Load Calculations Help

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JDB3

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San Antonio, Texas
A "Bible School" has asked me to do some trouble shooting at their complex, consisting of cafeteria, administration bldg., chapel, tabernacle, dorm housing, etc..

In over 30 years in the trade, I have yet to calculate anything of this nature. I do not know if anything was ever originally engineered with all of the buildings in mind or if buildings were added at a later time.

Is there a great site to go to for help in calculating this? Anything would be greatly appreciated.

Thanks very much! :)
 
I am confused. You speak of troubleshooting and you speak of calculating. Those two activities don't normally take place together. Also, I don't recall a project in which I had to "calculate" anything for an existing facility. If I am adding load, I will usually do a 30 day load study, rather than try to calculate the existing load.

What are you being asked to do at this site?
 
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JDB3 said:
A "Bible School" has asked me to do some trouble shooting at their complex, consisting of cafeteria, administration bldg., chapel, tabernacle, dorm housing, etc..

In over 30 years in the trade, I have yet to calculate anything of this nature. I do not know if anything was ever originally engineered with all of the buildings in mind or if buildings were added at a later time.

Is there a great site to go to for help in calculating this? Anything would be greatly appreciated.

Thanks very much! :)
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What you really want, is not clear. but if you want to find out the load, you can do as Charlie said or

Another way, find out the peak time in 24 hrs, take a equipment such as figure and measure the the amperage of each main feeder of buildings , and then do your estimation.

Trey Ratcliff Portfolio - 064.jpg
 
Sorry about the lack of information. The Church that I attend will start meeting at this location. The person in charge of leasing some of the facility to us stated that when there is a lot of activity there, he rents generator ran construction lights. There is existing outside lighting that has been disconnected due to added load problem (he said).

Before I start connecting/repairing existing lighting, I want to verify that it would not pose additional problems. Of course, this would need to be done with a very tight budget.

Just at a glance I saw an overhead CT service. I found 2 panels at different locations in one building. They had 1/2 size breakers, which kind of scared me to begin with.

I have not opened anything up yet, so there may be a situation with connections, length of runs, etc. Just trying to prepare ahead of time for what may be found.
 
charlie b said:
If I am adding load, I will usually do a 30 day load study, rather than try to calculate the existing load.
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You must have some very easy clients to work with. If I told one of our clients I needed to monitor their electric service for 30-days prior to getting them drawings, I would probably get the typical response of "I need the drawings yesterday." :)
 
JDB3 said:
Sorry about the lack of information. The Church that I attend will start meeting at this location. The person in charge of leasing some of the facility to us stated that when there is a lot of activity there, he rents generator ran construction lights. There is existing outside lighting that has been disconnected due to added load problem (he said).

Before I start connecting/repairing existing lighting, I want to verify that it would not pose additional problems. Of course, this would need to be done with a very tight budget.

Just at a glance I saw an overhead CT service. I found 2 panels at different locations in one building. They had 1/2 size breakers, which kind of scared me to begin with.

I have not opened anything up yet, so there may be a situation with connections, length of runs, etc. Just trying to prepare ahead of time for what may be found.
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It also sounds like you want to get some idea whether the service is really too small for the calculated and real load or else the service is not delivering what it should in terms of amps and Voltage Drop numbers.
I would put an amp clamp on branches and feeders to see how much is actually connected when you turn things on.
 
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To add to golddiggers post I have used an amp meter on the phases and turn everything on that would normally be on. If the a/c is the larger load then I would turn that on, all the lights and any other motors etc. My bet is you will be fine.
 
There are approximately 15 buildings on this property. I am still trying to find out if they are all served from this one service or what. :?

As they are used for a variety of different things (administration, dorm, cafeteria, worship services, classrooms, etc.) a lot of different items come into play.

I was able to look at the service briefly yesterday. I "sure" hope that no inspection was done, an apprentice probably would have turned down the original service, much less, the "disconnects" that appear to have been added. :cry:
 
JDB3 said:
There are approximately 15 buildings on this property. I am still trying to find out if they are all served from this one service or what. :?

As they are used for a variety of different things (administration, dorm, cafeteria, worship services, classrooms, etc.) a lot of different items come into play.

I was able to look at the service briefly yesterday. I "sure" hope that no inspection was done, an apprentice probably would have turned down the original service, much less, the "disconnects" that appear to have been added. :cry:
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you should know full knowledge of its distribution type. If there is no drawings or live Survey, it is difficult to guess everything,
 
JDB3 said:
A "Bible School" has asked me to do some trouble shooting at their complex, consisting of cafeteria, administration bldg., chapel, tabernacle, dorm housing, etc..

In over 30 years in the trade, I have yet to calculate anything of this nature. I do not know if anything was ever originally engineered with all of the buildings in mind or if buildings were added at a later time.

Is there a great site to go to for help in calculating this? Anything would be greatly appreciated.

Thanks very much! :)
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its allowed in our area. we usually just get peak load analysis from utility provider to determine load then add additional load that should tell you if the service you have can even support the load you need. its an idea.
 
Yeah, like above. Just call poco and ask them for a 1 yr peak reading. They will even tell you which month (usually always july). I'd be suprised if they only had 1 service by the way your describing place. Compare that to service and add any new loads to that and your done. Typically, the loads on those old service are dropping from more efficient lighting and hvac, unless their adding wing after wing
 
Cletis said:
Yeah, like above. Just call poco and ask them for a 1 yr peak reading. They will even tell you which month (usually always july). I'd be suprised if they only had 1 service by the way your describing place. Compare that to service and add any new loads to that and your done. Typically, the loads on those old service are dropping from more efficient lighting and hvac, unless their adding wing after wing
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What if they are a bunch of smaller services that have the kwh style meters? As far as I know you can't get peak demand from those and you have to do the 30 day study at each service.
 
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