibly happen that a brownout occured and the line to ground redings are low current 110 volts?

Thanks in advance.
Here's a scenario.

untitled5.JPG

Voltage readings, after a wire break, are shown.

- Nandu.
 
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