Unexplained power usage?

[Fifty]

My shop is in a commercial building and I have a dedicated 3 phase 208v service. (125 amp) I was looking at the day by day power breakdown from my fancy smart meter, and something isn't adding up. Looking at days where I'm not at the shop, I'm using more than 4 kilowatts.

I don't have much plugged in, and I've been checking the things I leave on with my kill-a-watt meter.
Computer - 1.58kwh/day
Fish tank - .26kwh/day
Fridge - 1.62kwh/day
That's only 3.46kwh/day. Still missing more than .5kwh! As best I can tell nothing else is on or even plugged in after I leave. My fridge is old, but my kill-a-watt says it only uses 1.62kwh/day, and that was a hot day.

Where is that extra 500 watts going? I'm starting to wonder if some of my wires aren't powering something in the neighbor's shop. (same building) Should I complain to the power company?

This is the hour by hour graph from the power company. Are those peaks my fridge kicking on and off? This is from a day where nobody was at the shop. I'm not sure what that big peak around 2AM could be? There are no lights on when I am not there, besides the fish tank. (20 watts)

 

[HOTFR8]

Sounds like time to call an electrician and see if a wire goes to something you do not know about. Do you have any security lights ? If you have power going to next door why ? An Electrician will trace the wires and shut that off for you.

 

[Fifty]

We do have a few security lights, but they are on a different meter. If I shut off my main at the meter they stay on. I should mention this is a newer building, so the wiring should be in good shape. (hasn't been hacked up by different tenants over the years)

The wiring is quite simple with only a few circuits - 1 20A for my office, 1 20A for the shop, 1 20A unused for a lighted sign, 1 20A for the shop lights, and 1 30A for my on demand water heater. All 120v.

Even if my neighbor was using my power, I can't think of why there would be a peak at 2AM? The place is a ghost town at night. Could there be something wrong with the meter?

 

[fatboy99]

Is there an outside outlet someone may be plugging into late at night ?

 

[Fifty]

Is there an outside outlet someone may be plugging into late at night ?

No, no outside power.

 

[dadsEH]

Is the Computer doing an auto update/download perhaps???

 

[DesertSparky57]

No mention of air conditioning? Heating? New building without either? Water cooler? Printer? Is the spike every day at 2am or did you leave something plugged in on just one occasion?

 

[HOTFR8]

Sounds like that Smart Meter may not be so smart. Do you have off peak power at that time of night ? Any item faulty ? Can you leave the fridge or a even try turning some items off over night one at a time to see if any of them may be at fault ? If you have one item off and you do not get the peak at 2 am then you know you have something faulty.

Is the Computer left running or in Sleep mode ? If not try turning it off.

 

[Fifty]

Is the Computer doing an auto update/download perhaps???

Not that I know of. It's old so I've got all the background stuff possible turned off. Even if it was updating 500 watts is too much. It only peaks around 80 watts when under load. I left it hooked up to the kill-a-watt overnight so that should have caught any updates.

No mention of air conditioning? Heating? New building without either? Water cooler? Printer? Is the spike every day at 2am or did you leave something plugged in on just one occasion?

No A/C. I have gas heat but it's off for the summer. Nothing attached to the computer - monitor turned off. The peak is not at 2AM every day. Here is a different day, with the peak at a different time...

Sounds like that Smart Meter may not be so smart. Do you have off peak power at that time of night ? Any item faulty ? Can you leave the fridge or a even try turning some items off over night one at a time to see if any of them may be at fault ? If you have one item off and you do not get the peak at 2 am then you know you have something faulty.

Is the Computer left running or in Sleep mode ? If not try turning it off.

No off peak power. I'm going to try leaving one breaker off each day and see what I come up with...

 

[HOTFR8]

Will be interesting to see what you come up with. Although I would be looking at appliances first as breakers may turn off too many items.

 

[socapots]

Will be interesting to see what you come up with. Although I would be looking at appliances first as breakers may turn off too many items.

This is what I was thinking. But certainly a quick way to narrow it down.

 

[Fifty]

Will be interesting to see what you come up with. Although I would be looking at appliances first as breakers may turn off too many items.

I really don't leave anything plugged in besides what I've already mentioned. I'm kinda nuts about unplugging tools when I'm done. I have very few outlets and circuits available, (whoever planned the electrical didn't plan for much) and my office is about empty besides the computer. No appliances besides the fridge and a microwave that I unplug when I'm done.

Maybe I'll buy a clamp on type power meter and see if I can find a draw without anything plugged in on a circuit.

 

[Gary S]

Read this thread about GFCI receptacles. If you have a bunch of them, and they are sucking power 24/7, your lost power could be there.
http://garagejournal.com/forum/showthread.php?t=209624

I have enough GFCIs in my garage that they are eating 1.5kwh per day.

