Increased energy useage

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nizak

Senior Member
I have a customer who occupies a small commercial suite. There are 4 or 5 computers, a printer, and a dozen or so 2'x4' fluorescent lay in's along with general purpose receps throughout.On the two occasions I checked the panel load there was never an amp draw over 30 except when the copier kicked on, it would bump up an additional 12-13 amps.There is a microwave that is seldom used.

The last two months their electric consumption has increased approx. 70%. They have added no additional equipment to the suite. The utility assures them that the meter is functioning properly and that it is an issue on their end.
Is there anything that would stand out to you's here that would cause that type of increase? The A/C is metered through a house panel that is paid for by the building owner. I looked at past billing and found monthly usage to be consistent at about 390-400 KW/hrs. The last two months have shown readings of 650 and 667. I looked at the meter and they are right on track for another reading in this range.The only high wattage draw seems to be the copier, could it possibly be a heating element of some kind in it that intermittingly does not shut off?
Any thoughts appreciated.
 

nizak

Senior Member
The meter bank is comprised of 4 Tennant and 1 house meter. It's straight forward as to what panels are being fed, you can physically see the conduits from point A to B. Meter # corresponds with # on billing invoice. I don't see how wrong meter read could have occurred.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
141002-0759 EDT

nizak:

A change from 400 kWh to 650 kWh is significant. Or about 8 kWh per day. The 400 kWh is about 13 kWh per day.

30 A at 120 V is about 3.6 kW. For 8 hours this is 28.8 kWh. No way is their continuous daytime load 3.6 kWh. An 0.5 power factor would bring this down to 15 kWh per day.

Was the meter changed between the two time frames, the lower usage and the higher usage?

Was there a smart meter in use during both of the time frames?

If a smart meter was present during both time frames, then can you get hourly data from the power company for those time frames? See two pages from my web site:
http://beta-a2.com/energy_c.html only hourly data from smart meter.
http://beta-a2.com/energy.html both 1 second and hourly data from TED system.
The graphs will provide you with some idea of the type of information you can get from hourly data.

Ask questions about what equipment changes or usage may have occurred.

A small laser printer will only have the heater on while printing. Thus, its average standby power is likely in the range of 5 W, and 11 VA. While printing about 450 W initially down to about 300 W at the end of one page. VA from around 450 down to 350 to 390.

A larger laser printer has a keep-warm pulsing technique. Base continuous power of about 35 W and 75 VA. The keep-warm pulse power is about 500 W with a duty cycle of about 20% or an average power of 100 W plus the 35 W. Power while printing might be in the range of 500 to 1000 W. Your laser printing current would imply a moderate size printer.

A TED type system might be useful in studying power usage (2 to 5 second time resolution), but won't be as power or energy accurate as a correctly working power company meter.

.
 

kwired

Electron manager
Location
NE Nebraska
The meter bank is comprised of 4 Tennant and 1 house meter. It's straight forward as to what panels are being fed, you can physically see the conduits from point A to B. Meter # corresponds with # on billing invoice. I don't see how wrong meter read could have occurred.
Wrong meter read is still possible, does reading on the bill correspond with current reading on the meter, all the reader had to do is write the reading down in the wrong space on his reading form. I think the question of loads in other tenant spaces was more about a branch circuit possibly being connected to the wrong panel somehow. Could have been that way a long time but was never seeing the kind of load is has seen recently for some reason.

Otherwise the usual culprits always mentioned in these kind of cases is water heaters - including non electrical issues such as a leaking hot water faucet, refrigerators, heating/air conditioning - though you said AC is on a different meter.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Tell them to turn off the grow lights---
Or look for an illegal tap off one of their circuits going to somebody else's grow lights.
Use a clamp meter on all of the branch circuits.
Check whether the copier is not going into power save mode at night for some reason (it is usually a config option).
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
It could be the copier, yes, depending on what type it is. People often buy old copiers, or get them for free, not thinking about why the previous owners were so willing to let them go; the old ones were energy hogs if they had a drum that needed to be kept warm. Someone may have inadvertently (or purposely) changed a setting as well so that they don't have to wait for the copier to warm up for them in the morning, which means it is now running 24/7. That can add up.

You can get a little plug-in device called a "Kill A Watt" for under $50 that will record the kWh of anything plugged into it. It's not as wide reaching as the TED described above, but it can be used to confirm or deny a theory on a specific plug-in load.
 

kwired

Electron manager
Location
NE Nebraska
It could be the copier, yes, depending on what type it is. People often buy old copiers, or get them for free, not thinking about why the previous owners were so willing to let them go; the old ones were energy hogs if they had a drum that needed to be kept warm. Someone may have inadvertently (or purposely) changed a setting as well so that they don't have to wait for the copier to warm up for them in the morning, which means it is now running 24/7. That can add up.

You can get a little plug-in device called a "Kill A Watt" for under $50 that will record the kWh of anything plugged into it. It's not as wide reaching as the TED described above, but it can be used to confirm or deny a theory on a specific plug-in load.
With TED you would need to clamp the current CT's directly to the circuit to be monitored if you want to monitor a specific circuit. They can be trained to recognize a particular load but if you have other individual load of similar characteristics it may not know the difference
 

growler

Senior Member
Location
Atlanta,GA
I have a customer who occupies a small commercial suite. There are 4 or 5 computers, a printer, and a dozen or so 2'x4' fluorescent lay in's along with general purpose receps throughout.On the two occasions I checked the panel load there was never an amp draw over 30 except when the copier kicked on, it would bump up an additional 12-13 amps.There is a microwave that is seldom used.
The only high wattage draw seems to be the copier, could it possibly be a heating element of some kind in it that intermittingly does not shut off?
Any thoughts appreciated.

