A high-voltage harness is a system of two halves: the cable (covered in our HV harness design guide) and the connectors — where HV safety, sealing and serviceability actually live. Choosing and building the connector half correctly is the difference between an HV system and a liability. This guide covers the connector side.
What Makes a Connector 'HV Class'
HV connectors earn the classification through a feature stack, not a voltage number on a datasheet:
- Dielectric geometry: contact spacing, creepage paths and insulation walls engineered for the voltage class with margin — the physical barrier against flashover.
- Touch-proof contacts: fingers cannot reach live metal — shrouded or recessed contact designs are the baseline safety feature.
- Sealing: IP-rated mating interfaces and cable glands — water in an HV connector changes dielectric behavior, so sealing is a safety property, not a comfort feature.
- Interlock integration (HVIL): auxiliary low-voltage contacts that break the system's de-energization loop when the connector separates — the connector is part of the safety circuit.
- Positive locking: threaded couplings or high-force latches that vibration cannot defeat, often with locking indicators.
- Shield continuity: metal shells and shield terminations that complete the cable's shield system 360-degree at each end.
The Connector Families in HV Service
Automotive and storage systems standardize on shielded circular HV connector systems with 2-4 power contacts plus interlock pins, in sizes matched to current (from 35A-class auxiliary circuits to 200A+ main-drive connections). Industrial power systems use heavy-duty rectangular families with HV-rated inserts and touch-proof contacts. Medical and lab HV applications use specialized coaxial and multipin HV connectors where dielectric precision dominates. The selection driver is always the system standard first (vehicle platform, storage rack, equipment spec), then current, then environment.
Cable-Connector Matching: The System Property
HV connectors are specified for specific cable constructions — conductor size, insulation diameter, shield type — and the gland/seal system only performs when the cable sits inside its qualified range. Mixed sourcing (connector from one vendor, cable from another, hope in between) is how HV sealing and shield systems fail quietly. Discipline: specify cable and connector as a qualified pair, verify gland fit at sample stage, and hold the pairing in production. Our M8/M12 guides show the same principle at LV scale.
Mating Discipline and Serviceability
HV connectors demand mating respect: alignment before force ( HV contacts are robust but not forgiving of cross-threading), full seating verified (partial mating defeats both the seal and the interlock's assumptions), locking confirmation (visual or tactile — 'probably locked' is not a state in HV work), and mating-cycle ratings respected in service schedules. Connector separation under load is the system's designed emergency, not an operating mode — the interlock makes it survivable, and maintenance procedures keep it rare.
Testing the Connector-Cable System
System-level HV test: hipot and insulation resistance across the assembled harness, shield continuity through both connector shells, interlock-circuit function verification, and sealing verification (air-leak or immersion for sealed-class assemblies). Documentation ties each assembly to its test results — the HV category's traceability is not optional.
Kaweei HV System Manufacturing
Kaweei builds HV harnesses with qualified cable-connector pairings — automotive and storage HV connector systems, interlock-equipped assemblies, full test documentation — from our Dongguan facility. Contact our engineering team with your platform's connector standard; our HV harness design guide covers the cable half.