[{"data":1,"prerenderedAt":113},["ShallowReactive",2],{"example-voltage-drop-en":3,"faq-voltage-drop-en":75,"sources-voltage-drop-en":109},{"input":4,"output":14},{"circuit":5,"currentA":6,"lengthOneWayM":7,"areaMm2":8,"systemVoltage":9,"conductorMaterial":10,"conductorTempC":6,"standard":11,"maxDropPercent":12,"annualOperatingHours":13,"energyPriceCtPerKwh":6},"dc",30,5,6,12,"cu","iec-60364",3,1200,{"dropVolts":15,"dropPercent":16,"powerLossWatts":17,"annualLossKwh":18,"annualLossCostCt":19,"standardLimitPercent":12,"withinUserLimit":20,"withinStandardLimit":20,"headroom":21,"userLimitPercent":12,"steps":25,"warnings":45},0.8959285649999998,7.4660713749999985,26.877856949999995,32.25342833999999,967.6028501999998,false,{"maxLengthM":22,"maxCurrentA":23,"minAreaMm2":24},2.0090887491683005,12.054532495009804,14.932142749999999,[26,32,37,41],{"label":27,"expression":28,"value":29,"unit":30,"provenance":31},"resistivity","rho_20 * (1 + alpha * (T - 20))",0.017918571299999998,"Ohm*mm^2\u002Fm","measured",{"label":33,"expression":34,"value":15,"unit":35,"provenance":36},"actualDrop","(2 * rho * L * I) \u002F A","V","exact",{"label":38,"expression":39,"value":16,"unit":40,"provenance":36},"dropPercent","dU \u002F U_nom * 100","%",{"label":42,"expression":43,"value":17,"unit":44,"provenance":36},"powerLoss","dU * I","W",[46,54,60,65,70],{"level":47,"code":48,"params":49,"anchors":51},"critical","DROP_ABOVE_STANDARD",{"actual":50,"limit":12,"standard":11},7.47,[52,53],"areaMm2","lengthOneWayM",{"level":55,"code":56,"params":57,"anchors":58},"warning","DROP_ABOVE_LIMIT",{"actual":50,"limit":12},[52,59],"maxDropPercent",{"level":61,"code":62,"params":63,"anchors":64},"info","LENGTH_INTERPRETATION",{},[53],{"level":55,"code":66,"params":67,"anchors":68},"TEMP_ASSUMED",{},[69],"conductorTempC",{"level":61,"code":71,"params":72,"anchors":73},"AMPACITY_SEPARATE_CHECK",{"required":6},[74],"currentA",[76,79,82,85,88,91,94,97,100,103,106],{"q":77,"a":78},"I already have 6 mm² cable — how do I check whether it is sufficient?","Unlike the wire-sizing calculator, the cross-section here is an input, not a result: the calculator returns the drop in volts and percent, the power loss, and a comparison against both your own limit and the applicable standard's limit. For the DC two-wire case it additionally answers the three reverse questions: maximum length, maximum current and minimum cross-section.",{"q":80,"a":81},"Why is the reactance per metre X′ a required input for AC circuits?","For AC the drop is ΔU = 2 (or √3) · I · L · (R′ · cos φ + X′ · sin φ), so the reactance term is mandatory. It is found in the cable datasheet, not in the standard, and varies by more than a factor of two depending on construction. Assuming a typical value would be exactly the kind of silent guess this engine refuses to make.",{"q":83,"a":84},"Does an acceptable voltage drop mean the cable is thermally safe?","No — this calculator checks voltage drop only. A cross-section can meet the drop limit and still be thermally impermissible; ampacity is a separate check, which the result explicitly flags. Harmonics, contact resistance at terminals and connectors, short-circuit withstand and skin effect at very large cross-sections are also outside the scope.",{"q":86,"a":87},"What distinguishes this calculator from the wire-size calculator?","The direction: the wire-size calculator recommends a size for given requirements; this one checks an EXISTING or planned run — and additionally answers the three reverse questions: how much longer may the run get at this cross-section, how much current does it carry, what cross-section would be minimal? That is the question you actually have on site with the cable drum in hand.",{"q":89,"a":90},"Why are two limits checked?","Your design limit (e.g. 3%) is a quality decision — for module-controller runs 1–2% often pays, since every point directly costs yield. The code limit is binding independently. The calculator shows both lines in the bar and warns separately: breaching your limit means inefficient, breaching the code limit means impermissible.",{"q":92,"a":93},"How much does conductor temperature distort the result?","Copper resistance rises ~0.4% per kelvin: between a 20 °C workshop measurement and 60 °C in a sun-exposed cable duct lie 16% more resistance — and thus 16% more voltage drop. The calculator corrects resistance to your conductor temperature; the 30 °C default is conservative indoors, too low for roof runs in summer.",{"q":95,"a":96},"Can the calculator also check AC circuits?","Yes — since 5 August 2026 through the interface too: single-phase (230 V) and three-phase (400 V), with power factor and reactance. The AC half previously existed only in the calculation core; the form had no switch for it. For three-phase the formula uses √3 instead of factor 2 — 16 A over 25 m in 2.5 mm² gives 1.24 %.",{"q":98,"a":99},"Where does the AC reactance come from?","From the NYY catalogue dataset for the chosen cross-section — sourced, not guessed, and named as a note. The engine itself deliberately refuses to guess it: it lives in the cable datasheet, not the standard, and varies by construction by more than a factor of two. If you have your datasheet, enter the value via the switch — it then wins.",{"q":101,"a":102},"Why does the worked example show a code violation?","Because that is exactly the calculator's question: “I have 6 mm² lying around — is that enough?” For 30 A over 5 m at 12 V the answer is no — 7.47 % against the permitted 3 %. An example that always “passes” would hide the calculator's warning side. The three reverse questions beside it show the ways out: shorter run, less current, or 16 mm².",{"q":104,"a":105},"What do the three reverse questions mean?","They solve the same equation for one variable each: how long may the run be at most? How much current does it take within the limit? What cross-section would be needed? For the DC two-wire case all three solve in closed form; in the AC case with reactance they are omitted, because the equation no longer solves for a single variable — the page says so openly.",{"q":107,"a":108},"What does the voltage drop really cost per year?","Loss power times operating hours times electricity price — both factors are adjustable since 5 August 2026. The 6 mm² example burns 27 W; at 1,000 operating hours and 31.1 ct that is about €8 a year, a continuous runner would exceed €70. Set against the extra cost of 16 mm², the thicker cable often pays for itself in the first year.",[110],{"name":111,"url":-1,"retrievedAt":112,"version":-1},"Official publications of the standards bodies and state authorities (NFPA, IEC, DKE\u002FVDE, CEN)","2026-07-15",1786101726670]