Electrical Exam Calculation Rounding Rules

Calculations on the electrical exam do not always result in whole number answers. Choosing the correct answer will depend on whether you understand the rules for rounding. Consider the following example:

Question:

How many 15 ampere rated general lighting branch circuits are required to supply a 5000 square foot single family dwelling?

A. 9 circuits

B. 8 circuits

C. 7 circuits

D. 6 circuits

Solution:

A. 9 circuits.

= 5000 sq.ft. x 3 va/sq.ft./120 volts x 15 amperes

=15000 va/1800 va

=8.333 circuits or 9 Circuits (round up)

It is not possible to run a fractional portion of a circuit. The greater the number of circuits run the less the chance of overload. So whenever there is a remainder as part of your answer (even if the remainder is less than .5) round up to the next whole number.

Knowing how to answer these kinds of exam questions is key to passing the electrical exam. Prepare for success. Click on the “Register Now” tab or call 888-919-3926 today.