ElectriCalc® LT An Electrician's Utility for Wiring User's Guide
IMPORTANT NOTE ON USER RESPONSIBILITY Due to the serious nature of electrical installations, the user of this calculator must be certain that he or she is using it correctly, i.e., in accordance with both the following instructions and National ® Electrical Code requirements. This tool was designed to work with the ® 1999 NEC , not replace it. Users, especially those unfamiliar with the Code, should exercise appropriate caution.
Introducing the ® ElectriCalc LT ® The ElectriCalc LT is an invaluable calculator for today’s busy electrical professional. Unlike a regular calculator, it has intuitively labeled “electrical keys” and conforms to the 1999 National Electrical Code, allowing you to solve Code-related problems quickly and accurately.
Table of Contents Key Definitions ................................................. 3 Default Settings .............................................. 16 Basic Math Operations .................................. 17 Percent Calculations...................................... 17 Memory Functions ......................................... 18 Kerchoff’s Law................................................ 19 Ampacity Wire Sizing..................................... 24 Voltage Drop ...................................
Key Definitions Standard Calculator Functions [On/C] — On/Clear Turns on power. Pressing once clears the last entry and the display. Pressing twice clears all non-permanent values. [Off] — Off Turns all power off. Clears the memory and most internal registers. [Set] — Second Function Accesses the secondary functions shown above the keys when pressed prior to selection. [Rcl] — Recall Recalls a value stored in a register (e.g., to recall voltage drop % press [Rcl] [VD%]).
[M+] — Cumulative Memory Adds displayed value to Memory (e.g., 10 [M+], 20 [M+], [Rcl] [M+] = 30). Clears when the calculator is shut off. [Set] [M+] — Memory Minus (M−) Subtracts the displayed value from Memory. [+] [–] [x] [÷] [=] Arithmetic operation keys. [Set] [–] — Change Sign (+/–) Toggles the sign of the displayed value (from positive to negative or from negative to positive). [Set] [÷] — Reciprocal (1/x) Reciprocal, or 1/x function. [0] – [9] & [ • ] Digits used for keying in numbers. 2 [Set] [ .
Mode "Set-Up" Functions [Set] [x] — All-Clear (AC) Resets all settings and values to their default settings. [CU/AL] — Copper/Aluminum Used to toggle between copper (default) and aluminum wire types. When the wire type is revised, any calculated wire size will be re-calculated automatically. If a wire size is entered with the wrong wire type, pressing [CU/AL] will change the material type without changing the size. Displays: Al or Cu [Set] [1] — Single-Phase (1Ø) Sets calculator to single-phase mode.
[Set] [9] — 90°C Wire Insulation Sets calculator to 90°C insulation type for wire size calculations. Displays: 90. [Set] [2] — Ambient Temperature Permanently enters ambient temperature for determining ampacity derived wire sizes. Ambient temperature will only change when entering a new value or by resetting the calculator ([Set] [x]). Defaults to 30°C (86°F). Amb° will display when the ambient temperature is other than 30°C (86°F). Displays: Amb°.
Electrical Functions [kilo-] — KiloThis key is used with watts, amps, volts, and volt-amps to identify "kilo-" values. [Set] [kilo-] — MilliThis key is used with other keys watts, amps, volts, and volt-amps to identify "milli-" values. [Amps] — Amps Enters or calculates amps (using volts and VA or watts). Displays: AMPS, KAMP. [Volts] — Volts Enters or calculates volts (using amps, HPth, and VA or watts). Default value is 240 volts. Displays: VOLT, KV, or mV.
[Watts] — Watts Enters or calculates watts (using amps, volts, and VA or horsepower). Displays: WATT, KW, or mW. [Set] [Watts] —Power Factor Enters or calculates power factor percentage (based on watts and VA). Defaults to 100%. Entered or calculated power factors greater than 100% will result in an error. Displays: PF%. [HPth] — Horsepower (Theoretical) Enters or calculates theoretical horsepower (based on Amps, VA, watts, efficiency%, PF%, and/or volts). 1.
