Reading current usage from utility meter

[de2]

Is there a way to find out facility current usage, load current, from utility meter data?

 

[jaggedben]

Probably depends on the meter as well as how precise an answer you're looking for.

What does the meter tell you? Watts? Voltage?

 

[de2]

this is for a restaurant renovation and I want to find out if existing current usage and additional loads can be handled by the main 600A service.
Here is the picture of the utility meter.

 

[electrofelon]

Is there a way to find out facility current usage, load current, from utility meter data?

Its hard to say. I think it depends on the meter and the utility. I have heard that the meter can be programmed for what it displays. One utility's meter I looked at recently displayed current wattage, and also highest demand. Both fields only had "KW" in front of them but you could tell which one was watts because it would change at least a little bit the next time it came around. I knew the other was demand because I was very familiar with the load profile of the place. It gets more complicated if there are CT's and they didnt write the multiplier on the meter.

 

[victor.cherkashi]

When is maximum demand (summer or winter)? Look into electrical bills these months, most likely utility posts the maximum demand in past several months back.

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[wbdvt]

Ask for the utility bill for past couple of months. Depending on the service rate, there may be the info you are looking for.

 

[kwired]

Call the utility. The meter might not display what you are looking for, but they very possibly have historical data they can get you. Peak demand stored in the meter is likely only from the last 30 days. Peak demand during past year will be in the archives at POCO offices though.

 

[de2]

Call the utility. The meter might not display what you are looking for, but they very possibly have historical data they can get you. Peak demand stored in the meter is likely only from the last 30 days. Peak demand during past year will be in the archives at POCO offices though.

I did called the utility and they are going to let me know if they have this information, waiting waiting and waiting now.

 

[Jraef]

In answer to your question though, you cannot determine current from a watt-hour meter. It cannot differentiate 100kWh from being 1kW for 100 hours or 100kW for 1 hour, it all comes out the same to that meter.

 

[electrofelon]

In answer to your question though, you cannot determine current from a watt-hour meter. It cannot differentiate 100kWh from being 1kW for 100 hours or 100kW for 1 hour, it all comes out the same to that meter.

Yes, but the meter prolly does record demand. As mentioned, likely only last cycle which isn't enough for nec purposes.

 

[dkidd]

this is for a restaurant renovation and I want to find out if existing current usage and additional loads can be handled by the main 600A service.
Here is the picture of the utility meter.

Look at


220.87 Determining Existing Loads. The calculation of a
feeder or service load for existing installations shall be
permitted to use actual maximum demand to determine the
existing load under all of the following conditions:
(1) The maximum demand data is available for a 1-year
period.
Exception: If the maximum demand data for a 1-year period
is not available, the calculated load shall be permitted
to be based on the maximum demand (measure of average
power demand over a 15-minute period) continuously recorded
over a minimum 30-day period using a recording
ammeter or power meter connected to the highest loaded
phase of the feeder or service, based on the initial loading
at the start of the recording. The recording shall reflect the
maximum demand of the feeder or service by being taken
when the building or space is occupied and shall include by
measurement or calculation the larger of the heating or
cooling equipment load, and other loads that may be periodic
in nature due to seasonal or similar conditions.
(2) The maximum demand at 125 percent plus the new
load does not exceed the ampacity of the feeder or
rating of the service.
(3) The feeder has overcurrent protection in accordance
with 240.4, and the service has overload protection in
accordance with 230.90.

 

[adnj]

We usually get the usage data from the client for the year. After that, we ask when the heavy use periods are and check each phase at 15 minute intervals for an hour. We do this on at least two separate days.

But you should be able to calculate load based on the installed devices in the facility and using a diversity factor.



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[de2]

But you should be able to calculate load based on the installed devices in the facility and using a diversity factor.

This is a 4000sqft deli. 3000 sqft of space will be completely renovated 1000sqft of space is remaining the same.
Wiring and the restaurant is about 50 years old. Labels on the electrical kitchen equipment is worn out, no way to tell what is the name plate data is.
Only trustful engineering data I have is 600A service and NEW equipment is 250A.
I was hoping to find out existing current usage.

If utility don't tell me current and demand historical data ,I am planing to rent amp meter and installing it for 30 days.

