EC&M’s Electrical Calculations Handbook

We all frequently need electrical reference material, and

sometimes we need an explanation of how certain electrical

equipment works, what dimensions are acceptable or unacceptable,

or approximately which values of things such as

voltage drop or wire size are reasonable. I have observed over

the years that there are certain electrical engineering and

design resources that I refer to more frequently than any others.

In my work I have also noticed that there are certain

types of calculations that are important enough to occur frequently,

but not frequently enough for me to have memorized

all of the dimensional or output data associated with them.

In addition, making calculations without reference values to

“go by” sets the stage for errors that could have been avoided

if similar calculations could be referred to. Finally, there is a

need for good explanatory material that can be shared with

fellow engineers or designers or with owners. Such information

is invaluable in helping them to make sound decisions,

since most thinking individuals can make a good decision

when given the correct data to consider.

It was with all of these in mind that I conceived of this

electrical calculations handbook. It is intended to be a

handy tool that provides in just one place much of the information

that one normally seeks from reference manuals; it

also provides solved “go-by” problems of the most-oftenencountered

types in the electrical industry to expedite

solutions and make calculations easy. Instead of simply providing

formulas without explanations, I took care to explain

each problem type and formula, and to prepare step-by-step

solutions. The problems covered in this book range from

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explanations of Ohm’s law and generator sizing, to lighting

calculations and electrical cost estimating and engineering

economics calculations. I made every effort to make the

book concise enough to be portable, while still including

the very best graphic illustrations. I also included, following

this preface, a detailed listing of problem types in alphabetical

order to make finding the proper “go-by” calculation

easy and fast.

I sincerely hope that you will find that keeping this “electrical

calculation reference library in one book” close by will

save you from having to carry several other reference

books, and that it will expedite your work while making it

easier and more accurate. I hope that the knowledge and

insight gained from it will add even more fun to your work

in our terrific electrical industry.

John M. Paschal, Jr., P.E.