Ampacity Tables The ElectriCalc LT uses NEC Table 310-16 (310-17 for Free Air) to find wire sizes and ampacity ratings of wires. The calculator uses the following data to calculate wire size: 1) insulation temperature rating (60°C, 75°C and 90°C), 2) wire material (copper or aluminum), and 3) ambient temperature. Only standard AWG wire sizes are used by the ElectriCalc LT. NOTE: 1/0, 2/0, 3/0 and 4/0 wires are entered using the [0] key (i.e., 0, 00, 000 and 0000).
♦ Second Press If a wire length has been entered, the second press displays the smaller of the two wire sizes. If not solving for voltage drop wire size, then displays the maximum ampacity. ♦ Third Press If a wire length has been entered, displays the minimum wire ampacity rating. [Set] [WireSz] — 125% Ampacity Operates same as [WireSz], except that a factor of 125% is applied to the amperage.
Displays the maximum adjusted ampacity of the calculated parallel wire size. Displays: WIRE A. NOTE: Some areas may not allow paralleling conductors. Users must know the jurisdiction requirements for their area. [Set] [ParSz] — Derated Wire Size Used to calculate derated wire sizes and allowable ampacity based on the entered quantity of wires, NEC Table 310-16 and NEC Table 310-15(b)(2)(a). Derated wire sizes are not calculated when there are less than 4 wires, or when the unit is in Free Air mode.
Voltage Drop Solutions The ElectriCalc LT will calculate maximum lengths, minimum wire sizes or actual voltage drops given the other two values. Voltage drop solutions are based on the DC resistance values found in NEC Chapter 9, Table 8. NOTE: Voltage drop solutions may vary slightly from actual AC circuit values as factors such as inductive reactance, skin effect, raceway material, etc., are not considered [VD%] — Percent Voltage Drop Used to enter or calculate voltage drop.
[Length] — Length Enters or calculates the maximum length of run for voltage drop computation. Displays: FEET or MET [Set] [Length] — Wire Resistance Displays the wire resistance per 1,000 feet of the wire size in [WireSz] based on NEC Chapter 9, Table 8.
Ground Function Keys [Grnd] — Ground An output-only key used to find the grounding electrode conductor size for AC systems based on NEC Table 250-66 and an entered or calculated service-entrance conductor (largest size). Only actual wire sizes are considered valid entries. ♦ First Press Calculates the copper grounding electrode conductor size if you have entered a valid wire size. Displays: GRND CU WIRE SIZE ♦ Second Press Displays the aluminum grounding electrode conductor size.
[Set] [Grnd] — Equipment Ground (EqGrnd) This function uses NEC Table 250-122 to compute the minimum equipment grounding conductor size, given an entered amperage rating or setting for a over-current device up line (i.e., 300 [Set] [Grnd]). NOTE: This function deviates from the NEC Table 250-122 for Amp values of 4001 or more. The AL conductor sizes given in the Table (1200 MCM AL) are not among those listed in Table 31016/17, which is the table the calculator uses to calculate wire size.
Default Settings When you first receive your calculator, it is pre-set to the default settings listed below. You can always return your calculator to these default values with an All-Clear ([Set] [x]).
Basic Math Operations This calculator uses standard chaining logic, which simply means that you enter your first value, the operator (+, –, x, ÷), the second value and then the equals sign (=). A. B. C. D. 3 3 3 3 [+] [–] [x] [÷] 2 2 2 2 [=] [=] [=] [=] 5 1 6 1.5 Percent Calculations The percent key [%] can be used for finding a given percentage of a number or for working add-on, discount or division percentage calculations. 355 250 25 100 [x] [+] [–] [÷] 15 6.5 5 50 [%] [%] [%] [%] 53.25 266.
Memory Functions Whenever the [M+] key is pressed, the displayed value will be added to memory. Other memory functions: Function Keystrokes Subtract from memory [Set] [M+] Recall total in memory [Rcl] [M+] Display & clear memory [Rcl] [Rcl] Clear memory, no display [Set] [Rcl] Replace memory with displayed value [Set] [Rcl] [M+] The memory is semi-permanent; it will be cleared when you: 1) turn off the calculator; 2) press [Rcl] [Rcl]; 3) press [Set] [Rcl]; 4) press [Set] [x] (all clear).
