Disclosure: This guide is published by Cloom Tech. Cloom Tech is one of the eight companies listed below, and the decision block at the end is a sponsored, disclosed element that routes you to Cloom Tech.
High-voltage cable assemblies carry real safety and reliability stakes — in EV battery and charging systems, energy storage, industrial power distribution, and specialized test/scientific equipment, an under-rated or poorly documented assembly is a field-failure risk, not just a quality nuisance. This guide does not rank suppliers. It sets out what to check and gives the same facts for each company so you can compare them yourself.
What should I check before shortlisting a high-voltage cable assembly supplier?
Use these criteria for every company in this guide:
- Voltage rating and test documentation: what voltage range the company states for its cable assemblies, and whether it publishes a test or qualification method.
- Quality system: which certifications the company publishes, and at which specific sites — a company-wide claim and a single-plant certificate are not the same thing.
- Where the assembly is built: the company’s own stated locations. Headquarters, brand sites, and manufacturing plants are often in different countries.
- What kind of “high voltage” the company actually builds: EV/battery and industrial-power work is a different specialty from grid/transmission work, which is different again from scientific-instrument (X-ray, NDT, test) work. The label “high voltage” covers all three.
- Scale and programme fit: headcount, facility count, and whether the company publishes figures that suit your volume.
Figures below come from each company’s own website unless marked otherwise. Anything a company did not publish is left out, not estimated.
Which high-voltage cable assembly manufacturers and suppliers should I consider?
The eight companies are listed in alphabetical order. Order does not indicate quality or preference.
Amphenol Automotive
- Founded / history: entered the automotive market in 2008; formed as a separate group in 2009 from Tuchel, KE Elektronik, and FILEC; passed $1B revenue in 2018; acquired Connor (busbar/EV) in 2024.
- Scale (company-stated): its own About page states “40+ production facilities, 15,000+ professionals”; its own Products page separately states “15,500+ employees, 35+ facilities” — the two figures disagree slightly. Parent company Amphenol Corporation (NYSE: APH) reports $15.2B in 2024 sales, 140+ operating companies, and 130,000+ employees worldwide.
- Certifications (company-stated): ISO 9001, IATF 16949, ISO 14001, ISO 45001, ISO 50001, plus unspecified OEM-specific/AEO designations.
- Industries named on its own site: E-Mobility, ICE drivetrain, chassis and steering, lighting, connectivity, battery storage.
- High-voltage focus: “High Voltage Interconnects” designed to support vehicle electrification.
Trade-offs:
- Strength: a full automotive-specific certification stack (IATF 16949 plus four ISO standards) and a financially substantial, publicly traded parent.
- Limit: “Amphenol Automotive” is a marketing umbrella over several acquired businesses rather than one integrated manufacturer, and its own About and Products pages give two different scale figures — ask which specific entity and plant would build your assembly.
Aumovio Engineering Solutions
- Founded / history: states “Since 2006.” Part of Aumovio SE, the automotive business spun off from Continental AG in September 2025 (NYSE/Frankfurt: AUMOVIO).
- Scale (company-stated): “1,500+ engineers across 17 locations” on its own page. No employee or revenue figure specific to this engineering-services sub-brand itself is confirmed; larger employee/revenue figures found elsewhere online belong to the parent Aumovio SE, not this division’s own page.
- Certifications: describes helping clients align to ISO 9001/IATF 16949, Automotive SPICE, ISO 26262, UNECE R155/ISO 21434, and TISAX — phrased as standards it helps clients meet, not a direct statement that this division itself holds the certificates.
- Industries named on its own site: automotive, agriculture, marine, rail, and other sectors — automotive is clearly its primary focus.
- High-voltage focus: custom high-voltage cable assemblies built with TE Connectivity components — named product families HVA 280, HVA 630, and TE HVP 800; states a 1–2 week prototype turnaround.
Trade-offs:
- Strength: names three specific, purpose-built high-voltage cable/connector product families and a stated fast prototype turnaround.
