Some Diverse Interests


Home → Too much voltage


Complaint about Too Much Voltage from Hydro One

Is Your Electricity Bill Too High?

If your electricity bill is too high, one of the reasons might be that your electricity company is delivering too much voltage to your house.  Your appliances don't need that extra voltage but you have to pay for it anyway.  My electricity company is Hydro One which delivers electricity directly to most rural and some suburban customers in Ontario, Canada. 

In North America, your electrical appliances only need 120 VAC (volts alternating current), plus or minus a few volts for variations in load.  If your electricitly company, like Hydro One, delivers voltages that are consistently higher than 120 VAC then your appliances will consistently use more power than they need and you have to pay for more energy than you needed. 

Higher Voltage  =  High Electricity Bills !

Too much electricity equals too much voltage, which causes too much current to be drawn, which causes too much power to be dissipated, which over time will cause too much energy to be consumed. 

Current Situation at My Home  (15 July 2017)  —
While we did not see the extraordinarily high voltages during Winter 2016/17 that we observed during Winter 2015/16, the average voltage is still higher than it needs to be.  So far during this summer the voltage has averaged around 122 VAC.  This adds about 3% to the electrical portion of my bill each month.  Hey, Hydro One!  What's going on?

How to Tell If You Have Too Much Voltage in Your House

Digital voltmeter used to test voltage at wall outlet

If you have a digital multimeter or other suitable instrument that can measure the appropriate voltage range, check the voltage that appears at the electrical outlets on your walls.  It should be within a very few volts of 120 VAC.  This is an acceptable voltage.  Check it at different times of the day and night for several days to find a reasonable average.  If you find that the voltage at your wall outlets is consistently around 124 VAC or higher, then you have too much electricity in your house and you are using and paying for significantly more energy than your appliances need. 

Please Note —  You are dealing with a potentially lethal voltage, so if you cannot check the voltage safely by yourself, please have a qualified electrician, technician, technologist, or engineer do it for you.  There is no shame in this and it might save your life. 

How Much Is Too Much Voltage?

The voltage at your wall outlets should be within a few volts of 120 VAC, say 118-122, because all the domestic appliances that are approved for sale in Canada by the Canadian Standards Association (CSA) are rated to work at that voltage (except, of course, the ones rated for 240 VAC). 

Chart of CSA standard 
voltage ranges

The yellow zone is the range of voltages measured at my residence during December 2015 and January and February 2016.  (Winter 2015/2016 was not the first winter when I have experienced such high voltages but I hope it will have been the last.) 

The green and red zones are as defined by the Canadian Standards Association document CAN3-235-83 Table 3, "Recommended Voltage Variation Limits for Circuits up to 1000 volts at the Service Entrance".  (See especially the "Voltage Guidelines" on pages 35-36 of the Ontario Energy Board document.)  The Ontario Energy Board states clearly that

Hydro One will supply standard voltages only.  These voltages will conform to Canadian Standards Association (“CSA”) standards.

In fact, these same standards are repeated in Hydro One's statement about conditions of service to Hydro One customers.  (See especially page 49.)  So we know that this standard is used by Hydro One and that the voltage should always be in the green zone and should never be in either of the red zones. 

The CSA recommendation for normal operating conditions is 110-125 VAC, but as any electrician will tell you it can be dangerous to operate for long periods of time at the upper end of that range.  In fact, the same CSA recommendation defines 127 VAC as an "extreme operating condition"

My Complaint

During the winter of 2015/16 the voltage at my house averaged between 124 and 125 VAC and was higher than the green zone about half of the time, occasionally verging on the upper red zone.  No wonder my light bulbs burned out that winter, even the expensive CFL lamps, and the high voltage might explain why our expensive HD TV receiver froze up for hours at a time in spite of receiving strong TV signals.  While these high voltages have not appeared since then, Hydro One could change their minds at any time and again deliver these almost extreme voltages.  See here for a summary of the voltages being delivered to my house by Hydro One over the months beginning with December 2015. 

What Is Happening

Scientists are seldom heard from, lawyers almost always ... Moreover, if the ... story depends in any crucial way on something technical, one can be sure that it will be too boring to make compelling reading or viewing.
- John Allen Paulos, "A Mathematician Reads the Newspaper" (1995), p 84.

You might remember from your high school physics class that, at 120 volts, a 100 watt incandescent light bulb dissipates 100 watts of power in the form of light and heat.  That is normal and that is what we expect to pay for when we turn on the light switch. 

