A technical site BOM: electrical components, sensors and cable entries

Start with functional groups

A BOM is a coordinated list of components, quantities and ordering parameters. For a technical site, a useful BOM does more than list electrical devices, sensors and cables in sequence: it identifies their functions and how they connect. This makes it easier to select the required products and identify missing related items before ordering.

First separate power and switching, earthing and protection, monitoring, cable entries, cable routes and installation hardware. Each line should include a location or equipment reference, manufacturer, full code, quantity, unit and required documentation. Where substitution is allowed, list the parameters that establish compatibility.

C25 and a brand are not a full ordering code

A short electrical device description may not identify the product unambiguously. For example, a line reading 'Siemens C25' does not establish the complete series, pole count, breaking capacity or accessories. Use the manufacturer's full article number, a label photograph or a datasheet to define the required configuration.

If an auxiliary contact, release or relay socket is required, give it a separate code and link it to the main device. An accessory that looks suitable still needs a compatibility check for the selected series. The same applies to cable lugs: do not fill in ambiguous cross-sections, hole diameters or units by guesswork.

A component example: sensor and connection

A line reading 'door sensor' is a starting point for procurement. A complete request identifies the door, sensing principle, power if required, output type and monitoring system input. It then adds the suitable cable, terminals or connector, fixings and cabinet cable entry. A passive contact and a powered sensor do not have the same requirements.

Apply the same check to a temperature sensor, beacon or fire detector. Supplying the component does not define the scope of its integration into a monitoring or fire alarm system. Where wiring, configuration and functional testing are required, include them as separate work items and acceptance criteria.

The illustrative BOM below shows how to link quantities with documents and questions to resolve. B-01 and B-02 identify the same items in both tables.

Codes, documents and open questions in the example

A row identifier does not replace a manufacturer’s part number. If the exact model is unknown, state that and record the missing selection information. Keeping the code, document and question tied to the same item makes it easier to carry the technical decision back into the quantity schedule.

Select the cable entry and cable together

A cable entry such as Roxtec C ComShelt needs more than a model name: specify cable count and outer diameters, the opening, mounting surface and required sealing conditions. The product's protection rating depends on the manufacturer's assembly and installation conditions. Ratings from different Roxtec families cannot be transferred to one another or to an entire site.

For data cable, request the exact standard and category. If an input list says 'CAT6e UTP', do not automatically order it as Cat6A: Fluke Networks distinguishes these labels. Confirm the category using the datasheet, jacket marking and required link test; do not promise a transmission rate from the name alone.

Complete the list before sending the request

Run the final check by functional group, following each main device through its wiring, power, sealing and fixing items. Remove double counting where an item is already included in a kit; add a separate line where it is not. An installation drawing and label photographs help assess the suitability of a replacement.

• Quantity, unit and required delivery timing for each line.
• Full code or datasheet, label photograph and key compatibility parameters.
• Substitution permission, included parts and separately required services.
• Required certificates, acceptance documents and functional verification procedure.