Residential Load Calcs PLEASE HELP!!

[msext]

Thank you all in advance.

Ok I have taken thelast part of this administrative test for my residential now 5 times. there are only 4 questions on the exam and I always miss it by 1. I have heard that WA state and AK are the only 2 states that ask these type of questions and also when it comes to a duplex you have to consider it to be a triplex.

Here are the 2 questions with the answers can someone please help me and show me where I am going wrong.

I know there have been several posts about this and thesame typicalasnwer with the step by step shows up but thats not helping. Can someone walk me thru it please.

Question 1

Duplex 1350 sq ft.
7 kva range
5 Amp garbage disposal
11 Amp Dishwasher
3 KW Hot water tank
15KW wall heat
2- 21amp 240V A/C

Standard answers Optional
200 207
217 217
227 227
234 237

Question 2

40 unit 1000 sq ft.
8 KVA range
.6 KVA garbage disposal
1.2 KVA Dishwasher
2.5 KVA Hot water tank
120 Volt 18 Amp A/C

***No house or laundry load to be used in calculation***

Standard answers Optional
1435 955
1596 966
1755 978
1950 989

Thank You

Mike

 

[jtester]

Re: Residential Load Calcs PLEASE HELP!!

I'm not sure I thoroughly understand the data. If each duplex is 675 sq ft and they don't have laundry facilities in the units, if each unit has one HVAC unit and each has 15 KW of heat, I come up with 51,948va/216 amps for the service for both. I am also not sure what your answers are in, amps?
If you can correct me, and let me know how to read the choices for answers, I can give you a step by step method.

 

[msext]

Re: Residential Load Calcs PLEASE HELP!!

Sorry for the data being all over and missing. Here is the data again. The answeres in the left column are standard and the second row are optional method answers. The questions are to be figured each way. Where I am confused is howto do (220.320 figure it as a triplex.

Question 1

Duplex 1350 sq ft each unit.
7 kva range
5 Amp garbage disposal
11 Amp Dishwasher
3 KW Hot water tank
15KW wall heat
2- 21amp 240V A/C

Standard answers Optional
200 A 207 A
217 A 217 A
227 A 227 A
234 A 237 A

Question 2

40 units 1000 sq ft each.
8 KVA range
.6 KVA garbage disposal
1.2 KVA Dishwasher
2.5 KVA Hot water tank
120 Volt 18 Amp A/C

***No house or laundry load to be used in calculation***

Standard answers Optional
1435 Amps 955 Amps
1596 Amps 966 Amps
1755 Amps 978 Amps
1950 Amps 989 Amps

 

[peter]

Re: Residential Load Calcs PLEASE HELP!!

We had a class of about 25 people and we had one of these problems. Every answer was different! I almost had it but the instructor said to include a dryer even though one wasn't mentioned.
In any event the entire Article 220 could be replaced by:
Apartment = 100 amp service
House = 200 amp service
Big House = 400 amp service
But to answer your question, I got 244 A for the optional calc and 228 for the standard calc. Seeing as how the 244A does match anything but the 228 is pretty close to answer #3, my vote would be for #3. If this is multiple choice, you only have to do one or the other.
Hint: sometimes it might be easier to run the four supplied answers thru your equation -- do it backwards -- to see what works.
There's an example in Appemdix D you could model on.
~Peter

 

[sky1]

Re: Residential Load Calcs PLEASE HELP!!

Mike,
What are the voltages to the individual appliances? What do you mean when you say "when it comes to a duplex you have to consider it a triplex"?
Dave

 

[msext]

Re: Residential Load Calcs PLEASE HELP!!

The voltages are 120V/240V. Also here is what I meant by saying a triplex. (If two dwelling units are supplied by one feeder and the total load is greater than when calculated for three identical units under 220.32 the lesser of the two loads
can be used.)The questions they ask are like the above questions. They ask both standard and optional. I have no idea where I am getting confused at. Any help will be appreciated. I may just go take the 01 general electrical admin test since they ask 7 question and they deal with motors etc.