# ComEd Incoming Voltage Dispute



## mbednarik

call your state utility board. Find out what the allowed variance is.


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## Big John

Most places it's ±5% of nominal measured at the transformer, which means if you're getting 130V at the other end of the service conductors, they're probably even higher at the transformer.

Just curious, though: Why is it worth the fight?

-John


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## nolabama

with monitoring equipment installed if you poco goes out of range +_ 5%seems the going rate .....it then becomes a legal matter - you really want to try to sue ConEd over a couple of volts?? Trust me I feel your pain when it comes to dealing with uncooperative poco's


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## wildleg

2) go to http://www.icc.illinois.gov/ and file a complaint

3) install a buck boost transformer to adjust your voltage (of course, if they lower the voltage at the tranny this will have to change)

1) contact the engineering dept of the utility and ask them if they can lower your voltage at your nearby transformer, explain what has happened , and see if you get some help


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## don_resqcapt19

Illinois permits 127 before the utility has to do anything.


> Allowable voltage variations. For service rendered at the standard service voltage, voltage variations as measured at any customer's point of delivery shall not exceed a maximum of 127 volts nor fall below a minimum of 113 volts for periods longer than two minutes in each instance. For service rendered at voltages other than the standard voltage value, voltage variations as measured at any customer's point of delivery shall not exceed 10% above or below the service voltage for a longer period than two minutes in each instance.


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## guest

Interesting timing on this thread......yesterday I had a power outage of about 5 minute duration. When the power came back on I noticed the voltage was also high...I metered it at 128.7 on one leg and 128.2 on the other. It's still running at that level. 

This was interesting because for the last year or so the voltage was low, I was getting anywhere from 108-116 at the most. 

Methinks the POCO finally fixed a bad line switch or connection somewhere. (Or they replaced a step regulator at the substation...a few years back we had a regular voltage falloff at exactly 8pm every night.)


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## BBQ

This will give you an idea of what the typical limits are.


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## noarcflash

my house is 126volts. never any problems. 15 years at least.

I think 125 is nominal, not 120.


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## Sokitset

I appreciate all of your responses. I'll check into your suggestions. I've also contacted my Village Electrcal Inspector to see if they can help.

In reply to Big John, my primary concern is being able to set up a music studio in this new house. I run all this equipment with conditioned power and my conditioners are unable to function above 127 VAC. They shut down and give me an "unsafe voltage" error when connected.

Secondarily, I'm becoming concerned about laundry appliances, kitchen appliacnes, HVAC system, etc. If everything is getting ~8% more voltage than the nominal rating, what kind of life reduction are the motors in these machines experincing? I don't know the answer, but it sounds expensive.

Again, thanks for the advice.


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## guest

Sokitset said:


> I appreciate all of your responses. I'll check into your suggestions. I've also contacted my Village Electrcal Inspector to see if they can help.
> 
> In reply to Big John, my primary concern is being able to set up a music studio in this new house. * I run all this equipment with conditioned power and my conditioners are unable to function above 127 VAC. They shut down and give me an "unsafe voltage" error when connected.
> *
> Secondarily, I'm becoming concerned about laundry appliances, kitchen appliacnes, HVAC system, etc. If everything is getting ~8% more voltage than the nominal rating, what kind of life reduction are the motors in these machines experincing? I don't know the answer, but it sounds expensive.
> 
> Again, thanks for the advice.


What brand conditioners are you using? I have a Furman PL-plus C that has the meter pegged but has not shut down on overvoltage despite my incoming voltage being at 128 (measured with a true RMS meter.) According to the manual the Furman will shut down at 140+ volts. 

128 vac is is only about 7% over and that should be within tolerance of most gear and appliances. 

If your conditioners are shutting down at 127 volts they are either not working properly or you voltage is actually higher than you think.


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## Big John

mxslick said:


> ...If your conditioners are shutting down at 127 volts they are either not working properly or you voltage is actually higher than you think.


 That's my thinking. Seems to me that one of the whole points of a power conditioner is to handle things like voltage out-of-spec.

-John


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## Wirenuting

If he waits till summer, ComEd will lower the voltage for free. They do it every year without fail.


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## Electric_Light

mxslick said:


> What brand conditioners are you using? I have a Furman PL-plus C that has the meter pegged but has not shut down on overvoltage despite my incoming voltage being at 128 (measured with a true RMS meter.) According to the manual the Furman will shut down at 140+ volts.


Well true RMS doesn't matter for measuring service voltage. If it does matter, then you have way too much THD. 



> 128 vac is is only about 7% over and that should be within tolerance of most gear and appliances.


Except for incandescent lamps. The life is reduced by half for every 5% over rated voltage. 



> If your conditioners are shutting down at 127 volts they are either not working properly or you voltage is actually higher than you think.


Or it's just cheaply made. Cheap UPS' switch to battery and power down. 
Better ones have several taps and relays auto-change the taps.


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## guest

Electric_Light said:


> Well true RMS doesn't matter for measuring service voltage. If it does matter, then you have way too much THD.


I disagree. True RMS does matter, THD or not. Too many non-RMS meters are not accurate enough for what we're talking about here. I have seen errors and differences between meters in excess of 10% even with so-called "good" meters. 




> Except for incandescent lamps. The life is reduced by half for every 5% over rated voltage.


Yep. But since incandescents are on the way out, who cares? :laughing:




> *Or it's just cheaply made.* Cheap UPS' switch to battery and power down.
> Better ones have several taps and relays auto-change the taps.


Bingo. The Furman I have does NOT provide voltage correction, but it still operates within what I consider an acceptable range of voltages. Furman makes a really cool (but kinda pricey) voltage regulator that is one rack space high, and uses a toroidal autotransformer with multiple taps to keep the voltage within a few % of 120 (or 240). It uses triacs to switch between taps and IIRC it does it on Zero crossing. 

While working with an A/V company we had one that suffered a meltdown.....Furman replaced it for free and discovered a slight flaw in it's operating controller that allowed two triacs to turn on at the same time.... they fixed that and added protection against shorted triacs.


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## Electric_Light

mxslick said:


> I disagree. True RMS does matter, THD or not. Too many non-RMS meters are not accurate enough for what we're talking about here. I have seen errors and differences between meters in excess of 10% even with so-called "good" meters.


Then you have excessive harmonics. Average sensing meters are designed to provide proper RMS value on a clean sinusoidal wave which the utility service should be. 


What kind of power were you dealing with? gennie, inverter, somewhere that use a lot of computers (which can cause flat topping on waveform)?


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