Kerchoff’s Law The ElectriCalc LT utilizes Kerchoff’s Law in finding volts, amps, volt-amps, watts, horsepower (theoretical), efficiency and power factor. Finding Voltage Find the voltage supply to a singlephase load drawing 14,605 volt-amps and 115 amps. Steps Keystrokes Clear calculator Set to 1-phase Enter volt-amps Enter amps Solve for volts [On/C] [On/C] [Set] 1 14605 [VA] 115 [Amps] [Volts] Display 0. 1 PH 14,605. VA 115. AMPS 127.
Finding Current Load A building with 120/240 volt 1Ø service has the following loads: Range = 7,800 VA Heating = 15,100 VA Dryer = 5,100 VA Fixed Appliances = 8,900 VA General Lighting = 6,470 VA What is the service load (amps) of the circuit supplying this building? Steps Keystrokes Clear calculator Set to 1-phase Add VA loads: [On/C] [On/C] 0. [Set] 1 1 PH 7,800 + 15,100 + 5,100 + 8,900 + 6,470 [=] 43,370 [VA] 43,370. VA 240 [Volts] 240. VOLT [Amps] 180.
Finding Amps from Kilowatts What is the amperage for a 75 kW load connected in a 120/208 volt, 3Ø circuit? Steps Keystrokes Display Clear calculator Set to 3-phase Enter kilowatts Enter volts Solve for amps [On/C] [On/C] 0. [Set] 3 3 PH 75 [kilo-] [Watts] 75. KW 208 [Volts] 208. VOLT [Amps] 208.
Finding kVA Rating What is the kVA rating for a 120/208 volt, three-phase 65 amp transformer? Steps Keystrokes Display Reset calculator Enter volts Enter amps Solve for kVA [Set] [x] 0. 208 [Volts] 208. VOLT 65 [Amps] 65. AMPS [kilo-] [VA] 23.417327 KVA Finding Wattage A 120 volt single-phase 45 amp electrical motor has an 87% power factor. What is its wattage? Steps Keystrokes Clear calculator Set to 1-phase Enter volts Set power fact % Enter amps Solve for watts [On/C] [On/C] 0.
Finding kW Rating What’s the kW rating for a 90 amp, 208 volt, three-phase broiler with 100% power factor? Steps Keystrokes Clear calculator Set to 3-phase Set power factor Enter amps Enter volts Solve for kW [On/C] [On/C] 0. [Set] 3 3 PH 100 [Set] [Watts] 100 PF% 90 [Amps] 90. AMPS 208 [Volts] 208. VOLT [kilo-] [Watts]32.
Ampacity Wire Sizing The required wire size of a service conductor can be determined based on the specified electrical requirements and the [WireSz] key. The wire size is automatically recalculated whenever the wire insulation (temperature) ratings or wire material (copper or aluminum) types are revised. Wire sizing is based on the requirements defined in NEC Tables 310-16 and 310-17. Wire Sizing Based on Insulation Rating Wiring is being installed in a 240 volt, single-phase system rated at 30 kVA.
Re-sizing Wire Based on Different Insulation Ratings What wire size is required for a 75°C copper branch circuit carrying a load of 260 amps? What would the wire size be if 90°C copper is used? Steps Reset calculator Set to 75°C Enter amps Find wire size Change to 90Û Keystrokes Display [Set] [x] 0. [Set] 7 3Ø 75 Cu 0. 260 [Amps] 260.
Wire Sizing Based on Ambient Temperature Find the 90°C aluminum wire size needed to connect a 47,700 volt-amp load to a 240 volt, single-phase source. Steps Keystrokes Clear calculator Set to 1-phase Set to 90°C Set to alum. Enter volt-amps Enter volts Find amps Find wire size [On/C] [On/C] 0. [Set] 1 1 PH [Set] 9 1 Ø 90 Cu 1 PH [CU/AL] 1 Ø 90 Al 1 PH 47700 [VA] 47,700. VA 240 [Volts] 240. VOLT [Amps] 198.
