I'm trying to complete a load calculation for an existing 7800 sq. foot school building to submit to the local utility company. I am not sure how to go about this given the examples in the back of the NEC. I'm figuring lighting load at 3 watts per sq foot x 1.25. receptacles at 180 VA each. kitchen counter circuits at 1500 watts. larger appliances at namplate ratings, etc.,. AC load at 125%. My question is do I add these all up and thats it, or is there some sort of reduction after a certain amount of volt amps
load calculation for school building
- Thread starter mikewo
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websparky
Senior Member
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- Cleveland, Ohio
Re: load calculation for school building
If you use Example D3 Store Building as your base for continuous and non-continuous and follow 220, you should be able to arrive at your answer.
Work the example calcs until you understand how they work and then replace them with your figures.
When you think you have it, post the info or specific questions and I'm sure someone will help you along!
If you use Example D3 Store Building as your base for continuous and non-continuous and follow 220, you should be able to arrive at your answer.
Work the example calcs until you understand how they work and then replace them with your figures.
When you think you have it, post the info or specific questions and I'm sure someone will help you along!
bphgravity
Senior Member
- Location
- Florida
Re: load calculation for school building
I prefer to use Article 220.34 Optional Method - Schools. Table 220.34 is very easy to use for new construction installations. You may be able to use it for this application.
There is also Article 220.35 for determining existing loads.
I prefer to use Article 220.34 Optional Method - Schools. Table 220.34 is very easy to use for new construction installations. You may be able to use it for this application.
There is also Article 220.35 for determining existing loads.
bphgravity
Senior Member
- Location
- Florida
Re: load calculation for school building
Non-continuous lighting is at 100%
Continuous lighting (3 hours or more) is at 125%
Non-continuous lighting is at 100%
Continuous lighting (3 hours or more) is at 125%
Re: load calculation for school building
mikewo,
Please note that the minimum lighting loads for those occupancies listed in Table 220.3(A) are values to be used in lieu of known loads. If you have a fixture schedule intended to be used for this existing building, then the minimum lighting load for this calculation is the GREATER value of: either the values in Table 220.3(A) OR knwon lighting loads. Those lighting loads are considered continuous loads and are calculated at 125%
If you are looking at 220.34 Optional Method - Schools, please read carefully the criteria which must be met to even use this calculation. You will still figure the sum of the loads according to Part I of Article 220 before applying 220.34
Lastly. The minimum service size (for any calculation) is the sum of the loads on the branch circuits as determined by Part I of Article 220 with applicable demands from Part II, III or IV applied to that sum. (See 220.10)
If you find this confusing you are not alone.
mweaver
mikewo,
Please note that the minimum lighting loads for those occupancies listed in Table 220.3(A) are values to be used in lieu of known loads. If you have a fixture schedule intended to be used for this existing building, then the minimum lighting load for this calculation is the GREATER value of: either the values in Table 220.3(A) OR knwon lighting loads. Those lighting loads are considered continuous loads and are calculated at 125%
If you are looking at 220.34 Optional Method - Schools, please read carefully the criteria which must be met to even use this calculation. You will still figure the sum of the loads according to Part I of Article 220 before applying 220.34
Lastly. The minimum service size (for any calculation) is the sum of the loads on the branch circuits as determined by Part I of Article 220 with applicable demands from Part II, III or IV applied to that sum. (See 220.10)
If you find this confusing you are not alone.
mweaver
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