Innovating Electrical Engineering Calculations

Earth fault loop impedance test : Earth fault loop impedance testing is performed to measure the impedance of the earth fault loop in an electrical circuit. The purpose of this test is to ensure that the electrical installation is safe and can operate properly under fault conditions. During the test, the circuit is energized and a test current is injected into the circuit. The voltage drop across the circuit is measured, and the impedance of the earth fault loop is calculated using Ohm's Law. If the earth fault loop impedance is too high, it may result in a high fault current, which can cause the protective device, such as a circuit breaker, to trip. If the impedance is too low, it may not allow enough current to flow to operate the protective device, which can result in a dangerous situation. During the test, the circuit may be tested with both trip and no-trip conditions. The trip condition involves the activation of the protective device, which is designed to disconnect the circ

  Excel_ing CAD - HYPERLINK, HATCH, ENCIRCLE We can add HYPERLINK in AutoCAD drawing in a predefined way using Excel.  HYPERLINK ADDRESS TO AREA OR OBJECT HATCHING UNDER BOUNDARY WITH CONDITIONAL COLORS ENCIRCLE THE TEXT AND MASK Prerequisite to apply our formula in the specified drawing : Get the Coordinates where we want to define the values as text/object. ( Explained in Part-1 ) The area can be defined with 4 coordinates in a CAD file. HYPERLINK ADDRESS TO AREA/OBJECT Hyperlink Formula:  ="(command ""-hyperlink"""&" "&""""&"I"&""""&" "&""""&"A"&""""&" "&""""&[@X]&""""&""""&[@Y]&""""&""""&[@LINK]&""""&""""&&qu

  Excel_ing CAD - BLOCK We can add blocks in AutoCAD drawing in a predefined way using Excel.  BLOCK WITH DYNAMIC ATTRIBUTES IN THE TABLE BLOCK WITH DYNAMIC VALUE ON EACH ITEM Prerequisite to apply our formula in the specified drawing : Get the Coordinates where we want to define the BLOCK. ( Explained in Part-1 ) Create a user-defined BLOCK and save it for reference

  Excel_ing CAD - TEXT/MTEXT We can add text in AutoCAD drawing in a predefined way using Excel.  NORMAL TEXT IN THE SELECTED LAYER TEXT AS PER CONDITIONAL COLORS TEXT ON SPECIFIED LAYERS TEXT AT A PARTICULAR DISTANCE Prerequisite to apply our formula in the specified drawing : Get the Coordinates where we want to define the values as text/object. ( Explained in Part-1 ) Set the style of text as per requirement. ( COMMAND: "ST" ) NORMAL TEXT IN THE SELECTED LAYER Fx ="-TEXT "&[@[X-COORDINATE]]&","&[@[Y-COORDINATE]]&" "&[@ROTATION]&" "&[@TEXT] RESULT = -TEXT 2717612.8821,-1817752.3676 0 MH-1

Excel_ing CAD - Layer Management Prerequisite to apply our formula in the specified drawing : Autocad drawing Coordinates Simple Excel Formulas Steps to get coordinates of Text/Object in AUTOCAD : Select Text/Object ⇒ Select Similar ⇒ Isolate objects (To get minimum items to be extracted) ⇒ DATAEXTRACTION ⇒ Create a new data extraction ⇒ next ⇒ save (with any name anywhere) ⇒ Select objects in the current drawing ⇒ Enter (After selecting Desired area) ⇒ Next ⇒ Select the objects to extract data from  ⇒ Next ⇒ Select Properties needed  (Must select Geometry also to get coordinates)   ⇒ Next ⇒  Next ⇒ Output data to external files  (.xls type)  ⇒ Specify the path ⇒ Next  ⇒ Finish

  Breaker Size : Example: Design Current for the R-TPN Load of Max 10 KW value is 20.89 A We need to select the Next Higher size of Breaker available in the Market for Calculated Design Current (=20.89 A) Here In our Case 30/32 A breaker can be selected. It can be MCCB or MCB or RCBO depending upon requirements. Ib = 21 A In = 30 A Iz = 52.48 (From Cable Data) Note: The operating characteristics of a device protecting a conductor against overload shall satisfy the following two conditions: Ib <= In <= Iz I2 <= 1.45 Iz Ib = the current for which the circuit is designed, e.g. maximum demand In = the nominal current of the protective device Iz = the continuous current-carrying capacity of the conductor (see the AS/NZS 3008.1) I2 = the current ensuring the effective operation of the protective device and may be taken as equal to either— (a) the operating current in conventional time for circuit breakers (1.45 In); or (b) the fusing current in conventional time for fuses (1.6 I

  Design Current : kVA and KW : kVA = KW / PF ; Let's say the power factor is 0.8 , which means KW is 80% of kVA For a 10 KW Load, kVA would be 12.5 kVA "Consequently, we can calculate the Current as well. "

Let's calculate the BUSBAR size of the panel together with the short circuit

 Brief Calculation for earthing : Protective Conductor Sizes. Regulation 543.1.1: This can be achieved by either calculation (543.1.3) or selected (543.1.4) from Table 54.7. The formula used in 543.1.4 for calculating the size of a protective conductor is covered in great detail in a session inside our 17th edition BS7671. Selecting from Table 54.7 The protective conductor size is relative to the size of the line conductor which is represented by the letter 'S. Also, the far right column can usually be ignored as this is only used when the protective conductor and line conductor are of different materials.