Cable Size Spreadsheet
The cabling spreadsheet uses the relationship between cable gauge and resistance to help the user in specfying an electrical installation that will meet his requirements.
The user can operate the sheet in one of three ways:
1) Replicate the ABYC (American Boat and Yacht Council tables) that provide the required cable gauge given voltage and allowable voltage drop - either 3% or 10% or anything in between
2) Compute the actual voltage drop for an installation consisting of a number of runs of possibly different types of cables and lengths
3) Compute the wire gauge in a single run installation required to meet a user specified voltage drop
An example of the ABYC formatted tables is shown in the following figure. The user enters the parameters of his installation (yellow cells)- Temp, System Voltage and cable type and the spreadsheet computes the cable gauge (Blue cells) for various combinations of amps and cable length.
An example of an installation that uses multiple runs of different gauge wire is shown in the following figure. This example is for a windlass application. Typically in these applications a very heavy gauge wire is used for the long runs from the batteries to the windlass and back but the actual connection to the Windlass is made with light gauge wire typically 10 gauge. As shown in blue in the table the short 10 gauge runs have approximately the same voltage drop of 0.12 volts as the longer 30 ft runs of the heavy gauge wire. It has always seemed strange that they would sell the windlasses with such light wire. This particular installation does not meet the ABYC recommended voltage drop of 3% and the windlass will not work as well as it could even though 2/0 wire was used at a large expense.
Cable Size Software Download To download the software from YachtSoftware.org click in the table below.
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| Item | Version Number | Type Of Document | Link to Download |
Estimator | Version 4.0 | Excel Spread Sheet | CableSize.xls |
| | | |
Notes on running the software
The software is Excel based software backed up by a very powerful Visual Basic program. The Visual Basic program is called a Macro by Microsoft and they automatically issue a warning when a spreadsheet containing a Macro is started to help reduce the probability of spreading viruses. Macros are widely used thoroughout the world, however, and particularly by the engineering community where they are safe and secure. The following Microsoft approved procedure allows you to enable Macros on a case by case basis so you can run the Designer and still maintain security for other applications. To do this follow the simple steps outlined below
Start Excel
Click Tools on Toolbar at top of sheet
Click Options
Click Security Tab
Click Macro Security
Click Medium Security which means that you can choose whether or not to run Macros instead of disabling Macros for all applications
Click OK
To start the Isoftware click on download link above and save the software in a convenient folder of your choosing. Start Excel, open the file, enable Macros in the dialog box that comes up, and you are off and running.
Copy Right and Distribution
All the software is copyrighted and you do not have permission to include any parts of the code or Web Page for use in your own products without permission. You do not have permission to distribute the software. When publishing results in a forum please include a reference to http://YachtSoftware.org