Q: Why does DC Wire Sizer have two User Interfaces (Sizer Wizard and Sizer Pro) for the calculator?

A: Early Alpha testing with many types of users, indicated two distinct user patterns.  Boaters who only occasional added or replaced a wire wanted easy step-through process for sizing a wire.  Professionals and boaters with wiring projects (i.e. rewiring, adding alternative power sources, etc.) preferred the fastest way to calculate and capture the wire run.  The Sizer Pro is optimized for fast entry and designed with advanced feature like more granular analysis of ampacity and voltage drop (VD).   

Q: Why does the Calculated Result re-animate in Green, Yellow and Red?

A: The color used for the calculated Wire Size and Voltage Drop (VD) is a visual way of showing the wire size status.  The calculated results will always be green unless the user changes the Maximum Voltage Drop to be above 1% (ISO) or 3% (North American Standards) or has changed wire size or length in the Edit Results to exceed the original calculated result.   Color Keys:

  • Green has a VD between 1–3% (1% for ISO),
  • Yellow has a VD between 3.1–10%, (ABYC) and
  • Red has a VD greater than 1% (ISO) or 10% (ABYC).
  • The calculated Voltage Drop (VD) percent is the amount of voltage that will be lost over the length of the wire. ISO requires 1% VD for all wiring.  North American marine wiring must be either:

    • Three (3%) for “critical” applications (i.e. bilge pumps, blowers, navigation lights, electronics, panels, etc) or
    • Ten (10%) for “non-critical” (i.e. cabin lights, stereo, etc.).

    Excessive Voltage Drops:

    • Can cause damage or system faults to equipment such as radar, pumps, starters,and other equipment,
    • Can risk overheating wires, potentially leading to a fire,
    • And is inefficient leading to a waste of energy

    Note: The Result field(s) will re-animate for emphasis when the input selection(s) have been changed enough to affect the results. 

    Q: The wire disappeared in the Raw Material Type detail screen after editing the wire size?

    A:  The wire is probably still there, just under another wire type size because the wire size or length was changed in the Edit Results view.  For example, if three wires made up the 12AWG Safety Duplex wire aggregate, and one wire was manually changed to 10AWG; the wire changed to 10AWG is now aggregated under 10AWG Safety Duplex wire tip,e and the 12AWG Safety Duplex will now have only two wires in the list.  This will also occur if the length is changed.  For example, changing the wire length from 10ft to 12ft on a 10amp wire will change the calculated wire size to change from 12AWG to 10AWG.   


    Q: Edit Results - Why is it there and who would use it?

    A: Edit Results provides a more granular analysis of ampacity and voltage drop (VD) as the Wire Size and Length are changed.  On occasion, the wire length might need to be estimated or different options for running the wire might be available.  Only wire sizes with an ampacity greater than the selected “Amps” are displayed.  When adjusting the wire size or length, remember to keep the VD within safe limits (1% ISO or 3% for ‘critical’, 10% for non-critical device for North American).  Any changes will be reflected in the Calculated Results where the color of Wire Size and Voltage drop  should be green unless safe limits were exceeded.

    Note: Edit Results was designed for professionals. We do not recommend manually overriding the calculated results unless you have significant wiring experience.

    Q: What does "Inside Engine Room" mean? 

    A: Engine rooms are assumed to have a higher ambient temperature (50°C/122°F) than outside the engine room (30°C/86°F) and might need a larger gauge wire to have equivalent current carrying capacity (aka Ampacity).  Marine standards use either a different ampacity table or formula for compensating the wire size when the wire is in or runs through the Inside Engine Room.

     Note: Insulation Rated at 60°C (140°F) is not allowed in the engine room.  If Insulation 60°C (140°F) is selected, you will not be able to selected Inside Engine Room unless you increase the Insulation Rating to 75°C (167°F).  The standard Insulation Rating for boat cable is 105°C (221°F)

    Q: When I Email or Export from the Wire Wizard, I only get the Calculation and Input, but not the Saved Description and Project Name?