 

[Teken]

If I was a betting man I would guess its your fridge kicking on into defrost mode. My fridge kicks in every 2-3 days to defrost the fridge. The fridge when running is consuming a steady state 114 watts.

When the defrost kicks in, that monster ***** up aprox 500+ watts for about 30-60 minutes depending how much food is in the fridge.

Here is my fridge kicking in at 10:20 PM and it spikes up to 466.80 watts.

This is the daily energy consumption for my fridge:

Teken . . .

 

[Honest Bob]

If the cgfi was sucking down power it would be constant and not only at 2am.

 

[Teken]

If the cgfi was sucking down power it would be constant and not only at 2am.

Yes, I agree.

Teken . . .

 

[2ManyProjects]

My shop is in a commercial building and I have a dedicated 3 phase 208v service. (125 amp) I was looking at the day by day power breakdown from my fancy smart meter, and something isn't adding up. Looking at days where I'm not at the shop, I'm using more than 4 kilowatts.

First, let's get the terminology straight. Per the chart you posted, you're not using anything like 4kW; you're using an average of (very roughly) 200 watts. That draw, over a 24-hour period, equates to (again, very roughly) 4kWh/day. If you want to nail it down more precisely, add up the values for each of those little quarter-hour bars, then divide by 96. I didn't bother.

In any event, the difference between that, and what your K-a-W gadget is telling you isn't really all that much at all: 4.0 kWh/day -- 3.6 kWh/day == 0.4 kWh/day, or only about 16.67 watts on average.

That is easily within the realm of meter-accuracy differences, especially considering that the K-a-W is notoriously bad at measuring inductive loads (cf. <http://forums.anandtech.com/showthread.php?t=137169>), and most (if not all) of the devices you mentioned (particularly the 'fridge and aquarium pump) are in fact inductive loads.

I would also be somewhat suspicious of the accuracy of that so-called "Smart Meter" at very low loads, at least in terms of the minute-by-minute readings (most of the "cycling" pattern evident on alternate quarter-hours MIGHT even be the meter itself self-correcting for accumulated intermediate resolution errors as it averages out usage over the longer haul).

Bottom Line: This whole thing could very easily just be a case of "stacked tolerances". The fact that this is three-phase service, and the legs are probably rather unevenly loaded when the total loads are this small, could also be complicating things, depending on exactly how that meter works.

Where is that extra 500 watts going?

Nowhere. It's at least mostly a figment of your imagination, partially inspired by bogus K-a-W readings.

This is the hour by hour graph from the power company. Are those peaks my fridge kicking on and off?

Could be. But note that most of those "peaks" are simply cycling between 0.04 kWh and 0.06 kWh on alternate quarter-hours. That is the equivalent of about an 80-watt load cycling on and off -- not all that much, really.

I'm not sure what that big peak around 2AM could be?

Does your refrigerator have an icemaker? Is your computer running a semi-recent version of Windoze (i.e., with "Windows Update" enabled)?

Given the untrustworthy nature of the absolute readings, the size of the "peak" doesn't concern me, really; but the fact that it's showing elevated usage that's lasting upwards of an hour or more does seem a bit "off". If there is anything to be suspicious of here, that's it.

 

[2ManyProjects]

If I was a betting man I would guess its your fridge kicking on into defrost mode. My fridge kicks in every 2-3 days to defrost the fridge. The fridge when running is consuming a steady state 114 watts.

When the defrost kicks in, that monster ***** up aprox 500+ watts for about 30-60 minutes depending how much food is in the fridge.

BINGO!!!

You posted this as I was composing my reply; and indeed, I'd wager that explains that one hour or so of elevated usage. So, to the OP: Ignore what I said about that being something to worry about:

Given the untrustworthy nature of the absolute readings, the size of the "peak" doesn't concern me, really; but the fact that it's showing elevated usage that's lasting upwards of an hour or more does seem a bit "off". If there is anything to be suspicious of here, that's it.

I am now satisfied that there is NOTHING wrong with your usage.

 

[A_Pmech]

No off peak power. I'm going to try leaving one breaker off each day and see what I come up with...

You do realize you can't even buy a gas station soda for the amount of electricity you're talking about, right?

I think you're going a little overboard considering the magnitude of the "loss" which, as Projects pointed out, is likely within the error range of the equipment.

 

[rancherbill]

Here are some tings that might be sucking power.

