ELECTRICITY I

SUBCOURSE STATES ARMY ENGINEER SCHOOL AN ELECTRICAL MATERIALS LIST I AN ELECTRICAL MATERIALS TAKEOFF LIST I EN 5140 B State US Army Engineer School Leonard Wood Missouri 65473 Credit Hours Date September 1999 OVERVIEW subcourse is designed to teach the student the identification of electrical symbols the use of materials and the skills necessary to extract information from a electrical print and legend are no prerequisites for this subcourse subcourse reflects the doctrine which was current at the time this subcourse was prepared In your work always refer to the latest official publications otherwise stated the masculine gender of singular pronouns is used to refer to both men and LEARNING OBJECTIVE will learn to identify electrical symbols extract information from an electrical and legend and list electrical materials by type size and amount will be given this subcourse and an Army Correspondence Course Program examination response sheet demonstrate competency of this task you must achieve a minimum score of 70 on the subcourse examination OF CONTENTS Overview i Instructions iii and Certification Instructions iii Prepare an Electrical Materials Takeoff List 1 A Electrical Symbol Identification 2 B Print Verification 6 C Print Legends 8 D List of Electrical Materials 14 E Service Entrance Requirements 15 Exercise 17 Key and Feedback 22 A List of Common Acronyms A 1 B Recommended Reading List B 1 C Metric Conversation Chart C 1 Inquiry Sheets AND CERTIFICATION INSTRUCTIONS This subcourse contains a multiple choice examination covering the material in the After studying the lesson and working through the practice exercise complete the examination your answers in the subcourse booklet then transfer them to the ACCP examination response Completely black out the lettered oval which corresponds to your selection A B C or D Use No 2 pencil to mark your responses When you complete the ACCP examination response sheet mail in the preaddressed envelope you received with this subcourse You will receive an examination score the mail You will receive two credit hours for successful completion of this examination PAGE IS INTENTIONALLY LEFT BLANK AN ELECTRICAL MATERIALS TAKEOFF LIST Task 051 246 1101 DESCRIPTION this lesson you will learn to identify electrical symbols interpret electrical prints use print legends prepare an electrical materials takeoff list MTOL LEARNING OBJECTIVE will learn to identify and extract information from an electrical print and legend prepare an electrical MTOL will be given the material contained in this lesson You will work at your own and in your own selected environment with no supervision will correctly answer questions on the practice exercise at the end of the lesson The material contained in this lesson was derived from FM 5 424 STP 5 51R12 SM TM 5 303 and TM 5 704 beginning an electrical job materials must be ordered Materials are ordered on a bill of BOM The BOM is based on the MTOL In order to prepare an electrical MTOL you must how to identify electrical symbols and extract information from an electrical print and legend A ELECTRICAL SYMBOL IDENTIFICATION symbols are divided into four areas panels and circuits switches convenience outlets general outlet Figure 1 shows electrical symbols used in panel and circuit outlets Figure 2 page 3 shows common equipment use 1 Electrical symbols in panel and circuit outlets 2 Equipment with panel and circuit outlets There are about 20 different switch symbols Switches are generally characterized by the S and then further identified by an additional letter or number The symbols used in this are those most applicable to military use Figure 3 page 4 shows electrical symbols in outlets Figure 4 page 4 shows their common equipment use 3 Electrical symbols in switch outlets 4 Equipment with switch outlets Figure 5 shows electrical symbols in convenience outlets Figure 6 shows their common use 5 Convenience outlet symbols 6 Equipment with convenience outlets General outlets have the widest variety of symbols In some cases the same symbol may more than one meaning Figure 7 shows symbols in general outlets Figure 8 page 6 shows their equipment use 7 Electrical symbols in general outlets 8 Equipment with general outlets B PRINT VERIFICATION must be able to read and understand an electrical print in order to verify its and correctness Each print has areas known as the legend and the diagram The legend detailed and general information as well as the scale of the print The diagram contains symbols ad indicates where each device is to be installed Figure 9 is an incomplete print of an electrical wiring diagram In the upper left corner of D15 one switch is shown Several switches are needed for this circuit This could have several either one switch controls all the lights on the circuit one switch controls all the lights in one or one switch controls all the lights in both rooms Any questions or problems with prints should addressed immediately to avoid project delays 9 Incomplete print of an electrical wiring diagram One method of performing a complete check of a print is to isolate an individual circuit or Once isolated follow the entire circuit checking for errors Continue this process until all circuits checked Refer to Figure 10 Begin with circuit A1 indicated by the small home run arrow and the line in the opposite direction to the end of the circuit Circuit A1 is missing switches for the lights in the large room and the light in the small room It is also missing a junction box where A1 and A2 join The electrician should resolve any questions or misunderstandings about the before ordering the materials or beginning the work 10 Isolated circuit C PRINT LEGENDS information is found in the legend The legend is located in the lower right corner of the print The schedule of drawings as shown in Table 1 is the part of the legend that identifies the drawings by number gives the description of each and lists the number of sheets per drawing general notes also provide additional information but normally this information pertains to the electrical project rather than individual circuits 1 Print legend print scale can be either graphic or ratio Figure 11 Each segment of line in the graphic scale 1 foot of actual space on a ratio scale 1 8 inch equals 1 foot of actual