Help, pulling hair out on this one!!

[The Wire Doctor]

what is the minimum service demand for 10-8kw ranges in an apartment complex?

I have calculated the way I thought it should be done , But still not getting it???????

 

[roger]

Show us how you did it and what you came up with, then we can help you find where you erred and how to find the correct answer.

Roger

 

[jumper]

what is the minimum service demand for 10-8kw ranges in an apartment complex?

I have calculated the way I thought it should be done , But still not getting it???????

see 220 ,table ? you can find it.

 

[The Wire Doctor]

10- 8kw= 80,000watts x.43=34400 or 34.4kw the 43% comes from table220.84 the correct answer is 25 kw in one of my Master exam studybooks but i don't see how it was figured??

 

[roger]

Okay, go back to article 220.55 which will point you to Table 220.55, go to the notes below the table and try to work it out from there.

Be careful when looking at the different columns, A & B are percentages and C is total KW, look for the minimum number.

Use a straightedge to help stay on the right line across the columns.

Roger

 

[Dennis Alwon]

10- 8kw= 80,000watts x.43=34400 or 34.4kw the 43% comes from table220.84 the correct answer is 25 kw in one of my Master exam studybooks but i don't see how it was figured??

I think the range problems can be very tricky but I think you are looking at this incorrectly. 10 ranges--- then look at col. C

 

[The Wire Doctor]

The question says min demand, But the answer in the answer key says 25 kw, column c says 25kw for 10 units? Man i have been staring at this section all afternoon and it is escaping me somehow, could you please work out this one and show how it is supposed to be?:smile:


Question says-the minimum service demand for 10-8 kw ranges in an apt complex would be??

 

[roger]

The question says min demand, But the answer in the answer key says 25 kw, column c says 25kw for 10 units? Man i have been staring at this section all afternoon and it is escaping me somehow, could you please work out this one and show how it is supposed to be?:smile:


Question says-the minimum service demand for 10-8 kw ranges in an apt complex would be??

Part III of article 220 is Feeder and Service Load Calculations and section 220.55 is in this part of the article, the title of table 220.55 is

Table 220.55 Demand Factors and Loads for Household Electric Ranges, Wall-Mounted Ovens,
Counter-Mounted Cooking Units, and Other Household Cooking Appliances over 13/4 kW Rating
(Column C to be used in all cases except as otherwise permitted in Note 3.)

all you have to do is figure which column will give you the lowest value and this would be column C for this particular question.

Roger

 

[roger]

Taking (10) 8 KW ranges using column B would equate to,

10 X 8 KW =80 KW or 80,000 W

80,000 X 34 % = 27,200 W or 27.2 KW

Using column C allows these 10 units to be a 25 KW load, 2.2 KW lower than using column B

Roger

 

[The Wire Doctor]

so 27.2 would be the maximum if it were asked that way right?

 

[Dennis Alwon]

so 27.2 would be the maximum if it were asked that way right?

I don't think it would be asked that way since the max may be construed as 80,000. Why we have an option to use one column over the other is really the question but I think you got the idea.