GFCI
Water heater / furnace / AC - anything that has a thermostat (controls are always on monitoring temp and the 28v transformer is always on)
Chargers even when there is no battery plugged in - cordless tool, cell phones etc.
Security lighting - indoor outdoor
Emergency lighting is always charging.
Convenience lighting.
Computers with atx style power supplies (99.9%) never are fully off, even if you select the shutdown option, they are in lower power mode to keep the processor in the CPU alive so that it can instantly power on. Look at the back of your computer and you will see an LED on.
TVs etc that have an instant on feature.
Attic fans etc.
Air handlers.
Compressors with air leaks will turn on when not in use.

There are more things, but, I can't remember them right now.

 

[Teken]

My shop is in a commercial building and I have a dedicated 3 phase 208v service. (125 amp) I was looking at the day by day power breakdown from my fancy smart meter, and something isn't adding up. Looking at days where I'm not at the shop, I'm using more than 4 kilowatts.

I don't have much plugged in, and I've been checking the things I leave on with my kill-a-watt meter.
Computer - 1.58kwh/day
Fish tank - .26kwh/day
Fridge - 1.62kwh/day
That's only 3.46kwh/day. Still missing more than .5kwh! As best I can tell nothing else is on or even plugged in after I leave. My fridge is old, but my kill-a-watt says it only uses 1.62kwh/day, and that was a hot day.

Where is that extra 500 watts going? I'm starting to wonder if some of my wires aren't powering something in the neighbor's shop. (same building) Should I complain to the power company?

This is the hour by hour graph from the power company. Are those peaks my fridge kicking on and off? This is from a day where nobody was at the shop. I'm not sure what that big peak around 2AM could be? There are no lights on when I am not there, besides the fish tank. (20 watts)

I would like to add the following. Without having the ability to monitor *each* circuit in the home. You will need to be very aware of the electrical *Signature* of each load.

The only method to ensure an accurate *static* awareness of the electrical signature is to monitor each branch circuit over an extended period of time. This assumes quite a few things and assumes you're willing to invest the time to do so.

1. Turn off all breakers and monitor one at a time. Keeping notes as to what loads are present.

2. You must monitor those loads over a minimum of 24 hours and in real world usage scenarios. Otherwise you will never truly know the energy signature and the load / consumption that load presents.

3. As the other member stated: You have no method to determine the accuracy of the smart meter and how that data is captured and than rendered to you.

Meaning that meter could be 100% accurate but the guy who created the software which you see could be off 1-5%.

Ask me how I know?

4. To help you narrow down the level of accuracy. Turn all of the breakers off, and have only one *known* load present. A 100 watt light bulbs would be ideal. You will than sit there for two hours and with only the 100 watt light bulb and see what the smart meter presents you.

Teken . . .

 

[Teken]

Here are some tings that might be sucking power.

GFCI
Water heater / furnace / AC - anything that has a thermostat (controls are always on monitoring temp and the 28v transformer is always on)
Chargers even when there is no battery plugged in - cordless tool, cell phones etc.
Security lighting - indoor outdoor
Emergency lighting is always charging.
Convenience lighting.
Computers with atx style power supplies (99.9%) never are fully off, even if you select the shutdown option, they are in lower power mode to keep the processor in the CPU alive so that it can instantly power on. Look at the back of your computer and you will see an LED on.
TVs etc that have an instant on feature.
Attic fans etc.
Air handlers.
Compressors with air leaks will turn on when not in use.

There are more things, but, I can't remember them right now.

Only next to the fridge the hot water tank is a source of unexpected power spike. How often the HWT kicks in to recovery state depends upon several factors.

1. How old and what type of HWT

2. The set point of the HWT

3. How well insulated the HWT is.

4. How often hot water is called upon.

5. How large the HWT is.

Below is my hot water tank:

You will see that I have high lighted just one of the five spikes captured by my GEM energy monitor. The HWT kicked in for a few minutes to maintain the
set water temp.

As you can clearly see it spikes 3559.80 watts. Please keep in mind the *mean average* for that period is only 228 watts RMS. You will see on the left hand side where that spike is extended.

That is my GF taking a bath and as you can see the duration of power consumption is much longer. As the HWT must replace all of the hot water she just consumed.

This is the daily HWT consumption: As you can see the amount of energy varies with daily life and how the family uses the hot water.

I just wanted to give you another perspective as to the fact. You must be very aware and know your electrical loads intimately. Otherwise you're simply guessing as to what it could be. As others said you should be aware of any vampire draws that either kick in randomly, or are in place but could be failing.

Teken . . .

 

[Fifty]

First, let's get the terminology straight. Per the chart you posted, you're not using anything like 4kW; you're using an average of (very roughly) 200 watts. That draw, over a 24-hour period, equates to (again, very roughly) 4kWh/day. If you want to nail it down more precisely, add up the values for each of those little quarter-hour bars, then divide by 96. I didn't bother.

