2017 Master Electrician Ref. vs leaDCalc

Master Electrician Reference (or MER for short) 2017 is your electronic pocket electrician reference guide. MER is for electrical designers, engineers, installers, contractors, facility managers, inspectors, exam candidates, apprentices, electricians, journeymen, architects, and technicians. MER is for people doing residential, industrial, and commercial work. Simply, if you are a Master Sparky or work with electricity in any way, this reference guide is for you! Have you ever lost pages or had damaged pages in your pocket electricians reference? The solution is here: Use MER to keep the most important information easily accessible on your iPhone, iPod Touch, or iPad. MER will even do calculations for you; something your old pocket reference book can't do. MER is divided into the following sections: * Simple Circuits - Ohm's law, series and parallel circuits, capacitance, inductance, impedance, and reactance. * Distributed Systems - Distribution wiring diagrams for 120, 208, 277, and 480 volts, color codes, breaker sizes, light switches and bells diagrams. * Electrical Formulas - Formulas for kVA, kW, and HP. * Color Codes - Color codes for capacitors and resistors. * Motors and Wiring - Standard motor and motor starter sizes, tables of full-load currents, locked-rotor information, overload units, OCPD, nameplate information, synchronous motor speeds, three-phase STAR and DELTA diagrams, three-wire start-stop diagram, motor frame dimensions, and motor enclosure types. * Transformers - KVA ratings for single- and three-phase current, transformer formulas. * Conductor Properties - Conductor tables, AWG and metric wire sizes, twist-on pressure connectors, and wire combinations. * Ampacities - Ampacities in raceway, cable, earth, and free air, and derating tables. * Conduit Fill table * Grounding Sizes - Equipment grounding conductor (EGC) and grounding electrode conductor (GEC). * Metal Boxes - Images and sizes of metal boxes, junction / device boxes, junction / pull boxes. * Voltage Drop calculations * Dictionary of electrician terms * Insulation Charts - Table of cable and wire types * Electrical Symbols * NEMA - Plugs and wiring diagrams, enclosure types, standard underground boxes, standard fuse and breaker sizes, standard pull box / junction sizes, standard gutter and wire-ways, standard switchboards, standard busway, standard busbar ampacity, standard panelboard sizes, and standard disconnect sizes. * Math and Conversions - Formulas for algebra, geometry, fractions, temperature conversion, trig tables, unit conversions, metric prefixes, and conversions between inches and millimeters. * Conduit Bending - Includes the guide "The Master Bender Way" on how to bend conduit. See the Master Bender app or MasterBender.com website for more information. * Conduit Weights * Copper Wire Cost * Hole Saw Sizes * Material Raceway Support * Lighting - Fluorescent, high-intensity discharge, incandescent, LED, and low-pressure sodium. * Standard Tool List * Torque - Lugs, bolts, and screws, tightening torque. * Dry, Damp, and Wet Locations * Hazardous Locations * Wiring Methods * Safety - Lock-out / tag-out (LOTO), and a safety manual and first aid. Most pages contain a general scientific calculator. It is expression based: Just enter an expression and evaluate it. It understands trig and power functions, can convert between radians and degrees, and has built-in basic constants like pi and e. MER includes key NEC tables from the National Electrical Code (NEC) 2017. We also have MER apps available for NEC 2011 and NEC 2014 code years. Visit our website at MasterSparky.com for more information.

Application based on the Western Electric Co. Inc, Bell Laboratories, Bell System DC Power Lead Calculator which is in a circular slide rule format.   Using allowable voltage drops specifically designed for telephone company central office direct current power plants and distribution wiring. The application references 48 volt battery systems but also works for other direct current voltages such as 24 volt. When using for 24 volts or other, choose by the required loop voltage drop instead of the specific section of the circuit. Notes: 51. Voltage drop and wire size calculations are based on 2.00 volt LOOP drop from the power plant battery to the load equipment and return. 1.75 Final Volts Per Cell or 40 volts min. operating volts at the equipment for nominal 48V systems.
 (40 + 2 = 42 / 24 = 1.75fvpc) 

 52. LOOP length is used in the calculations, often the battery and returns are unequal length. The result VD is shown as ONE WAY.

 53. The formula used in the lead size calculations is:
CM = LoopLength * 11.1 * Fuse or Breaker @ 100% / VD
(T-Mobile does use 80% of the input breaker or fuse size to calculate DC power wires)
CM = LoopLength * 11.1 * Fuse or Breaker @ 80% / VD
For example the Bell System might use the leaDCalc recommended 66% of the input breaker or fuse size to calculate DC power wires. The Bell System terms Peak and Busy Hour are antiquated electro-mechanical switch central office terms so leaDCalc recommends using 66% of the input fuse or breaker size, ie. 600A fuse or breaker calculate using 400 amperes and which is exactly as was done at Western Electric Co., Inc. for Bell System Telephone offices. 54. BDFB is a Battery Distributing Fuse Board. Fuse Panel is rack mounted at or near the load equipment. Load Equipment is the actual device requiring power. 

 55. This application is intended for informational use. Based on the original Bell System Lead Calculator, Western Electric Co., Inc. Model GS-5420, 4-66.

 56. "leaDCalc" is NOT affiliated with any person or company or anything else anywhere. No how, no way. 
Especially NOT T-Mobile nor the Bell System or even Western Electric Co. Inc., all of whom are mentioned. 
This application is meant as a guide only in determining the size and or capacities of power wiring used in direct current (DC), charging and storage battery telephone systems. 
This application is NOT intended to decide what type of wire, (or if you should even use wire or busbars in your DC systems), no how, no way and it is not for use with alternating current (AC) systems.