Cable Tool

Start here

Cable Tool is a deterministic patch-lead length calculator with a full floor plan editor, rack builder, BOM generator, and patching assigner built in. This page covers every part of the current build.

Choose your workflow

Two calculator pages share the same layout engine but differ in their source endpoint.

Quickstart

If you only read one section, read this.

Core concepts

Cabinet layout

Shared by all calculators, the Floor Plan, and the Rack Builder.

Trays

Trays are named overhead routes. Add them in the Trays section and they appear as options in "Routing Path" selectors. When using the Floor Plan, tray lengths are measured geometrically and written back to the tray list automatically.

• Each tray has a Name and a Length (derived from the floorplan or entered manually).
• Pick a tray per-run in Manual, per-batch in Bulk, or globally in the Assigner.
• Tray height (floor to tray) is set in Floor Plan settings and drives the "up and back down" component of tray routes.

Switch configuration

Switch config drives port grid creation and validation everywhere in the tool.

Rack Builder NEW

A physical device inventory for each cabinet. The Rack Builder is the source of truth for what is physically installed — switches, patch panels, cable managers, blanks, and custom devices.

Adding items

For each cabinet, use the Rack Builder to add items at their correct U positions. Each item has:

• Type — switch, patch panel, cable manager, blank, device, or custom
• Start U — the U position it occupies (from top)
• Height (U) — how many rack units it takes up
• Template / preset — select from built-in presets (e.g. 24-port 1U patch panel, 48-port 1U switch) or define custom
• Instance name — the label used in output schedules
• Port count / zeroBased — for switch and patch panel items

Device presets

The tool ships with presets under assets/presets/devices/. These include common 1U patch panels and switches (24-port, GPU servers, etc.). Custom presets can be added to the same folder and become available via the template picker.

Device library

Define reusable device templates for the Device → Switch (DC) workflow. This is separate from the Rack Builder — it's a template catalogue rather than a physical placement.

Project / Config

Name the configuration, manage quick saves, and export/import JSON snapshots.

• Config Name — used in export file names and displayed in the header.
• Quick Saves — store and recall up to several named configurations in the browser. Use before changing counts (cabinets, blades, ports) to avoid losing in-progress work.
• Export JSON — full state snapshot for versioning or sharing with a colleague.
• Import JSON — load a previously exported configuration. Also accessible via the file input at the top of the project panel.

Assumptions & constants

Applied globally to all route calculations. Change these to standardise across a project — not per-job.

Manual Input

Interactive mode for one-offs, spot-checks, and visual route validation.

Connection parameters

Entry-side selector

The switch has a configurable entry side (left / right / centre). This adds an offset to horizontal travel. Pick the side that matches how the switch is physically cabled in your design.

Port selection grids

Clickable grids eliminate manual port entry and drive the visual route instantly.

Visual route

A live SVG diagram of the calculated cable path. Use it to sense-check routing and explain results to others.

• Immediately updates when any input changes.
• Displays route type (internal vs tray), cabinet crossing points, and the component lengths.
• Catches wrong cabinet selections quickly — the visual makes cross-cabinet routing obvious.
• In the Floor Plan, the last-calculated route is also overlaid on the canvas in colour (green = floor plan route, amber = tray, cyan = centre).

Bulk Input

Paste many runs at once — ideal for schedule generation and importing from spreadsheets.

Bulk workflow

1. Select Input Format (see formats below).
2. Paste rows into the bulk input textarea.
3. Set Routing Path (bulk) and tray (if used).
4. Click Generate and review any validation warnings.
5. Copy or export the cable list.

Bulk add-ons (extra calculators)

The Bulk section includes routing-toggle helpers for specific connection types:

A rack-count input drives derived cable count tables — useful for modelling a hall before the full assigner is populated.

Patching Assigner

Fast range-to-range assignment with patterns. Use when the schedule is systematic.

Floor Plan FLOOR PLAN

An interactive canvas for physically laying out cabinets, drawing cable trays, importing a building plan as a PDF overlay, and deriving accurate cabinet gap distances for the calculator.

