Off-highway wiring harness design
Construction, agricultural and heavy-plant wiring harness design — built for harsh environments, IP-rated sealing and the ISO 14982 EMC bar.
Off-highway is where harness design meets actual weather. Construction equipment, agricultural machinery, mining trucks, materials handlers — all spending their working life vibrating in mud and water at temperatures the average passenger car would never see. The design rules are different. The sealing classes go up. The connectors are bigger. The EMC bar (ISO 14982) is its own world. The service intervals are measured in thousands of hours.
Signal Red designs harnesses for off-highway integrators — UK-based, working in the same procurement language as JCB-class buyers, but small enough to take on a single-machine prototype as cleanly as a multi-variant production programme. Build-partner neutral, design-only, the same workflow we run for automotive.
Off-Highway harness design — deliverables
Production-ready designs, costed, scoped and signed off — packaged for your build partner.
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IP-rated sealing
Connector and entry sealing designed to your IP target — IP6K9K when you need it. Drainage paths, drip loops, service caps.
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ISO 14982 EMC aware
Shielding strategy, return paths and routing rules drafted with the agricultural-EMC standard in mind from the first pass.
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Harsh-environment routing
3D routing against the machine CAD with vibration nodes, heat sources and articulation points designed around — not patched.
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Lifecycle thinking
Service access, repair-in-the-field considerations and over-mould vs glanded entries decided at design, not in production.
From brief to handover
- 01
Machine brief
Machine class, build environment, IP target, EMC target, electric / hybrid / diesel scope. One call, machine CAD if you have it.
- 02
Harness scope
Harness count, zone split, connector shortlist, sealing strategy. Costed plan and schedule back inside two working days.
- 03
Design iteration
3D routing → schematic → BOM, weekly iteration. Articulation, hinge points and service hatches reviewed at each step.
- 04
Handover
Build pack in your manufacturer's preferred format. Shakedown and first-build support included.
Off-highway is not just automotive with bigger wires
The connector lists are different. The sealing classes are different. The EMC environment is different — agricultural machines sit next to GPS antennae and radio-controlled implements, so the EMC bar is its own discipline. Service life is measured in thousands of hours of vibration, not the duty cycle of a passenger car.
We treat off-highway as its own sector for that reason. The workflow is the same as our automotive workflow — schematic, 3D routing, BOM, spec — but the design rules and the connector libraries are off-highway-specific from the first pass, not adapted from a passenger-car template.
Common questions
What IP rating can you design to?
Up to IP6K9K for high-pressure, high-temperature washdown environments. Most off-highway programmes settle at IP67 or IP69K for body harnesses; we design to whatever your machine certification needs.
Do you cover electric and hybrid off-highway?
Yes. Electrified construction plant and agricultural machinery use the same HV harness disciplines as road EV, plus extra sealing and harsh-environment constraints. See our EV & battery harness service.
What about ISO 14982 EMC?
We design with it in mind from the first routing pass — shielding, return paths, segregation from radio-sensitive electronics. Compliance testing itself is your homologation lab's job; we make sure the harness is built to pass.
Are you set up for low-volume off-highway production?
Yes. Off-highway runs are often in the hundreds rather than the hundreds-of-thousands — our workflow suits short-run production with manual or semi-automated build, not just prototype work.
Need off-highway harness design?
Send us your scope. We'll come back with a costed plan and a delivery timeline within two working days.