In any event, the difference between that, and what your K-a-W gadget is telling you isn't really all that much at all: 4.0 kWh/day -- 3.6 kWh/day == 0.4 kWh/day, or only about 16.67 watts on average.

I'm not an idiot, I can do simple math. I have other graphs from the power company that show the daily totals, and they're over 4kwh when I'm not there. It's not even the same every day, which is also concerning. Some days it's almost 5kwh.

I'm not even sure if my fridge has a defrost, it's an early 90s model. (no icemaker) I'll leave the kill-a-watt hooked up to it for a few more days to see.

You do realize you can't even buy a gas station soda for the amount of electricity you're talking about, right?

I think you're going a little overboard considering the magnitude of the "loss" which, as Projects pointed out, is likely within the error range of the equipment.

That's more than 15 kilowatts a month! I could run all my shop lights for 2 full work days! I need to know if there is something actually using this power or if the power company is wrong. If I'm not using it I'm not paying for it every month, I don't care if it's 15 watts. They already **** me enough as it is for a commercial account. That's not an acceptable loss for a brand new fancy smart meter. If every meter did that imagine how much extra the power company would make?

If this was a house full of chargers and appliances etc etc etc then I wouldn't be concerned. My problem is that I'm using 4-5 kilowatts a day for an empty cold dark quiet shop!

 

[Milton Shaw]

Older refigs used a defrost timer that was a set defrost time and set run time between defrosts. For instance 30 minute defrost every 12 hours run time. New smart refigs use a control board that counts door opening and time open, last defrost time etc to determine how often to defrost. Some will defrost only once every 5 days in limited usage. That spike appearing every night would indicate older refig that is very inefficient. You would not save enough electricity to pay for a new refig from that few cents worth of usage each day.

 

[Teken]

I'm not an idiot, I can do simple math. I have other graphs from the power company that show the daily totals, and they're over 4kwh when I'm not there. It's not even the same every day, which is also concerning. Some days it's almost 5kwh.

I'm not even sure if my fridge has a defrost, it's an early 90s model. (no icemaker) I'll leave the kill-a-watt hooked up to it for a few more days to see.


That's more than 15 kilowatts a month! I could run all my shop lights for 2 full work days! I need to know if there is something actually using this power or if the power company is wrong. If I'm not using it I'm not paying for it every month, I don't care if it's 15 watts. They already **** me enough as it is for a commercial account. That's not an acceptable loss for a brand new fancy smart meter. If every meter did that imagine how much extra the power company would make?

If this was a house full of chargers and appliances etc etc etc then I wouldn't be concerned. My problem is that I'm using 4-5 kilowatts a day for an empty cold dark quiet shop!

I think you're jumping the gun on your overall KWH consumption total. Based on the charts you provided. It looks like you have one spike which lasts for only a brief period of time.

Unless your chart is incorrect?

Can you provide other charts for a longer period of time? Like for the last 3-4 months? That would give you a better idea to track some of frequency.

Teken . . .

 

[HOTFR8]

Sounds like you need to try with the Fridge off for a start. Turn it off and defrost it yourself as you can do that on in about half an hour on a good hot day and not create problems for any food you have in the Fridge. After trying that it should not go into defrost mode at night.

 

[where2]

Just put your Kill-A-Watt back on the fridge for several days, rather than for just 24 hours. You'll see if it is closer to what you expect, and I agree with Teken and expect it is the defrost cycle causing the spike. "Early 90's" is not an "old" fridge. The "1970" fridge I grew up with had auto-defrost, good old Frigidare". I've had more modern over/under refrigerators with broken defrost elements, but that's a different story. In college, in the early '90s, we called that fridge "The ice age". The avacado green refrigerator that came with my house when I bought it from the original owner in 1998 had auto-defrost.

 

[A_Pmech]

That's more than 15 kilowatts a month! I could run all my shop lights for 2 full work days!

Or about a buck fifty a month...

 

[zuk123]

Worry more when you are running 8 tons of AC in Houston all summer. THAT adds up.

At .10c / KWh it's just not worth the time you are spending.

FWIW, my guess was going to be water heater (until you said it was on demand.) I shut off the breaker to mine to save a little bit of $.

Funny thing is, I actually did call the power company about my apartment in Cali. I was gone for months at a time, and usage seemed way high. The first thing the CSR asked me was if I had a water bed. Totally forgot about the water bed heater. (Not your issue I know.)

It's not impossible that you are powering something outside your unit, just unlikely. Go there at night, flip off your main. See if any landscape or security lighting goes off. If not, put it down to measurement error and walk away from it.

Life is short.

zuk

 

[HOTFR8]

Any updates to report ?

 

[wyliesdiesels]

Tagging on to this thread, cause I'm curious!

 

[Teken]

Still no update?

Teken . . .