Tools & modes FLOOR PLAN

Select tools from the toolbar at the top of the Floor Plan panel:

Zoom & pan

• Scroll wheel to zoom in/out (centred on cursor).
• Click + drag in Pan mode, or hold Space and drag in any mode.
• The grid scales automatically with zoom level.

Placing & configuring cabinets FLOOR PLAN

Cabinets placed in the Floor Plan are linked to the cabinet list in the main configurator by name. The workflow is:

1. Ensure the main configurator has the correct number of cabinets defined (and named).
2. Switch to Place Cabinet tool and click positions on the canvas. Cabinets appear as labelled rectangles (23.75″ wide, 60 cm deep at default scale).
3. Drag cabinets to fine-tune positions. Gap handles appear between adjacent cabinets — drag them to adjust spacing in 5 cm increments.
4. Click a cabinet to see its config (name, U height, assigned rack config).

Row detection

The Floor Plan groups cabinets into rows automatically using a Y-position threshold (~0.8 m). Cabinets within 0.8 m of each other vertically are considered the same row, sorted left-to-right within each row. This drives the linear ordering used when syncing gaps back to the calculator.

Gap handles & spacing mode

In Spacing Mode, interactive handles appear between adjacent cabinets. Drag a handle horizontally (or vertically for same-column gaps) to adjust the centre-to-centre gap. The gap label updates in real time. Snap resolution is 5 cm.

Reference walls

A left reference wall (vertical line) and top reference wall (horizontal line) can be placed to measure cabinet-to-wall distances. Gap handles also appear between the wall and the first cabinet in each row/column.

Drawing cable trays FLOOR PLAN

Cable trays are drawn as polylines at a configurable height above the floor (the tray height setting). Each tray segment is labelled with its total length.

1. Select Draw Tray tool.
2. Click to place waypoints along the tray route. You'll see a preview line tracking the cursor.
3. Hover near an existing tray endpoint to snap to it (junction dots indicate connection).
4. Double-click or click a snapped close-point to finish the tray. The tray is named automatically and its length is calculated from the polyline.

Tray colours

Each tray path has a configurable colour (defaults to purple). Hidden trays render grey and non-interactive — useful when you need to draw a new tray on top of existing ones. Toggle Hide Trays in settings to enter overlay drawing mode.

Tray height & slack

• Tray height from floor (m) — the physical height of the cable tray. Adds a "rise + return" component to every tray-routed cable.
• Tray slack (cm) — additional allowance for bends, corners, and dressing. Added to tray-routed cable lengths on top of route slack.

Drop lines (cabinet-to-tray connections)

Use the Connect tool to draw a connection from a cabinet attachment point to a tray. This models the vertical drop from tray height down to the cabinet. Drop lines are shown as dashed lines on the canvas.

Scale calibration FLOOR PLAN

Before measurements mean anything, you need to calibrate the scale — especially important when working with a PDF background overlay.

1. Select Scale Calibrate tool (or click the calibrate button in settings).
2. Click the first known point on the canvas (e.g. one end of a scale bar on your floor plan).
3. Click the second known point.
4. Enter the real-world distance between those points in the prompt.
5. The tool calculates pixelsPerMetre and applies it globally.

The grid display updates to reflect the new scale — each cell shows its real-world size (metres or inches, matching the global unit setting).

PDF background overlay FLOOR PLAN NEW

Import a building floor plan, CAD export, or architect's drawing as a PDF and overlay it on the canvas to trace cabinet positions and tray routes accurately.

Importing a PDF

1. In the Floor Plan settings panel, click Choose PDF / Image file.
2. Select a PDF or image file from your computer. The file is rendered using PDF.js (up to 2048 px on the longest dimension).
3. The overlay appears on the canvas. Use the controls to adjust its position, scale, rotation, and opacity.

