Demand load for store

[horizon7]

A store with outside dimensions 36 feet by 125 feet applied by a 120/230volt single phase service with the following equipment -

2 - 3 hp AC units 230 volts
1 - 12kw furnace 230 volts (blower motor included in 12kw)
2 - 2.5kw water heaters 230 volts
1 - 30 amp copy machine 230 volts
3 - 12 foot show windows
1 - 1500 vA sign
55 - duplex receptacles

What is the total calculated demand load for this store?
Is it - 202
- 212
- 252
or - 268

 

[George Stolz]

We won't do your homework for you. What do you think the answer is, qualify your answer, and we will verify and help you.

 

[hunter94]

reply

reply

I'm not doing homework I'm studying for master exam and I don't have much exp. On commercial calculations.I'm thinking I would use 13500va for lighting and 9000 for the show window and 7460va for the AC omitted the heat 9900va for the receps I came up with 212 amps

 

[LarryFine]

Start by consistently using 240v instead of 230v for line-to-line voltage.

 

[Smart $]

I'm not doing homework I'm studying for master exam and I don't have much exp. On commercial calculations.I'm thinking I would use 13500va for lighting and 9000 for the show window and 7460va for the AC omitted the heat 9900va for the receps I came up with 212 amps

I didn't check your calculation. For one, show us how you get from loads in VA to Amps. FWIW, you are also missing [at least] one other consideration. You can learn a lot in this area by studying the examples in Annex D of the NEC.

 

[brother]

A store with outside dimensions 36 feet by 125 feet applied by a 120/230volt single phase service with the following equipment -

2 - 3 hp AC units 230 volts
1 - 12kw furnace 230 volts (blower motor included in 12kw)
2 - 2.5kw water heaters 230 volts
1 - 30 amp copy machine 230 volts
3 - 12 foot show windows
1 - 1500 vA sign
55 - duplex receptacles

What is the total calculated demand load for this store?
Is it - 202
- 212
- 252
or - 268

NEC 2008
36 feet by 125 feet =36 x 125= 4500 x 3 (Table 220.12)=13500
2 - 3 hp AC units 230 volts = Table 430.248 FLC 17 X 240=4080 x 2= 8160 (omit 220.60)
1 - 12kw furnace 230 volts (blower motor included in 12kw)=12,000
2 - 2.5kw water heaters 230 volts=2500 x 2=5000
1 - 30 amp copy machine 230 volts= 30 x 240= 7200
3 - 12 foot show windows= (220.14 G) 200 x 12=2400 x 3= 7200
1 - 1500 vA sign=1500
55 - duplex receptacles(220.14 I) = 55 x 180 = 9900

Non continous loads=

furnance 12,000
water heaters 5000
copy machine 7200
receptacles 9900

Total Non continous=34100

continous loads=

general Lighting 13500
show window 7200
sign 1500

Total continous (215.2 A) = 22200 x 1.25=27750
plus non continous 34100
Total 61850

61850/240=257.7 or 61850/230=268.91 is closest answer. go with 268 I used 120/240 because alot of tests uses the nominal voltage NEC 220.5. I haven't tried it all they way through with just 230volts.

So experts of Mike Holt Forum, was I correct in this calc??

 

[Smart $]

NEC 2008
36 feet by 125 feet =36 x 125= 4500 x 3 (Table 220.12)=13500
2 - 3 hp AC units 230 volts = Table 430.248 FLC 17 X 240=4080 x 2= 8160 (omit 220.60)
1 - 12kw furnace 230 volts (blower motor included in 12kw)=12,000
2 - 2.5kw water heaters 230 volts=2500 x 2=5000
1 - 30 amp copy machine 230 volts= 30 x 240= 7200
3 - 12 foot show windows= (220.14 G) 200 x 12=2400 x 3= 7200
1 - 1500 vA sign=1500
55 - duplex receptacles(220.14 I) = 55 x 180 = 9900

Non continous loads=

furnance 12,000
water heaters 5000
copy machine 7200
receptacles 9900

Total Non continous=34100

continous loads=

general Lighting 13500
show window 7200
sign 1500

Total continous (215.2 A) = 22200 x 1.25=27750
plus non continous 34100
Total 61850

61850/240=257.7 or 61850/230=268.91 is closest answer. go with 268 I used 120/240 because alot of tests uses the nominal voltage NEC 220.5. I haven't tried it all they way through with just 230volts.

So experts of Mike Holt Forum, was I correct in this calc??

Looks good (didn't scrutinize though)... but a couple exceptions. One, the 252 answer is closer to accurate NEC calc's using nominal 240 voltage (257.7-252=5.7 vs. 268-257.7=10.3). Second, are you going to furnish horizon7 with stealth com devices so you can take his test for him

 

[brother]

Looks good (didn't scrutinize though)... but a couple exceptions. One, the 252 answer is closer to accurate NEC calc's using nominal 240 voltage (257.7-252=5.7 vs. 268-257.7=10.3). Second, are you going to furnish horizon7 with stealth com devices so you can take his test for him

Well, as someone put it, I think it was Charlie. Seeing how I could not find the 'exact' answer, I try to recreate their mistake, and make the same mistake, so I can get graded right even though the answer is not exactly right. Thats why I chose 268

 

[Smart $]

Well, as someone put it, I think it was Charlie. Seeing how I could not find the 'exact' answer, I try to recreate their mistake, and make the same mistake, so I can get graded right even though the answer is not exactly right. Thats why I chose 268

Oh, I understood the why on that issue. I was just pointing out that the calc using 240 was closer to 252.

FWIW, if you calculated through with 230 instead of 240, it would have made a difference of 300VA on the copy machine and the result would have been even closer to 268 (actually, exactly 268 when rounded).

Now, about posting answers for someone's homework or studying for a test... if you need the practice yourself, and want some scrutiny, you could try PM'ing another member.

 

[brother]

Oh, I understood the why on that issue. I was just pointing out that the calc using 240 was closer to 252.

FWIW, if you calculated through with 230 instead of 240, it would have made a difference of 300VA on the copy machine and the result would have been even closer to 268 (actually, exactly 268 when rounded).

Now, about posting answers for someone's homework or studying for a test... if you need the practice yourself, and want some scrutiny, you could try PM'ing another member.

Please find it in your heart to forgive me, I couldnt resist!! lol And yes I was checking my self too in this area. Been thinking about getting a 'admin' license, even though it doesnt look like i will be using it much. Only think really stopping from proceeding is that is it worth it to just say 'I have this card now' and pay that extra money to those STATE people!! lol

 

[Smart $]

Please find it in your heart to forgive me, I couldnt resist!! lol And yes I was checking my self too in this area. Been thinking about getting a 'admin' license, even though it doesnt look like i will be using it much. Only think really stopping from proceeding is that is it worth it to just say 'I have this card now' and pay that extra money to those STATE people!! lol

Hmmm.... I know that feeling

 

[willis 2191]

Looks good (didn't scrutinize though)... but a couple exceptions. One, the 252 answer is closer to accurate NEC calc's using nominal 240 voltage (257.7-252=5.7 vs. 268-257.7=10.3). Second, are you going to furnish horizon7 with stealth com devices so you can take his test for him

thanks for help i passed my masters exam

 

[brother]

thanks for help i passed my masters exam

Hey shouldn't I be in that thank you group?? LOL By the way, how long did the test take, and what state was it in?? Do you plan to use your masters license to start a business.