 

[Jraef]

This is a 4000sqft deli. 3000 sqft of space will be completely renovated 1000sqft of space is remaining the same.
Wiring and the restaurant is about 50 years old. Labels on the electrical kitchen equipment is worn out, no way to tell what is the name plate data is.
Only trustful engineering data I have is 600A service and NEW equipment is 250A.
I was hoping to find out existing current usage.

If utility don't tell me current and demand historical data ,I am planing to rent amp meter and installing it for 30 days.

That's about the best approach, but also consider any seasonal variations that might be involved. If they have A/C, and October is getting cool already, the usage in August might be a lot higher. But what you COULD do is estimate it by looking at your peak current in October, then compare the kWH for August vs kWH in Oct, and use the same differential factor factor to adjust the peak current. So for example Oct. use is 400kWH, August was 700kWh, the differential is 175%. Oct. peak current is 300A, so assume August peak might be as high as 300A x 1.75 = 525A. Not perfect, but better than a total WAG.

 

[de2]

ConEd said they do not record Amp usage. I said GE meter has the ability to report Amp value, ConEd insisted that they dont record this.


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[electrofelon]

ConEd said they do not record Amp usage. I said GE meter has the ability to report Amp value, ConEd insisted that they dont record this.


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You get the KW value and convert it into amps. Usually people will throw in another bit of fudge on that for less than unity power factor and/or imbalance, but the code doesnt seem to require it. I guess they figure the extra 25% is enough.

 

[de2]

You get the KW value and convert it into amps. Usually people will throw in another bit of fudge on that for less than unity power factor and/or imbalance, but the code doesnt seem to require it. I guess they figure the extra 25% is enough.

How would you estimate this;
1.) 35000kwh avarage electric usage per 30 days
2.) Service cable and ocpd rated 600A.
3.) This is a very busy deli, 4000sq ft.

So how much Amp they are using avarage?

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[gar]

181003-2214 EDT

de2:

I have not read this whole thread. Early on I thought it make sense to make some actual current measurements, as well as power measurements. But I did not comment.

Seeing your last post I have a wild guess based on the limited information and assuming a resistive load.

The meter is 4 wire 120 V from an earlier photo. This implies 3 phase wye.

Using your 30 day data and assuming the deli is operational 2/3 of the day.

35,000,000 divided by 30 = 1,166,667 watt-hour per day

Assume equal load on each leg and we have 389,000 watt-hour per leg per day. Or 16,208 watt-hr per hour for a 24 hour day. But assuming operation for only 2/3 of a day this means we use 16,208*3/2 = 24,312 watt-hr per hour for a 20 hour day per leg.

Divide 24,312 by 120 for current on each leg which = 203 A.

Quite likely peak average current is greater.

Working form this as a check 203*120 =24,360 watts per phase. 24,360*20 = 367,200 watt-hours per phase per 20 hour day. For a 30 day month this is 367,200*30 = 14,616,000 watt-hours per month per phase. For three phases this is 14,616,000*3 = 43,848 kWH. Since I rounded at various points this is a good check.

Monitor current with a recording ammeter, and see what typical values are.

.

 

[electrofelon]

How would you estimate this;
1.) 35000kwh avarage electric usage per 30 days
2.) Service cable and ocpd rated 600A.
3.) This is a very busy deli, 4000sq ft.

So how much Amp they are using avarage?

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gar gave the answer of how to make an educated guess from this info, but the key is, you need DEMAND in KW not KWH. Demand is the highest average KW usage in a (usually) 15 minute interval. Nearly all commercial customers get demand billing so the utility should be able to furnish this data. It will also be on the power bills if the client has them.

 

[kwired]

How would you estimate this;
1.) 35000kwh avarage electric usage per 30 days
2.) Service cable and ocpd rated 600A.
3.) This is a very busy deli, 4000sq ft.

So how much Amp they are using avarage?

Sent from my SM-G892U using Tapatalk

This:

gar gave the answer of how to make an educated guess from this info, but the key is, you need DEMAND in KW not KWH. Demand is the highest average KW usage in a (usually) 15 minute interval. Nearly all commercial customers get demand billing so the utility should be able to furnish this data. It will also be on the power bills if the client has them.

Unless customer is subject to demand penalties they might not put demand data on the bill, but they still likely have that data available if you ask for it. Small commercial services, 200 maybe even 400 amp, might not be subject to demand penalties. Larger services may be assessed a demand charge that you pay whether you use what is included in that charge or not. Those also will detail the usage demand.