Specifications for Electric Vehicle Wiring

Electric vehicles are increasing in popularity. As consumer demand continues to rise, so does the need for electric vehicle wire, cable, and other charging components.
Here, we examine the specifications for electric vehicle cable assemblies. Due to the growing nature of the industry, it's essential to recognize the difference between electric vehicle wire and components and those geared for traditional ICE (internal combustion engine) vehicles.

Overview of Hybrid & Electric Vehicle Wire Differences

In the inner workings of EVs, think of wires as the single conductors and cables as groups of wires or bundles of conductors. The wires and cables conduct the electricity that powers the vehicle's battery and keeps the vehicle running.
Generally, there are two types of electric vehicle cables that are part of the Electric Vehicle Supply Equipment (EVSE):

  • Battery Cables -  Unlike low-voltage ICE cables, are designed for higher electrical currents and voltage.
  • Charging Cables -  Used for connecting the vehicle to an outside electrical source.

Electric vehicles (EVs) are typically equipped with two different charging cables. A Type 1 charging cable is used for recharging in a three-pin socket. The Type 2 EV charging cable is used at many public charging stations and home EVSEs (EV charging stations). Popular models of EVs include the Nissan Leaf, Tesla Model S, and the BMW i3.
Hybrid electric vehicles (PHEVs) also use charging cables, but the setup is a little different. A PHEV has a traditional combustion engine powered by an electric motor. A PHEV can be charged at a public EVSE or using a portable EV charge that plugs into a standard socket. Popular PHEVs include the BMW X5e, the Volvo XC90, and the Mitsubishi Outlander.
Due to the evolving nature of the EV industry, there is a lot of technology surrounding electric vehicle wire, cables, and charging components. Many popular EVs and PHEVs have different charging levels, plug types (depending on location), AC or DC charges, and battery capacity.
Other EV charging cables and components include:

  • THHN Building wire and data cables to connect the grid to the charging station.
  • Charging station switchboard wire, data cables, and switch boxes.
  • Connectors, cord grips, and receptacles for connecting the charging station to the vehicle.
  • Primary automotive wire.
  • Standard battery cable, used in PHEVs.
  • Ethernet cables, ISO wire, and CAN bus cable.

EV Battery Cable Specifications

The power capacity is the main difference between battery cables for EVs and the traditional low-voltage cable used in ICE vehicles. Most EVs require 400 volts and beyond. Other standards and specifications can vary around the globe.
For most electric vehicle batteries, the following ranges apply:
  • Voltage: 100V-200V for PHEVs and 400V to 800V and beyond for EVs.
  • Insulation: Polyvinyl Chloride (PVC), thermoplastic polyurethane (TPU), cross-linked polyethylenes (XLPE), cross-linked fluoroelastomers (XLFE), and silicone.
  • Temperature Resistance: PVC-insulated cables are rated for 90° to 105° C; TPU-insulated cables and XLPE-insulated cables are rated up to 125° C (note: Irradiation XLPE is rated up to 150° C); XLFEs and silicone-insulated cables are rated at up to 200° C.

Insulation and temperature resistance are critical factors in avoiding electromagnetic interference and damage to the electric vehicle wires, cables, and other components. The cable must withstand the heat over the life of the vehicle. Each type of insulation has pros and cons. The popular PVC insulation is cost-effective and flexible but offers less heat protection. TPU is water-resistant but also has a lower heat rating. XLFE is strong with higher heat tolerance, but rigid and inflexible, making it difficult to use with tight tolerances. Silicone is highly flexible and heat resistant but doesn't offer resistance to certain chemicals like battery acid.
To determine the best cable selection, engineers will often refer to IEC 60287 or the "calculation of the continuous current rating of cables (100% load factor)" to understand the current carry capacity of a given EV cable. Other standards may include ISO-19642-5 Road vehicles: Automotive cables, and ISO 6722-1:2011: Road vehicles: 60 V and 600 V single-core cables.
What color are the high-voltage cables used on hybrid-electric or electric vehicles? Most cables are orange, but some are also blue. Consumers must understand how to identify these cables on their vehicles. Most OEMs are well-versed in the different colors used in cable manufacturing, but a reminder is helpful.
From a consumer perspective, charging cable requirements depend on the charging station and the vehicle's capacity. Mode/Type/Level 1 charging station standards are 120 volts, using AC. These are considered a universal charger—matching the standard North American wall socket with 15 amps.
Mode/Type/Level 2 charging stations are 240 volts, using AC. Most public charging stations are level 2, offering 40 amps, similar to the capacity of large in-home appliances.
Mode/Type/Level 3 charging stations are known as "rapid" or "superchargers" with DC. These charging stations are connected directly to the grid, with 50-400 KW of power. They require over 480 volts and 120 amps.
The levels offer various speed and charging power ranges, Level 1 being the slowest and lowest, and Level 3 being the highest with the fastest charging times.

Other Wiring Considerations for EVs

Electric vehicles and hybrids also require connectors for charging. The standard connector meets SAE J1772 for Level 1 or Level 2 charging stations.
The CHAdeMO connector is standard in Japan and is often used by Japanese manufacturers like Subaru, Nissan, and Toyota. CHAdeMo connectors require an additional J1772 connector for Level 1 and Level 2 chargers. Similarly, the Combined Charging System (CSS) is another charging standard. Unlike the CHAdeMO, the CSS allows for AC/DC charging.
Tesla vehicles have their own connector for supercharging. Tesla models also offer CSS and CHAdeMO adaptors for their vehicles, especially in countries where Tesla connectors aren’t readily available at most charging stations. 
ISO 15118 Plug and Charge capabilities are increasingly becoming standard amongst EV automakers. ISO 15118 is a V2G, or vehicle-to-grid communication interface. The V2G communication is used for charging and discharging EVs. When a vehicle with Plug and Charge technology plugs into a charging station, the station automatically detects the type of EV and makes the appropriate accommodations. The technology is available in Tesla EVs, as well as the Mustang Mach-E, Porsche Taycan, and other newer vehicles.
For all EV cables and electric vehicle wires, IEWC is a trusted source. For over 60 years, we’ve served customers with electric components and resources. Around the globe, we serve OEMs, sub-assemblers, and contract manufacturers with wire, cable, and wire management products and solutions. Reach out today to learn more.

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