Wire Sizing Based on Material Type Find the wire size for a 75°C copper wire carrying a 3Ø load of 265 amps. What is the equivalent aluminum wire size? Steps Keystrokes Display Reset calculator Set to 75°C Enter amps Find wire size [Set] [x] 0. [Set] 7 3Ø 75 Cu 0. 265 [Amps] 265. AMPS [WireSz] 300 CU AWG WIRE SIZE Change to alum.
Sizing Parallel Conductors What size 60°C insulated copper wire is required for a single conductor carrying a 500 amp load in a Free Air environment (30°C amb. temp.)? What size for 2 parallel conductors? For 3 conductors? Steps Keystrokes Reset calculator Set free air mode Enter amps Find 1 wire size [Set] [x] 0. [Set] 5 3Ø 60 FrAir Cu 0. 500 [Amps] 500.
Finding Derated Wire Size What is the derated wire size required for nine 75°C copper wires, each carrying a maximum load of 65 amps? Steps Keystrokes Reset calculator Set to 75°C Enter amps Find normal wire size [Set] [x] [Set] 7 65 [Amps] Find derated wire size [WireSz] Display 0. 3Ø 75 Cu 0. 65.
Sizing Temperature-Adjusted Derated Wires A circuit was built with 90°C aluminum wire connecting a 47,650 volt-amp load to a 240 volt, single-phase source. Ambient temperature is 50°C. What is the derated wire size required if eight current-carrying THHN wires were installed in the raceway? Steps Keystrokes Display Reset calculator [Set] [x] 0. Set to 1-phase [Set] 1 1 PH Set to 90°C [Set] 9 1Ø 90 Cu 1 PH Toggle to alum. [CU/AL] 1Ø 90 Al 1 PH Enter volt-amps 47650 [VA] 47,650.
Voltage Drop The reduction in voltage between the power source and the load can be determined by entering the phase, volts, amps, wire material, voltage drop wire size and length of run. The calculator determines resistance and then the voltage reduction. Voltage drop can be displayed as volts dropped, or as a percent reduction of potential load. This calculator also finds voltage drop wire size once you have entered or calculated the phase, volts, amps, length, wire type, and allowable VD percentage.
IMPORTANT NOTE ON VOLTAGE DROP CALCULATIONS The ElectriCalc LT calculates voltage drop and wire size using DC resistance values as defined by the 1999 NEC. To find the voltage drop for a specific wire size, you must first enter amps (and the other required variables), then enter the specific wire size. Otherwise, if amps are entered last, the calculator will recalculate the wire size to match the ‘99 NEC Ampacity Table requirements.
Steps Keystrokes Enter wire size 8 [WireSz] Solve volt. drop Solve % v.drop [VD%] [VD%] Display 8 CU AWG WIRE SIZE 3.0 DROP V 1.4 DROP V % Finding Three-Phase Voltage Drop A 20-amp three-phase load is being fed by a 230-volt source located 150 feet away. The installation specifications require 75°C #10 THW stranded copper conductor. What is the voltage drop on this branch circuit? Steps Keystrokes Display Reset calculator [Set] [x] 0. Set to 75°C [Set] 7 3Ø 75 Cu 0. Enter amps 20 [Amps] 20.
Finding Voltage Drop Wire Size A 20-amp single-phase 208-volt load will be located 175 feet away from the source. Assuming a 3% allowable voltage drop, what is the size of 75°C conductor required for this branch circuit? Steps Keystrokes Reset calculator Set to 75°C Set to single ph. Enter amps Enter volts Enter distance Enter allow. VD% Find wire size [Set] [x] 0. [Set] 7 3Ø 75 Cu 0. [Set] 1 1 PH 20 [Amps] 20. AMPS 208 [Volts] 208. VOLT 175 [Length] 175.
Finding Voltage Drop Distance How far from a single-phase 240-volt source can you install a 15 amp load using 60°C #10 Al branch circuit conductors? Assume a 3% allowable voltage drop. Steps Keystrokes Reset calculator Set to single ph. Set to aluminum Enter amps Enter volts Enter wire size [Set] [x] 0. [Set] 1 1 PH [CU/AL] 1Ø 60 Al 1 PH 15 [Amps] 15. AMPS 240 [Volts] 240. VOLT 10 [WireSz] 10. AL AWG WIRE SIZE 3 [VD%] 3. DROP V % [Length] 123.