Overlay controls

Workflow: trace from a floor plan

1. Import the PDF and set opacity to ~0.45.
2. Use Scale Calibrate against a known dimension on the plan (scale bar, grid, room dimension).
3. Resize and position the PDF overlay to match. Enable Edit Mode and drag the overlay to align it.
4. Switch to Place Cabinet and click to position cabinets on top of the floor plan room/hall markers.
5. Draw trays along the cable tray routes shown on the plan.
6. Apply the layout back to the project.

Syncing floor plan to project FLOOR PLAN

The Floor Plan and the main calculator are linked. Sync happens in two directions:

Row ordering and gap logic

When applying to the project, cabinets are ordered by their floor plan position (top-to-bottom rows, left-to-right within each row). The gap written for each cabinet is the centre-to-centre distance to the next cabinet in this linear sequence. Cross-row transitions use a configurable row gap.

SU Configurator (Scalable Units) FLOOR PLAN NEW

An SU (Scalable Unit) is a predefined cabinet group that repeats as a unit — for example, a standard 4-cabinet compute row with a fixed rack config. SUs let you deploy a repeating layout across multiple rows without re-configuring each row manually.

Creating an SU template

1. In the SU Configurator panel, click New SU Template.
2. Name the template and define its slots — each slot is a cabinet with an assigned rack config (from the rack configs list).
3. Set the rows this SU applies to. Rows can be specified as a list (A, B, C) or a range (A-F).

Deploying an SU

1. Select a template and click Deploy.
2. The tool checks which target rows already exist in the floor plan.
3. For each target row, cabinets are placed (or matched by name) and assigned the rack config from the corresponding SU slot.
4. Existing cabinets in the row are overwritten with the SU layout.

Rack configs

Rack configs (used within SU slots) define a named cabinet configuration — switch type, patch panel layout, cable management — that can be applied to any cabinet in the floor plan. Edit rack configs in the Rack Configs section of the Floor Plan settings.

Power Load Letter NEW

A server room capacity planning tool that models device power consumption per rack, calculates IT and facility loads, and exports a professional PDF load letter for client delivery or M&E design.

Access it via the Calculator dropdown at the top of the tool — select Server Room Load Letter.

Projects

Each engagement is a project. A project stores the client name, site name, racks, and all rack items. You can have multiple projects and switch between them. Projects are saved server-side and persist across sessions.

• New project — creates a blank project with a name you choose
• Export project — downloads the full project as a JSON file for backup or sharing
• Import project — restores a previously exported JSON
• Delete project — removes all racks and items permanently

Device library LOAD LETTER

The device library is a shared catalogue of hardware with known power figures. Each device entry contains:

Search the device library by vendor or model name. Select a device to add it to a rack — quantity and U position can be set at the time of adding.

Building racks LOAD LETTER

Within a project, add as many racks as the design requires. Each rack is named and holds an ordered list of devices.

• Devices are displayed top-to-bottom matching the physical rack layout (highest U at top).
• Each rack shows its typical kW, max kW, and RU used pulled from the report cache.
• Items can be repositioned by U, have their quantity changed, or be deleted individually.
• The rack view updates totals live as items are added or removed.

Summary & report LOAD LETTER

The summary panel shows the rolled-up power and cooling figures for the entire project across all racks:

Both Typical and Max figures are shown side by side — typical for operational planning, max for circuit sizing and worst-case design. The rack count is also summarised.

PDF export LOAD LETTER

Clicking Generate PDF produces a formatted A4 load letter suitable for client delivery or inclusion in an M&E design pack. The PDF includes:

• Project name, client name, and site name in the header
• Your company logo (upload via the logo uploader in the tool — stored in browser localStorage)
• A summary table of typical vs max IT load, facility load, cooling (BTU/hr and tons)
• A per-rack breakdown showing device list, RU usage, and typical/max kW per rack
• Date stamp

Logo upload

Upload a company logo via the logo uploader in the Load Letter settings. The logo is stored in browser localStorage and applied to all PDFs generated from that browser. To use a default branding logo server-side, place it in assets/branding/ — the tool will fall back to it if no user logo is uploaded.

BOM / Materials Tool NEW

Generate structured bills of materials for cabling projects across floors and infrastructure types. The BOM tool is separate from the cable-length calculator but shares the same project state.