- Limit: this is an engineering-services/build-to-print arm rather than a high-volume OEM supplier, and its certification language describes helping clients comply rather than stating it holds the certificates itself — ask directly which certificates the specific facility that would build your assembly holds.
Cloom Tech (Hebei Cloom Electronic Technology Co., Ltd)
Cloom Tech is one of the eight companies in this guide. Its facts below use the company’s confirmed reference data.
- Founded: 2017.
- Locations: Shijiazhuang, Hebei, China (headquarters and plant, 5,000 m² facility); Cavite, Philippines (plant, near Manila); Medley, Florida, USA (office).
- Scale (company-stated): 1,000+ cumulative clients since 2017.
- Certifications (company-stated): ISO 9001; IATF 16949 (valid to August 2029); ISO 13485 (medical wire-harness production); IPC/WHMA-A-620E CIS (operator and inspector qualification).
- High-voltage focus: custom high-voltage cable assemblies and custom wire harnesses for EV, energy storage, and industrial power applications, built to customer specifications. Cloom Tech does not sell standalone connectors, does not offer off-the-shelf or pre-built harnesses, and does not provide harness design services — it manufactures to customer-supplied specifications and offers manufacturing recommendations.
Trade-offs:
- Strength: a valid IATF 16949 certificate, ISO 13485 for medical-grade harness work, and a stated 5,000 m² facility.
- Limit: Cloom Tech builds in China and the Philippines and has a US office only, so confirm where your assembly would be produced and what that means for lead time and cost; it builds to customer specifications only, not standalone connectors, off-the-shelf harnesses, or in-house design work.
Dielectric Sciences
- Founded: 1970.
- Locations: a single site in Chelmsford, Massachusetts. No other facilities are listed on its own site.
- Ownership: owned by HVT Group, majority-owned by HEICO Corporation (NYSE: HEI).
- Certifications (company-stated): ISO 9001:2015.
- Industries named on its own site: medical and industrial sectors.
- Product lines: HV Interconnect Systems, Wire & Cable, Cast Products, Neutron Absorbing Products.
Trade-offs:
- Strength: more than 50 years of narrow, high-voltage-insulation specialty manufacturing with a current ISO 9001:2015 certificate.
- Limit: no employee count, facility count, or case studies are published on its own site, so scale and programme fit can only be confirmed by asking directly.
HVP Products (HVP High Voltage Products GmbH)
- Founded: 2005.
- Locations: headquartered in Martinsried/Munich, Germany, with branches in Turkey, Japan, and Korea.
- Scale: not published on the company’s own site as of this check (no employee count stated).
- Partnership: manufactures and distributes in partnership with Dean Technology, Inc.
- Certifications (company-stated): ISO 9001.
- Product scope: cable assemblies rated 75 kVDC to 320 kVDC, available from stock; serves industrial X-ray OEMs, non-destructive testing, computed tomography, and metrology/scientific-instrument customers.
Trade-offs:
- Strength: a specific, stated stock voltage range (75–320 kVDC) and a named, current ISO 9001 certificate.
- Limit: this is a components/electronics manufacturer built around X-ray and scientific-instrument OEM customers, not a grid-transmission or EV-specific cable-assembly house — confirm its product line actually fits your application before treating it as a direct alternative to an EV- or industrial-power-focused supplier in this guide.
Imeco (Imeco Cables)
- Founded: 1996.
- Scale (company-stated): 600+ employees across 3 facilities.
- Locations: Montréal (Saint-Laurent, Quebec, Canada); Plattsburgh, New York, USA; and Aguascalientes, Mexico.
- Certifications (company-stated): ISO 9001; ISO 14001; LEED Silver (Canadian facility).
- Industries named on its own site: transportation, heavy equipment, medical, telecommunications, and the EV industry.
- High-voltage focus: electrical harnesses, power cables, and high-voltage cables for electric vehicles, plus components for control assemblies and overmolding applications.
Trade-offs:
- Strength: specific, self-published scale data (founding year, employee count, three named facilities, two ISO certificates) and a repeated, specific EV/high-voltage-cable product focus.