Finding Voltage Drop Resistance What is the resistance of 85 feet of #2 90°C copper conductor? Steps Keystrokes Display Reset calculator [Set] [x] Set to 90°C mode [Set] 9 Enter wire size 2 [WireSz] 0. 3Ø 90 Cu 0. 2 CU AWG WIRE SIZE Find resistance [Set] [Length] 0.2033993 OHMS WIRE Find 85 ft resist* [÷] 1000 [x] 85 [=] 0.0172889 *NOTE: Given resistance per 1000 feet, divide by 1000 to get a per foot resistance, then multiply by 85.
Ground Conductor Wire Size You can use single or multiple service entrance conductor(s) to find the grounding electrode conductor for AC systems. When using multiple conductors, the ElectriCalc LT uses the equivalent circular mils to find the grounding electrode conductor (based on NEC Table 250-66). Find the grounding electrode conductor wire size required when 2/0 is the largest 3-phase 75°C copper serviceentrance conductor being used.
Equipment Grounding Conductor Wire Size The [Set] [Grnd] keystroke can be used to find the grounding conductor size for raceways and “over-current devices in circuit ahead” equipment. The calculator uses the displayed amperage value to solve for the equipment grounding conductor based on NEC Table 250-122. Find the equipment grounding conductor size required when the circuitbreaker is rated at 45 amps and 90° copper is being used in the installation.
Error Codes The error codes for the ElectriCalc LT are listed below (Note: To clear an error, simply press any key): Error Description 1 Display register overflow (Answer too large to fit display) 2 Invalid or out-of-scale entry 3 PF or EFF calculated above 100% 5 Unable to calculate VDWire Size (Amps/Length too high) 9 Entered or calculated more than 15 different wires sizes 11 Temperature setting out of range for wire computation.
Battery Information The calculator is powered by a single 3Volt Lithium CR-2032 battery. This should last upwards of 800 hours of actual use (1 year plus for most people). If the display becomes very dim or erratic, replace the battery. NOTE: Please use caution when disposing of your old batteries as they contain hazardous chemicals.
Semi-Permanent Values The following semi-permanent values are cleared to default settings when the calculator is shut off: (1) Independent User Memory (2) Free Air mode Warranty Warranty Repair Service – U.S.A. Calculated Industries, Inc. ("CII") warrants this product against defects in materials and workmanship for a period of one (1) year from the date of original consumer purchase in the U.S.
CRACKING OF THE LCD, WHICH ARE PRESUMED TO BE DAMAGES RESULTING FROM MISUSE OR ABUSE. To obtain warranty service in the U.S., ship the product postage paid to the CII Authorized Service Provider listed on the back page of the User’s Guide. Please provide an explanation of the service requirement, your name, address, day phone number and dated proof of purchase (typically a sales receipt). If the product is over 90 days old, include payment of $6.
repair information and charges. Repairs are guaranteed for 90 days. Repair Service – Outside the U.S.A. Not all countries have CII Authorized Service Providers or the same warranty and service policies. To obtain warranty or non-warranty repair service for goods purchased outside the U.S., contact the dealer through which you initially purchased the product.
IN NO EVENT WILL CII BE LIABLE FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RESULTING FROM ANY DEFECT IN THE PRODUCT OR ITS DOCUMENTATION. The warranty, disclaimer, and remedies set forth above are exclusive and replace all others, oral or written, expressed or implied. No CII dealer, agent, or employee is authorized to make any modification, extension, or addition to this warranty.
Legal Notices Software copyrighted and licensed to Calculated Industries, Inc. by Specialty Calculator Technologies, LLC, 1999. User’s Guide is copyrighted by Calculated Industries, Inc., 1999. ElectriCalc LT and Calculated Industries are registered trademarks of Calculated Industries, Inc. ALL RIGHTS RESERVED Calculated Industries, Inc. 4840 Hytech Drive Carson City, NV 89706 U.S.A 775/885-4975 • Fax: 775/885-4949 E-mail: techsup@calculated.com http://www.calculated.com File: 5025-MN.
Designed in the United States of America Printed in Indonesia 5025-MN V1.