How Voltage Affects the Power Used
If Your
Voltage Is
Power Used By
A 100 W Load
And You Pay
This Much More
118 VAC 96.6 W -3.3%
120 VAC
100 W 0%
122 VAC 103.4 W +3.4%
124 VAC 106.8 W +6.8%
 126 VAC  110.3 W  +10.3% 
 128 VAC  113.8 W  +13.8% 
 130 VAC  117.4 W  +17.4% 

However, with 124 VAC that same light bulb will dissipate almost 107 watts and you will pay almost 7% more for your electricity.  At 126 VAC, the bulb will dissipate just over 110 watts and you will pay 10.2% more for your electricity.  Your refrigerator, freezer, furnace, TV set, light bulbs, sump pump, well pump, washing machine, clothes dryer, cell phone chargers, computer, home theater, coffee maker, all of your appliances will be similarly affected by the higher voltage that is delivered by Hydro One.  And you will pay for that extra energy.  All the time. 

Note to Readers — You win extra points if you have noticed that power and voltage do not have a 'linear relationship'.  The power (and the energy) are proportional to the square of the voltage, so as the voltage is increased, the power and the energy will increase quite a bit faster than the voltage.  The exact relationship is very accurately described by Ohm's Law.  Ask any engineer. 

It's a Bit Like ...

  • having to buy gasoline at a pump that deliberately overfills your tank and you have to pay for all the gas that spilled on the ground even though you can't use it.
  • having to pay for an extra seat (empty!) every time you take your family to the movie theatre.

Why Does Hydro One Do This?

To make more money, of course.  Hydro One normally has a surplus of energy to sell, especially during the winter, and they deliver the higher voltages to our homes in order to sell that extra energy to us. 

Once a basic amount of energy has been produced and sold, any extra energy is much cheaper to produce, so profits are high when Hydro One can sell their surplus energy.  As customers, you and I are the buyers of that surplus. 

It is strange that, on one hand, Hydro One is always emphasizing the importance of saving energy by using programmable thermostats, compact fluorescent lights (CFLs), EnergyStar appliances, and paying attention to the Time of Use schedule, while, on the other hand, delivering a level of voltage that cancels out any saving from these conservation efforts. 

Excuses! Excuses!

In years past when I have complained to Ontario Hydro, now Hydro One, about the high voltage at my home, they have given several different "reasons" but none of these reasons is really valid. 

  • "But we would have to reduce your neighbours' voltage, too."  —  Doh!  Of course you would.  All of my neighbours' voltages are too high, just like mine, and so should be reduced. 
  • "We like to deliver a higher voltage so that motors will start easier."  —  Excuse me, but I live in a residential neighbourhood, NOT an industrial park, and I can count on one hand the number of significant motors in my home.  All of them are rated at 120 VAC and they work just fine at that voltage. 
  • "But the voltage varies and it isn't high all the time."  —  Yes, the voltage varies alright, and it is the times when it is too high that I am complaining about.  During December 2015, I measured the voltage 135 different times, more or less at random during the days and nights (I'm a bit of an insomniac), and the voltage was never less than 121.0 VAC (already higher than the nominal 120 volts) and as high as 127.2 VAC.  The average of my measurements over the month was 124.25 VAC so my neighbours and I were using about 8% more energy than necessary.  And, Yes, the voltage was still too high most of the time during the rest of the winter.  (See the charts of my measurements for more details.)
  • "But you have it all wrong!  The current decreases as the voltage increases, so the power stays the same."  — This line, this totally untrue statement, was tried on me by a professional working in the power industry.  It is a complete misstatement of Ohm's Law, as can be verified by reference to any physics or electrical engineering textbook.  It is an outright lie and a neat piece of propaganda used to divert factual criticism of the power industry, and while it might work on uninformed journalists, politicians and senior bureaucrats, it didn't work on me. 

All of this from Hydro One and the power industry, who like to paint themselves as guardians of conservation and energy efficiency.

The Bottom Line

Ideally, the average voltage over a 24-hour period should be 120.0 VAC and vary between, say, 117 and 123 volts, or better between 118 and 122 volts, depending on supply and load conditions.  So, the voltage should be above 120 volts about half the time and below 120 volts the other half of the time.  Hydro One should strive to achieve that level of supply for all residential neighbourhoods.  That is fair and proper and does not cause our appliances to use more power and energy than they are supposed to or cost us more money than we should pay.  With smart meters and other telemetry systems, Hydro One knows exactly how much voltage they are supplying and have no excuse for not being aware of the excess and costly voltages that I have described above. 

The results of many measurements at my own home are summarized here.  It was necessary to take a large number of measurements each month in order to assure accuracy and to overcome the effects of hour-to-hour and day-to-day variations in load and in capacity of supply.