    A: This is to accommodate users that do not save the wire run, but still want to Email or Export the Calculated Results and Input.  To Email or Export the Saved Wire Run information with wire Description and Project Name, select the wire from the Wire Run tab and tap the Email or Export button on the bottom of the view.  If you would rather be able to print the saved wire run without going to the Wire Run list, let us know by sending  a Feature Request.

    Q. The Raw Material has the Safety Duplex wire length at 21’, but my positive is only 15' and my negative is 21’?

    A:  Duplex wire sheaths the positive and negative together, so the longest length (21’) needs to be purchased.  If the length difference between positive and negative wire lengths is significant, then you might want to consider purchasing two primary wires ( 15’ of red and 21’ yellow’) instead of duplex.

    Q: Is the sample wire runs always there? 

    A: The Wire Run and Raw Material tabs look to see if any wire runs have been added and if not, sample data is created (in projects “Kangaroo” and “Esprit”).   But if you had saved a calculation before ever tapping on the Wire Run and Raw Material tab then no sample data is created.  If the sample wire runs were created, feel free to delete them. 

    Q: When editing the Wire Run list, why would someone “Cancel” vs “Delete” a wire run?

    A: When a wire run is “Deleted”  from the Wire Run list, that wire run is permanently gone.   When you “Cancel” a wire run, its more like ‘suspending' the wire run to a later date.  “Cancel" can also be used when you do not want a wire run to be included in the Raw Material Listed.  Only “Active" wire runs are displayed or summed in the Raw Material list.  So if you prefer to only purchase wire for the wire runs your doing now  and not the wire runs being done much later, you can put the later wire runs into a “cancel’ state.  Later you can change the Cancelled wire runs back to “Active”.  Note:  wire runs in a ‘Cancel’ state are only displayed on the Wire Run ‘All’ list and their easily spotted by the black line through them.

    Q: How does the Raw Material List distinguish between a single wire such as a primary and a multiple wire such as safety duplex?

    A: The application considers ‘primary’ and battery’ to be the only single wires and the remaining wire types are duplex (e.g. safety, bilge wire, twisted pair, etc.) or greater (such as triplex, mast wire,  etc.).

    Q: Why is using the correct size wire along with good marine wire and connectors important?

    A: Corrosion is more likely to occur with un-tinned non-marine quality wire and connectors.  Corrosion increases the resistance and the increased resistance decreases the voltage (aka increases the voltage drop %).  Increased resistance also creates heat and heat decreases the ampacity (aka safe current carrying capacity).  The end result is that the low voltage and higher temperature wires can potentially damaging equipment or worse, create enough heat to cause a fire.  Boaters should annually inspect wire and connect for corrosion.  If you suspect corrosion is impacting a circuit, you confirm it by measuring the voltage at the source while the device is not operating (wire down the volts) and then measure the volts again at the devise while it is operating.  The different in volts should equal the projected voltage drop for the length of the wire (use DC Wire Sizer to look up the voltage drop % and subtract it from the source volts).  Properly sized wire will give you a little cushion against minimal corrosion but skimping on the wire size removes that cushion.


    Q: Why does Sizer Pro have two "Save” buttons; one on the main view and another “Save" button on the Save Wire Run view? 


    A: On the first “Save", the wire calculation is saved.  If you tap the "Save" button on the Save Wire Run view, the wire run info (such as project name, wire description, etc) is saved with the previous wire calculation.  If you tap the "Cancel" button from the Save Wire Run view, the original wire calculation from the first ’Save' is deleted.  The assumption here is that some boaters will only want to quickly save the calculation and default the Project Name and Description name (quick double "Save”) while others will want to enter the wire run information (such as Project Name, Wire Description, etc.) before saving.  In either case, the saved Wire Run can be edited in the Wire Run tab or the Raw Materials tab.

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