Single Family/Multi-Family/Commercial service Load Calculation.

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Konen

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Hey all, I just took my General Admin test and past 2/3 sections on it. I failed the service load calculation section by 1 question... I have looked all over the internet, and I can't seem to find any books or websites that have practice service calculation questions. I have been looking for 2 days, I bought 2 books already off of amazon that I thought would help but their practice questions are small, nothing compared to what was on the administrative test. Any guidance would be greatly appreciated, thank you!
 
Just from experience, I know Mikes Holts Master electrician prep has some multi family service load calcs. I believe both standard/optional methods.
 
Can anyone help me understand a calculation in Annex D.

Example D4(b) Optional Calculation for Multifamily Dwelling

I thought using the optional calculation method, you do not apply the demand factor to general lighting or to the Range etc, until you have all loads except A/C or heat. Then first 10k @ 100% and the remaining at 40%. In this example though, it looks like it's standard and throwing me for a loop 😅
 
Rather than these convoluted calculations that end up being so conservative that you are never likely to see anywhere near the load that is calculated, why not come up with something that is closer to what is really going to be seen?
 
petersonra said:
Rather than these convoluted calculations that end up being so conservative that you are never likely to see anywhere near the load that is calculated, why not come up with something that is closer to what is really going to be seen?
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This test is full of oddball load calcs that would never be seen in real life.

Sent from my SM-S367VL using Tapatalk
 
petersonra said:
Rather than these convoluted calculations that end up being so conservative that you are never likely to see anywhere near the load that is calculated, why not come up with something that is closer to what is really going to be seen?
Click to expand...
If I create my own calculation, I will not be able to check my calculations to see if I am correct 😅. I get what your saying and after I get these calculations down to a T, I wouldn't mind doing that, but I'm still trying to be 100%
 
When you calculate the demand load on the service of a single family or multi- family dwelling using the optional method of calcultion. Then you want to calculate the neutral load, is there a way to do it using the optional method? I'm under the assumption that you have to calculate the neutral load using the standards calculation method process.
 
Konen said:
When you calculate the demand load on the service of a single family or multi- family dwelling using the optional method of calcultion. Then you want to calculate the neutral load, is there a way to do it using the optional method? I'm under the assumption that you have to calculate the neutral load using the standards calculation method process.
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I’m pretty sure you are correct in having to do the standard calculation to figure the neutral load.
 
Thanks for you response, I'm not responding quickly but I am reading responses and getting back to studying.
 
Another one I am not seeing an answer too: When calculating the VA for Multi-outlet assemblies. For both simultaneously and non-simultaneously I'm under the assumption you can add you total VA to your Gen Rec load and then apply T220.44 demand factors. Would that be correct?

This is the first 10k @100%
Remainder at 50%
 
Konen said:
Another one I am not seeing an answer too: When calculating the VA for Multi-outlet assemblies. For both simultaneously and non-simultaneously I'm under the assumption you can add you total VA to your Gen Rec load and then apply T220.44 demand factors. Would that be correct?
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See 220.44
 
Ray Mullins books, Electrical Wiring-Rwsidetial, and Electrical Wiring-Commercial, from Delmar-Cengage, both go into service load calcs in great detail.

They were an immense help to me.

Electrical Wiring Commercial (MindTap Course List): Simmons, Phil, Mullin, Ray C.: 9780357137697: Amazon.com: Books

Electrical Wiring Commercial (MindTap Course List) [Simmons, Phil, Mullin, Ray C.] on Amazon.com. *FREE* shipping on qualifying offers. Electrical Wiring Commercial (MindTap Course List)
www.amazon.com




I have no personal, professional, or fiduciary affiliation with Ray Mullins, Delmar-Cengage, or any bookseller.
 
Seven-Delta-FortyOne said:
Ray Mullins books, Electrical Wiring-Rwsidetial, and Electrical Wiring-Commercial, from Delmar-Cengage, both go into service load calcs in great detail.

They were an immense help to me.

Electrical Wiring Commercial (MindTap Course List): Simmons, Phil, Mullin, Ray C.: 9780357137697: Amazon.com: Books

Electrical Wiring Commercial (MindTap Course List) [Simmons, Phil, Mullin, Ray C.] on Amazon.com. *FREE* shipping on qualifying offers. Electrical Wiring Commercial (MindTap Course List)
www.amazon.com




I have no personal, professional, or fiduciary affiliation with Ray Mullins, Delmar-Cengage, or any bookseller.
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Since you have this book, I'm digging into commercial loads right now. I have a question.

It says on page 203(top left paragraph), "However, if the actual load connected is greater than the calculated load, a 125% demand factor must be added to the connected load for those loads that are considered to be continuous."

My question is, is this correct? I have been under the assumption that you compare the calculated load, using the unit load multiplier (which 125% factor is included) TO THE connected load after you apply the 125% demand. It is sounding like you compare it before the 125% factor. Then, if larger, apply 125%.

Thanks for the book recommmendation too btw
 
We’re still on the 2017 here in California, but this is my understanding of it:

Suppose a 4000 SF fire station.

Minimum would be 5200 VA. (1.3 va/sf). Starting with 2020, this will include the 125%.

Now suppose that after looking at plans and specs for the actual lighting that will be installed, it comes out to 4900 VA. You will now need to add the 125% to the 4900 to determine actual load.

Because it’s included in the table, but you’ll need to manually include it in your actual load calcs


I think thats what you’re asking.
 
Seven-Delta-FortyOne said:
We’re still on the 2017 here in California, but this is my understanding of it:

Suppose a 4000 SF fire station.

Minimum would be 5200 VA. (1.3 va/sf). Starting with 2020, this will include the 125%.

Now suppose that after looking at plans and specs for the actual lighting that will be installed, it comes out to 4900 VA. You will now need to add the 125% to the 4900 to determine actual load.

Because it’s included in the table, but you’ll need to manually include it in your actual load calcs


I think thats what you’re asking.
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Yeah it was, it was just worded strangly in this book, made it sounds like you compare unit load VA (1.25% included) to bare bones installed lighting VA. THANKS!
 
Seven-Delta-FortyOne said:
We’re still on the 2017 here in California, but this is my understanding of it:

Suppose a 4000 SF fire station.

Minimum would be 5200 VA. (1.3 va/sf). Starting with 2020, this will include the 125%.

Now suppose that after looking at plans and specs for the actual lighting that will be installed, it comes out to 4900 VA. You will now need to add the 125% to the 4900 to determine actual load.

Because it’s included in the table, but you’ll need to manually include it in your actual load calcs


I think thats what you’re asking.
Click to expand...
Do you know if they have an answer key available to cross check answers. I've looked online and can't find anything, unless it's in the book and I'm just not seeing it 🤦‍♂️
 
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