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When quoting a panel, the switchgear is listed easily; the forgotten items are always in the details. On site, shortfalls such as "we ran out of trunking", "there are no markers", "the earth bar did not arrive" cost more in labour and time than in material. The list below groups the items found in a typical low-voltage distribution panel.
1. Body and mechanical
- Sheet steel enclosure — dimensions, IP rating and IK (impact) class are settled.
- Mounting plate — may not come with the body and should be asked for as a separate line.
- Plinth — for floor-standing panels, to set the cable entry height.
- Door locks and hinges — on wide doors the number of latches decides gasket pressure.
- Ventilation grille or blanking plate — unused openings must be closed.
2. Switchgear and protection
- Main switch or moulded case circuit breaker — with breaking capacity calculated.
- Outgoing MCBs — with rating and trip curve (B/C/D).
- RCDs — 30 mA for personal protection, 300 mA for fire; type S upstream.
- Contactors and motor protection switches — where there are motor feeders.
- Surge protection (SPD) — at the incomer, especially on exposed or rural supplies.
- Phase protection relay — on loads sensitive to phase loss and sequence.
3. Busbar and distribution
- Copper busbar and insulators — on main distribution; sized to the current.
- Comb busbar — to feed a row of MCBs, matched to the pole count.
- Neutral bar — must be separate from the earth bar after the separation point.
- Earth bar — screw type, with enough points for body and door bonds.
- Busbar supports and connection hardware.
4. Wiring and connection
- Slotted trunking — sized so fill stays under 60%, with its lid.
- DIN rail — for terminal and device rows, with length to spare.
- Terminal blocks — screw, spring or push-in; size limit set by the largest cable landing.
- Terminal jumpers and end covers.
- NYAF wire — for in-panel wiring, by size and colour code.
- Ferrules — at every point where stranded wire lands.
- Cable glands and blanking plugs — to hold the IP rating at panel entries.
5. Climate control
- Fan and filter, or a cooling unit — according to the panel heat load calculation.
- Thermostat — to switch the fan or cooler; a hygrostat is added in humid environments.
- Heater — outdoors and where panels cool overnight, to prevent condensation.
- Internal light and door switch — makes maintenance easier.
- Socket outlet — for a laptop and hand tools during commissioning and maintenance.
6. Marking and documentation
- Heat-shrink or clip-on wire markers — the terminal number at both ends of every wire.
- Terminal and device labels.
- Warning labels — external supply, voltage level, circuits not isolated by the main switch.
- Panel label — panel name, source of supply, build date.
- Single-line and layout drawings, terminal schedule — in the document pocket inside the panel.
Send your single-line diagram or a photo of the existing panel; we will draw up the bill of materials under these headings and quote the same business day. However many lines the list has, it ships on one delivery note, and can be split to your site programme if needed.
Frequently asked questions
How is the enclosure size decided?
Add the total rail width of the devices, the trunking allowance and the terminal row, then add at least 20% spare for maintenance and future additions. Depth follows the deepest device (usually a moulded case breaker or a drive) and anything mounted on the door. In height, do not forget the cable entry zone and the busbar area.
How is the panel heat load calculated?
Add up the catalogue power loss (W) of every device inside. Drives, power supplies and transformers make up most of it; switchgear contributes relatively little. The total is then assessed against the enclosure surface area and ambient temperature to decide between a fan and a cooling unit.
Off-the-shelf panel or a purpose-built one?
For standard distribution needs, an off-the-shelf body plus assembly is faster and cheaper. Purpose-built is chosen where space is constrained, where many door-mounted devices are needed, or where a special cable entry arrangement or compartmentalised structure is wanted. The decision usually becomes clear once the layout is drawn.
Do you build panels too, or only supply the material?
Both. If you take the material and build it yourself, we draw up the list with brand alternatives. If you want it turnkey, we run it from single-line diagram to commissioning, and hand over single-line and layout drawings, the terminal schedule, test records and the as-built file.