load calculation
- Thread starter dbcooper
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bphgravity
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Re: load calculation
They are both one in the same. It depends on how you want to do the math.
10-amp X 125% = 12.5-amp
or
10-amp + 25% = 12.5-amp
In the second equation "10-amp" is the 100%. Either way you are increasing the value by 25%.
[ June 10, 2003, 02:13 PM: Message edited by: bphgravity ]
They are both one in the same. It depends on how you want to do the math.
10-amp X 125% = 12.5-amp
or
10-amp + 25% = 12.5-amp
In the second equation "10-amp" is the 100%. Either way you are increasing the value by 25%.
[ June 10, 2003, 02:13 PM: Message edited by: bphgravity ]
bphgravity
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- Florida
Re: load calculation
See Example D1(b) in ANNEX D of the 2002 code. This shows the 25% increase being added to the service calculation.
What is reasoning behind thinking this is not required?
[ June 10, 2003, 03:29 PM: Message edited by: bphgravity ]
Bob, I do not agree. 220.14 redirects you to 430.24 which does require this factor.
See Example D1(b) in ANNEX D of the 2002 code. This shows the 25% increase being added to the service calculation.
What is reasoning behind thinking this is not required?
[ June 10, 2003, 03:29 PM: Message edited by: bphgravity ]
Re: load calculation
bphgravity
I see what you are what you are referring too. 430.24 is speaking to circuits with more that one motor. I'm not sure what this example is trying to say. Notice that above, the load for the 230 volt A/C and the 115 volt A/C is NOT increased by 25%. Also if you will look at example D2b and D2c, the A/C units are added at 100% load to the total.
Look at 220.30B4, 220.30C 1-6 and 220.31A and B.
Rather that multiply the A/C load by 1.25, it is accounted for by using 100% of the first 10 kva and 40% of the remainder.
bphgravity
I see what you are what you are referring too. 430.24 is speaking to circuits with more that one motor. I'm not sure what this example is trying to say. Notice that above, the load for the 230 volt A/C and the 115 volt A/C is NOT increased by 25%. Also if you will look at example D2b and D2c, the A/C units are added at 100% load to the total.
Look at 220.30B4, 220.30C 1-6 and 220.31A and B.
Rather that multiply the A/C load by 1.25, it is accounted for by using 100% of the first 10 kva and 40% of the remainder.
bphgravity
Senior Member
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- Florida
Re: load calculation
430.24 only requires you to raise the highest rated motor by 25%. In the case of the example in the NEC, that is the 12-A A/C. The other motor loads will be at 100%.
As far as your reference to 220.30......, these are the optional methods for Part III of Article 220. Part II is the standard method that does require the rule of 430.24. Part II and Part III should not be mixed. You must used one or the other to form your calculation.
430.24 only requires you to raise the highest rated motor by 25%. In the case of the example in the NEC, that is the 12-A A/C. The other motor loads will be at 100%.
As far as your reference to 220.30......, these are the optional methods for Part III of Article 220. Part II is the standard method that does require the rule of 430.24. Part II and Part III should not be mixed. You must used one or the other to form your calculation.
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