It could be the copier but it could be other things.

I'm with Kwired on this and would also check the water heater. Most people don't understand how much it cost to heat water.
 

kwired

Electron manager
Location
NE Nebraska
Not an expert on copiers/laser printers, but am certain the heater only cycles to maintain a specific temperature. If not actively printing it should cycle to maintain temp, if it fails to cycle and stays continuously on - something will overheat and effect performance of the printer.

Now I suppose it is possible the thing is maybe remaining in a standby mode instead of going to sleep mode when it is not in use - that could use a significant amount of energy. Most only remain in standby for a few minutes of inactivity before going to a sleep mode.
 

foo

Member
Location
United States
You could use the kill-a-watt on each device. Let it capture an amount of hours worth of usage and use that data to average usage for whatever amount of time they use each device each day/week/month. There may be some ratings(wattage) on most of those devices that can save you some time and allow for some instant calculations.

You could also place an ampmeter on each circuit at the breaker and see what each circuits power draw is. As long as the panel is labeled it should be easy to track down the usage. Might even find a troubled circuit with higher draw than you'd expect.

Is someone using a floor heater under their desk? Maybe left one plugged in? Is someone plugging in a new device(s) at their desk for recharging purposes? I've seen co-workers take in rechargables into work to take advantage of the electric there.
Any device with a coil/element is suspect as bad coils/elements draw more amperage to overcome the breakdown.

I remember a neighbor girl who lived in a small trailer that had an electric meter that was spinning like it was an industrial grade service. The electrician that came to check things out found a circuit had been bleeding to ground.
Another neighbor found that he had forgotten to unplug the heat tape for his pipes all summer long. Wasted power.

Please post back with your attempts/findings.
 

meternerd

Senior Member
Location
Athol, ID
Occupation
retired water & electric utility electrician, meter/relay tech
Ask the POCO if they'd be willing to install a recorder on the service for a few days to record usage patterns. We are a small utility, but have two recorders used for just the situation you have. It's always convenient to blame the meter, but in my experience, meters never run fast. Could be a misread, but not for two or three consecutive months. Probably you'll just have to put an amp clamp on each breaker and watch to see which circuit is the culprit. You can watch the meter to see when it speeds up. Disk rotation on mechanical or pulse rate on solid state.
 

foo

Member
Location
United States
Ask the POCO if they'd be willing to install a recorder on the service for a few days to record usage patterns. We are a small utility, but have two recorders used for just the situation you have. It's always convenient to blame the meter, but in my experience, meters never run fast. Could be a misread, but not for two or three consecutive months. Probably you'll just have to put an amp clamp on each breaker and watch to see which circuit is the culprit. You can watch the meter to see when it speeds up. Disk rotation on mechanical or pulse rate on solid state.

Have you found any of the new solid state meters to be outside tolerances during your testings?
 

meternerd

Senior Member
Location
Athol, ID
Occupation
retired water & electric utility electrician, meter/relay tech
Have you found any of the new solid state meters to be outside tolerances during your testings?

Sorry for the late reply...been gone.

No...all new SS meters I test are 100.02 % or better. We get the factory test results, but still test 10% of the new meters ourselves using a tester calibrated and certified to NBS standards. I have found meters that are non-functional but have never found any with errors. Older mechanicals sometimes tested slightly slow (never fast) but very rarely. Usually they just die completely due to burned out voltage coils.
 
Sorry for the late reply...been gone.

No...all new SS meters I test are 100.02 % or better. We get the factory test results, but still test 10% of the new meters ourselves using a tester calibrated and certified to NBS standards. I have found meters that are non-functional but have never found any with errors. Older mechanicals sometimes tested slightly slow (never fast) but very rarely. Usually they just die completely due to burned out voltage coils.
At my personal house we took a lightning strike that knocked out my dishwasher, microwave and numerous other circuit boards. From that point on my meter read about 30% high. It was a mechanical meter. Poco came out and did not want to believe it but after some persuasion agreed to test meter and found it reading high. They credited me $900 for 3 months of high readings.
 

foo

Member
Location
United States
Sorry for the late reply...been gone.

No...all new SS meters I test are 100.02 % or better. We get the factory test results, but still test 10% of the new meters ourselves using a tester calibrated and certified to NBS standards. I have found meters that are non-functional but have never found any with errors. Older mechanicals sometimes tested slightly slow (never fast) but very rarely. Usually they just die completely due to burned out voltage coils.


Those that were non-functional; was it because the board connector came loose? Possibly from movement in transit?
 

foo

Member
Location
United States
At my personal house we took a lightning strike that knocked out my dishwasher, microwave and numerous other circuit boards. From that point on my meter read about 30% high. It was a mechanical meter. Poco came out and did not want to believe it but after some persuasion agreed to test meter and found it reading high. They credited me $900 for 3 months of high readings.

Must have affected the magnetic brake. Those old meters had to be designed so that a rise in temperature wouldn't cause them to speed up.I imagine a lightning strike was much more heat than their design could handle. I don't blame 'em. It's not a gazillion degrees outside every day. hehe
 
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