The calculators and testing tools available on this website (www.ceinspector.com) are provided by Blue Peter Marine as convenience tools to assist marine professionals in their preliminary calculations and assessments.
These tools are NOT part of the International Marine Certification Institute (IMCI) assessment system and are NOT endorsed or verified by IMCI.
These tools are provided "as is" without warranty of any kind, either expressed or implied. While every effort has been made to ensure accuracy, Blue Peter Marine makes no guarantees regarding the correctness, completeness, or reliability of the calculations or results generated by these tools.
Users are solely responsible for verifying all calculations and results independently before using them for any certification, compliance, or construction purposes. Blue Peter Marine explicitly declines any and all responsibility for errors, omissions, or inaccuracies in these tools, and shall not be held liable for any damages, losses, or consequences arising from the use or misuse of these calculators.
All certification decisions must be made by qualified professionals using approved methodologies and verification processes.
Circuit-by-circuit voltage drop for marine AC and DC conductors, with the smallest cross-section that stays inside your target limit.
Launch CalculatorFree to use · Runs entirely in your browser · No data leaves your device
Separate tabs for DC and AC circuits, up to twenty circuits each. DC nominal voltage selectable at 12, 24 or 48 V; AC nominal voltage set to whatever your installation runs at.
Set a standard limit and a tighter critical limit. Tick a circuit as critical and it is measured against the tighter threshold. The volts figure stays the same either way.
For every circuit the tool returns the smallest standard cross-section that holds the drop inside its target, chosen from 0.75 mm² up to 150 mm².
Enter the run either way. One-way lengths are doubled internally so the calculation always uses the full out-and-back conductor path.
Each circuit is flagged OK, CLOSE or OVER as you type, with the worst-performing circuit named in a summary panel at the foot of the page.
Export either circuit table to CSV for your technical file, or print the whole worksheet to PDF as a record of the assessment.
Drop is calculated as k · I · L / S, where L is the full out-and-back conductor path, I the load current, S the conductor cross-section and k the copper constant, editable and set by default to 0.0164 Ω·mm²/m.
Percentage is the drop measured against the nominal system voltage. Minimum section is the smallest listed size that holds the circuit inside its target, selected from 0.75 / 1 / 1.5 / 2.5 / 4 / 6 / 10 / 16 / 25 / 35 / 50 / 70 / 95 / 120 / 150 mm².
Default limits are 10 percent for general circuits and 3 percent for critical circuits. Both are editable so the tool can be set to whatever your specification calls for.
Voltage drop is only half of conductor sizing. A conductor that passes here can still be undersized once allowable current, insulation temperature rating, engine-space conditions and bundling derating are applied. The governing constraint is whichever of the two demands the larger section.
Run every circuit through the Electrical Calculator under Tools on www.ceinspector.com as well, and fit the larger of the two results.
Blue Peter Marine provides CE certification, marine surveying and technical file compilation for recreational craft, working with IMCI as notified body. Get in touch to discuss your project.