### Voltage Drop Calculations- Part Six

In article  " Voltage drop calculations- Part One ", I indicated that there are eight methods for Voltage Drop Calculations as follows:

1- Ohm’s Law Method,

2- European method,
3- U.S method which divided to:

• Circular-mils method,
• Chapter (9) tables method.
4- Approximate Mathematical method,
5- Quick On-Line method,
6- Ampere-Feet method,
7- Lookup tables,
And I explained the first two methods: Ohm’s Law Method and European Methods in this Article.

And, I explained the third method: U.S Method- Circular-mils Method In Article
Voltage drop calculations- Part Two  ",

And, I explained the third method: U.S Method- Chapter (9) tables Method In Articles:

And, in Article
Voltage Drop Calculations- Part Four ", I explained the following methods for Voltage Drop Calculations:
• Approximate Mathematical method,
• Ampere-Feet method,
• Lookup tables,

Also, in Article " Voltage Drop Calculations- Part Five ", I explained the Quick On-Line Method with (8) Voltage Drop Calculators.

Today I will continue explaining other methods for Voltage Drop Calculations as follows.

8- Excel Spreadsheets Method for Voltage Drop Calculations

 8- Excel Spreadsheets Method for Voltage Drop Calculations Under this method, I will explain the following excel spreadsheets for Voltage Drop Calculations: First: Excel Spreadsheet for US / NEC Methods: Excel Spreadsheet for Voltage Drop Calculator, Excel Spreadsheet for Voltage Drop Calculations, Siemens Voltage Drop Calculations Spreadsheet. Second: Excel Spreadsheet for European Method /Code Excel Spreadsheet for Cable Sizing, Voltage Drop Calculation and Circuit Breaker Selection, Excel Spreadsheet for 3-Phase Voltage Drop Calculations.

First: Excel Spreadsheet for US / NEC Methods:

 1- Excel Spreadsheet for Voltage Drop Calculator This Excel Spreadsheet Calculate the Voltage Drop as per US- Circular Mils Method. How to use this Excel Spreadsheet: 1- Put the input data which are: Voltage in Volts, Load Current in Amps, Distance in Feets, Cable Cross section Area in Cmils. Note: if you have the Cable Cross section Area in AWG/Kcmil use the shown table to get the equivalent Cmils. 2- Get Voltage drop (V D) in V from the following Formula: Voltage drop (V D) 3 Phase = 1.73 X I X L X K / Cmils Voltage drop (V D) Single Phase = 2 X I X L X K / Cmils Where K=12.6 for CU and K=21.2 for AL 3- Get Voltage drop (V D) in percent from the following Formula:  (V D) % = Voltage drop (V D) in V x 100 / Voltage 4- From the Results section, select the Result that match with the actual method of installation from the following choices: Copper and 3 phase, Aluminum and 3 phase, Copper and single phase, Aluminum and single phase. 5- If the (V D %) > the predetermined Value according to Country Regulations (2.5 % or 3%), change the Cable Cross section Area in Cmils with a higher size.

 3- Siemens Voltage Drop Calculations Spreadsheet  This voltage drop calculator will provide an approximate value for use in project design. You can review this spreadsheet in the Previous Article "Siemens Voltage Drop Calculations Spreadsheet ".

Second: Excel Spreadsheet for European Method /Code

1- Excel Spreadsheet for Cable Sizing, Voltage Drop Calculation and Circuit Breaker Selection

This Excel Spreadsheet Calculate the following as per European Method /Code:
• Cable Sizing,
• Voltage Drop Calculation,
• Circuit Breaker Selection

How to use this Excel Spreadsheet:

First: for Cable Sizing

1- Put the input data (as in below image) which are:

• No Load Voltage (Uo) in Volts,
• Power Factor (P.F),
• Rated Voltage (Vn) in Volts,
• Ambient Temperature in C deg. (to be selected from the drop down menu),
• Max. Conductor Temperature in C deg.,
• Route length of Cable (L) in meters,
• Load Power (PL) in watts. Input Data

2- Get the Rated Current (IL) in Amps from the following Formula:
IL = PL / ( √3 x Vn x PF ) Steps #2 to 4

3- Select the suitable Cable Size (in mm2) from the Drop down menu with the following condition:
The Cable Ampacity (IZ) > the Rated Current calculated from step #2 above.

4- If the selected Cable Ampacity < the Rated Current calculated from step #2 above, a warning Message in red color will appear telling you that the selected cable cross section is small and you must re-select a higher size from the drop down menu.

5- Select the installation method and details from the drop down menus which are required to Derate the selected cable Size according to the actual installation conditions. Step#5

6- Get the Air Temperature and Grouping Derating Factors based on step#4 above.

7- Get the corrected (De-Rated) Current in Amps from the following Formula:

De- rated current of Cable = Air Temp. Factor x Grouping Factor x Rated current of Cable Steps#6 to 8

8- If the De- rated current of Cable < Rated current of Cable x Over capacity factor, a warning Message in red color will appear telling you that the selected cable cross section is small and you must re-select a higher size from the drop down menu of step#3.

9- Repeat the above steps till you didn’t get any warning messages.

Second: Voltage Drop Calculations(see below image)

1- Put/get the input data which are:

• AC Resistance of Cable (RAC) in Ω/Km,
• Inductance of Cable (X) in Ω/Km,
• P.F = Cos (φ),
• Sin (φ).

2- Get Voltage drop (V D) in V/Amp/Km from the following Formula:
(V D) Voltage drop of cable (L) per Amp. Per length = √3 × (R (AC) 90°×Cos (φ) + X × sin (φ))

3- Get Voltage drop (V D) in Volts from the following Formula:
Voltage drop (V D) = (V D x I L x L)

4- Get Voltage drop (V D) in Percent from the following Formula:
(V D %) = (V D cable *100 / V n)

5- if the (V D %) > the predetermined Value according to Country Regulations (2.5 % or 3%),a Warning message in red color will appear telling you that the Voltage Drop % is High and you must re-select a higher size from the drop down menu of step#3 in cable Sizing Section.

Third: Circuit Breaker Selection

1- Select the Circuit Breaker Rating in Amps from the drop down menu to verify the following formula:
Rated Current (IL) ≤ CB Rating ≤ the Cable Ampacity (IZ)

In the next Article, I will Explain More Examples for Cable Sizing, Overcurrent Protection and Voltage Drop Calculations. Please keep following.

 End of Course EE-4

#### 1 comment:

1. جزاك الله خيرا