# Getting started

Source: https://meptools.com/tools/voltage-drop-cable-checker/docs/getting-started/

Open **Voltage Drop & Cable Size Checker** from the [tools catalog](/docs/tools-catalog). No
sign-in is needed to calculate — you only need an account to save projects or export a PDF
report.

The page is a single column: three input stages (**01 Circuit & load**, **02 Cable
selection**, **03 Installation corrections**) with the result panel beneath them. **The tool opens blank** — nothing is
pre-filled, and nothing calculates automatically as you type. You fill in the stages (or
load the worked example below), then press **Calculate**.

## Before you calculate

With no result yet, the result panel shows a start zone:

> **Your result appears here**
>
> A pass/fail verdict, the smallest size that works, a size-by-size comparison and every
> formula step — produced from the inputs below when you press Calculate.
>
> 1. Enter the circuit 2. Calculate 3. Save it — free account
>
> **Load a worked example**
> Fills a typical 400 V submain and runs it. Nothing is saved until you say so.

## Load the worked example

Press **Load a worked example** to fill both stages with a preset circuit and run it
immediately — you don't press Calculate separately; loading the example calculates it.

**01 Circuit & load**

| Field                    | Value                          |
| ------------------------ | ------------------------------ |
| Circuit type             | 3-ph AC                        |
| Nominal voltage          | 400 V                          |
| Voltage-drop limit       | Custom / project specification |
| Custom limit             | 5 %                            |
| Protective device type   | MCB - BS EN 60898              |
| Protective device rating | 80 A                           |
| Load                     | 45 kW                          |
| Power factor (lagging)   | 0.85                           |
| Parallel runs            | 1                              |
| Run length               | 65 m                           |

**02 Cable selection**

| Field                 | Value                                                   |
| --------------------- | ------------------------------------------------------- |
| Cable construction    | 4E4 (multicore XLPE armoured)                           |
| Installation method   | Clipped direct, reference method C                      |
| Circuit arrangement   | 3ph                                                     |
| Cable size            | 35 mm²                                                  |
| Ambient temperature   | 30 °C                                                   |
| Grouping              | 1 circuit                                               |
| Thermal insulation    | Not in insulation                                       |
| Manufacturer override | Off — the tabulated BS voltage-drop coefficient is used |

Once it loads, the action rail shows **Calculated** and an **EXAMPLE** badge appears next to
the **Result** heading — this is a real, already-run calculation, not a placeholder.

![Voltage Drop & Cable Size Checker showing the worked example's calculated result](./_assets/default-load-result.png)

## Reading the result

For the worked example above, the result panel shows:

- **Voltage drop 1.30 %**, badge **PASSES** — 5.21 V drop, receiving end 394.79 V.
- Three checks, all **PASS**: **Device coordination** (76.41 A ≤ 80.00 A), **Current
  capacity** (80.00 A ≤ 154.00 A), **Voltage drop** (1.30 % ≤ 5.00 %).
- Four metric tiles: **Design current / run** 76.41 A, **Corrected Iz / run** 154.00 A,
  **Coefficient** 1.049 mV/A/m, **Max length** 249.60 m.
- A recommendation: "35 mm² also passes — you are 2 sizes oversized. It gives 1.30 % against
  your 5 % limit."
- A **Length headroom** bar (65 m of 249.60 m max — 26 % used) and a **Size ladder** of
  clickable size chips — picking one recalculates the whole result against that size.
- **Cable size comparison** — "17 sizes evaluated · smallest suitable 16 mm²", with
  per-row statuses (AMPACITY FAIL, SMALLEST OK, SELECTED, PASS, and so on) and a
  **Show all 17 compatible sizes** button that reveals every row.

  ![Cable size comparison table expanded to show every compatible size](./_assets/cable-size-comparison-expanded.png)

- **Calculation steps** — an "11 steps" audit trail, with a **Summary** / **Full audit
  trail** toggle.
- **Assumptions and warnings** — a collapsible panel of any run-specific notes plus the
  standing disclaimers.
- A **Report** section offering **Print / Save as PDF** and **Export branded PDF** (the
  latter carries a **PRO** badge on free accounts).

## Editing after a calculation

Change any input once a result is showing, and the action rail switches from **Calculated**
to **Recalculate** — the figures on screen do not update yet. A strip above the result reads
"Inputs changed. You're looking at **the previous run**." until you press **Recalculate**.

## Then

- [Circuit & load inputs](/tools/voltage-drop-cable-checker/docs/circuit-and-load) — every
  field in stage 01, in detail.
- [Cable & installation selection](/tools/voltage-drop-cable-checker/docs/cable-and-installation) —
  cable families, installation methods, and the manufacturer override.
- [Correction factors](/tools/voltage-drop-cable-checker/docs/correction-factors) — how the
  installation corrections adjust the tabulated current capacity.
- [Reading the results](/tools/voltage-drop-cable-checker/docs/results) — the result panel,
  the comparison table, and the formula audit in full.
- [Exporting and saving](/tools/voltage-drop-cable-checker/docs/exporting-and-saving) — PDF
  export and project save/load.