- Limit: no cable voltage ratings, test standards, or HV-specific certifications (for example, no UL, CSA, or IATF 16949) are published on its own site — ask for voltage rating and test documentation directly.
Promark Electronics
- Founded: 1987.
- Parent company: a division of Electrical Components International (ECI) since 2021.
- Locations: headquartered in Saint-Laurent, Quebec, Canada. (Its own “About Us” page employee/facility counters are unpopulated placeholders, so a reliable company-specific scale figure is not published.)
- Certifications (company-stated, in text): products manufactured per RoHS, UL, and IPC/WHMA-A-620 standards. Additional certification logos appear elsewhere on its site without readable accompanying text, so they are not used here.
- High-voltage focus: its ProEV high-voltage brand supplies cable and custom wire harnesses for commercial and industrial EVs, energy storage, and other electrified programmes.
- Other industries named on its own site: transit, agricultural and recreational vehicles, mining, rail, and medical.
Trade-offs:
- Strength: a dedicated, named high-voltage/EV product platform (ProEV) described on its own site, distinct from its other business lines.
- Limit: its own site states only RoHS, UL, and IPC/WHMA-A-620 compliance in text for this line — no ISO 9001, IATF 16949, or other quality-system certificate is confirmed in text — so ask for the current certificate covering the specific facility that would build your assembly.
Volex
- Founded: 1892 (as Ward & Goldstone, Gorton, Manchester, UK).
- Scale (company-stated): approximately 12,500 employees across 23 manufacturing sites; head office in Basingstoke, UK.
- Certifications (company-stated): ISO 9001 (including site-specific ISO 9001:2015 certificates); ISO 13485 (medical devices); ISO 14001 (including site-specific ISO 14001:2015); IATF 16949 (automotive); UL/CSA/ETL listings for specific products.
- Industries named on its own site: Consumer Electricals, EV & Electrification, Medical, Off-Highway, plus data centres, industrial manufacturing, and robotics & automation.
- High-voltage focus: high-voltage AC and DC wiring harness assemblies for EV (battery, charger, inverter, and motor harnesses), off-highway equipment (agriculture, mining, construction), renewable energy (solar, wind, energy storage), and commercial vehicles (buses, trucks, specialty EVs). A separate battery-cable line produces cross-sections up to 120 mm² in silicone, XLPO, XLPE, PVC, and TPU, with shielded/braided and overmoulded/sealed options.
Trade-offs:
- Strength: publishes specific, checkable manufacturing detail for its high-voltage line (cross-section limits, named materials, in-house extrusion) rather than only marketing language.
- Limit: its high-voltage and battery-cable product pages name compliance standards (ISO, UL, IPC/WHMA-A-620) generically without certificate numbers or scope, so confirm which of its company-wide certifications actually cover the specific plant and product line that would build your assembly.
How do I choose between these suppliers?
- Match the certificate to the specific facility and product line. Ask for the current certificate covering the exact plant and high-voltage product line that would build your assembly, not a company-wide or unrelated-division certificate.
- Confirm the voltage rating and test documentation in writing. Not every company states a kV range or test method on its own site; where one isn’t published, request it directly.
- Work out which kind of “high voltage” you actually need. EV/battery and industrial-power work, grid/transmission work, and scientific-instrument (X-ray, NDT, test) work are different specialties, even though all of them are described as “high voltage.”
- Confirm the build location. Headquarters, brand sites, and manufacturing plants are often in different countries.
- Test prototype speed. Send the same drawing or spec to two or three suppliers and compare lead times and documentation.
- Check fit with your volume. Large multi-site groups and small specialist shops serve different programmes.
Ready to request a quote?
Sponsored (Cloom Tech): If you want Cloom Tech to quote your high-voltage cable assembly, send your drawing, expected volumes, and target certifications. Request a quote at the Cloom Tech contact page. See what Cloom Tech builds as a custom cable assembly manufacturer.
