NEC Load Calculations (26301-20): Questions/Answers
Continuous loads are calculated at what percentage of the maximum current
rating of the overcurrent protective device? Right Ans - 80%
The NEC requires that the ampacity of branch circuit conductors can be de-
rated when there are more than how many current carrying conductors in a
Raceway? Right Ans - 3
Conductors must be de-rated when installed in conduit _____ . Right Ans -
on or above rooftops
What is the current carrying capacity for number 6 THWN aluminum
conductors in conduit run through an ambient temperature of 38 degrees C?
(96-104 degrees faranheit) Right Ans - Ampacity of aluminum THWN =
50A [NEC Table 310.15(B)(16)] Correction factor = 0.88 [NEC Table
310.15(B)(2)(a)]
•50A x 0.88 = 44A
What is the voltage drop for a 120 Volt single phase two wire branch circuit
100 feet long using copper conductors of 6530 circular mills with a non-
continuous load of 13 amps? Right Ans - •VD = (2 x 100' x 12.9 x 13A) ÷
6,530CM VD = 5.14V
•Calculate the load center length for a 208 Volt four wire three phase branch
circuit with the following fixed non continuous loads
•load A 60 amps at 45 feet from the source
•Load B 40 amps at 60 feet from the source
•load C 30 amps at 75 feet from the source
•load D 25 amps at 100 feet from the source Right Ans - 63.55ft
•Calculate the load center length for a branch circuit consisting of the
following non-continuous loads:
•125 amps at 80 feet from the source
•75 amps at 110 feet from the source
•50 amps at 100 feet from the source Right Ans - 93ft
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LeCrae. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $8.99. You're not tied to anything after your purchase.