The BOM tool has four tabs:

Cable Count tab

Tracks cable consumption per floor and infrastructure type. You define:

• Floors — add one per project floor or zone
• Infrastructure types — e.g. Cat6A outlets, Cat6A patch panels, fibre backbone
• Cable count per floor × infra combination — enter outlet counts; cable per outlet is calculated from run assumptions

Total cable quantities are summed at the bottom. Results are ready for export or copy-paste into a procurement sheet.

Materials BOM tab

Generates a full bill of materials per floor and infrastructure type using the brand catalog. For each infrastructure entry, the BOM produces:

• Cabling (cable reel quantities, jack quantities)
• Outlets (surface mount boxes, faceplates — 1/2/4/6 port)
• Patch panels (24/48 port, straight or angled, Cat6 or Cat6A)
• Infrastructure items (cable management, racks, fibre enclosures)
• Power items (UPS, PDU, ATS)

Supported brands

Brand can be set per-infrastructure type. Part numbers and descriptions pull from the catalog automatically. Catalog entries with no part number show as blank (editable in the Catalog tab).

Currency

A currency selector at the top of the BOM tool controls the symbol used in any price columns. Currently supports GBP, USD, EUR.

Patch Leads tab

A dedicated section for modelling patch lead quantities — typically the output of the cable length calculator fed back into a BOM context. Enter quantities per length band (0.5m, 1m, 1.5m, 2m, 3m, 5m) and the tool summarises totals by colour/type for ordering.

Catalog tab

View and edit the full product catalog inline. Each row shows:

• Brand, category, part number, and description
• A quick search link (opens manufacturer/distributor search in a new tab)
• Editable fields — changes apply for the current session and are saved to project JSON on export

The catalog also supports plex variants (simplex / duplex for fibre, single/two-gang for outlets) and cat spec variants (Cat6 vs Cat6A per infrastructure type).

Saving & exporting

Troubleshooting

FAQ

Do I need to use the Floor Plan?

No — you can enter cabinet gaps manually in the cabinet table and skip the floor plan entirely. The Floor Plan is most useful when you have a building plan to work from, or when cabinets are arranged in multiple rows with varying gaps.

Do I need trays?

No — internal routing works without trays. Trays matter when you want the model to include overhead travel: up to the tray, along the tray run, and back down.

Why is there a "ports start at 0" option?

Some designs label switch ports 0–47 instead of 1–48. The toggle makes the UI labels match your real-world port labels to prevent off-by-one mistakes in output schedules.

Is DC the same as DCIM?

DC refers to the Device → Switch calculator page.

What's the difference between Rack Builder and Device Library?

The Rack Builder is a physical placement registry — it records what is installed at which U position in which cabinet. The Device Library is a template catalogue for the DC page — it defines device types (name, port count, U height) that you select when picking a source device on the Device → Switch calculator.

Can I import an existing patching schedule?

Yes — the Excel Import feature in the Patching Assigner reads an XLSX with switch port maps, identifies occupied ports, and populates free port ranges by VLAN/service into the Switch Port Map. This requires the API container to be running if self-hosting.

Can the tool do full rack placement?

The Rack Builder handles physical device placement at U positions. Full "per-port geometry from rack placement" is the direction this is heading — the Device Library + DC workflow and the Rack Builder lay the groundwork.

How do I self-host?

The repo includes Docker files under docker/. The main app is a static site served via nginx. The BOM and Excel features use an optional API container (Node.js) and a PostgreSQL database — see docker/docker-compose.snippet.yml and bom/api/ for configuration. The bom/db/init/ folder contains schema and seed SQL.

What units does the Floor Plan work in?

Internally all floor plan distances use metres. Cabinet gaps and tray slack are kept in centimetres to match the main calculator state. All UI labels follow the global length unit toggle (cm / inches). When you switch units the Floor Plan re-converts all visible inputs automatically without changing the underlying world values.

Contact

For bugs, feature requests, or questions, reach out to my self directly here .