A 64/110kV high voltage cable is generally specified for a network with a rated voltage of 64 kV between conductor and earth and 110 kV between conductors; the associated highest system voltage is commonly shown as 123 kV. Its construction typically includes a conductor, semiconductive screens, XLPE insulation, a metallic layer, and an outer sheath, with water-blocking or armor features selected for the installation. The exact design is not universal: buyers should confirm the governing standard, network conditions, installation method, and accessories before comparing quotations. In this guide, we explain the key specifications and the information we recommend preparing for supplier discussions.
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We prepared this guide for utility procurement teams, EPC contractors, consultants, and industrial project buyers evaluating 64/110kV cable systems. It is intended to support preliminary technical review rather than replace a project specification or engineering approval. If you are sourcing cable for a new route, replacement project, or substation connection, use the points below to structure your questions to manufacturers.
The voltage designation describes the relationship between the cable’s rated voltage and the network. In the commonly used notation 64/110 (123) kV, 64 kV is the rated voltage between conductor and earth, 110 kV is the rated voltage between conductors, and 123 kV is the highest system voltage associated with the class. Confirm the notation required by the project’s governing standard, since designation practices and specification details can vary by market.
Voltage class alone does not establish whether a cable is suitable for a particular route. System earthing, operating conditions, short-circuit requirements, installation environment, and accessories all affect the final design. We recommend asking the project engineer to approve the complete cable system, not just the nominal voltage printed on a data sheet.
A single-core extruded 64/110kV cable commonly uses a conductor surrounded by a conductor screen, XLPE insulation, and an insulation screen. A metallic screen or sheath is applied outside the insulation system, followed by protective bedding or layers and an outer sheath. Depending on the design and route, additional longitudinal or radial water barriers and mechanical protection may be specified.
| Component | Purpose and specification considerations |
|---|---|
| Conductor | Copper or aluminum may be considered; confirm material, cross-sectional area, stranding, and electrical requirements. |
| Semiconductive screens | Provide smooth interfaces around the insulation; request the specified screen design and manufacturing requirements. |
| XLPE insulation | Provides the main dielectric insulation; confirm thickness and applicable design and test requirements. |
| Metallic screen or sheath | Provides a defined electrical path and may contribute to fault-current performance; specify material and cross-section. |
| Outer sheath and optional protection | Protects the cable from its service environment; select compounds and additional barriers to suit the route. |
This sequence is a general reference, not a complete manufacturing drawing. The actual arrangement can change with the cable standard, system design, conductor choice, and environmental requirements. We advise buyers to request a cross-sectional drawing and construction schedule that match the project specification.
Copper and aluminum are common conductor options, but the appropriate choice depends on electrical design, cable dimensions, installation constraints, and total project cost. The conductor cross-sectional area should be determined from the required current, route conditions, permissible voltage drop, and short-circuit duty. Buyers should avoid choosing a size based only on a general catalogue example, because ampacity depends on installation and operating assumptions.
The metallic screen or sheath must also be defined for its intended electrical function. Its material, effective cross-section, bonding arrangement, and fault-current duty should be coordinated with the system design. For single-core AC circuits, cable arrangement and bonding can affect induced sheath voltages and losses, so these details should be reviewed by the project’s cable-system engineer.
XLPE is widely used as the insulation material in extruded high-voltage cables. Buyers should confirm the specified insulation design, screen requirements, and relevant routine, sample, and type-test documentation under the applicable standard. Do not assume that two cables are equivalent solely because both are described as XLPE and carry the same voltage designation.
For routes exposed to moisture or water ingress risk, ask whether longitudinal water blocking, radial barriers, or other protective measures are required. The outer sheath material should be selected for the installation environment, such as direct burial, ducts, tunnels, or exposed sections. Where mechanical protection is needed, confirm whether armor is appropriate and how it interacts with electrical design, installation, and accessories.
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For buried routes, project teams should assess soil thermal conditions, route depth, spacing, backfill, water exposure, and the need for mechanical protection. For duct installations, pulling tension, sidewall pressure, duct fill, and bends can influence cable selection and installation planning. Tunnel and industrial applications may add requirements for fire performance, smoke characteristics, or environmental resistance, depending on local rules and project specifications.
Submarine or water-crossing sections require a purpose-designed solution rather than a standard land-cable assumption. The route, water depth, mechanical loads, jointing strategy, and installation vessel or method may all affect construction. We recommend treating these sections as a separate engineering package and asking suppliers to identify any design limitations clearly.
We find that a clear technical schedule helps suppliers identify exceptions before commercial comparison begins. Ask each bidder to list assumptions, deviations, and items excluded from the offer instead of relying on a headline price. This makes it easier to compare equivalent constructions and reduces the risk of late clarification during engineering or procurement.
One common mistake is treating voltage class as a complete specification while leaving conductor size, screen design, and installation conditions undefined. Another is requesting a generic current rating without giving the route and thermal assumptions used to calculate it. Buyers should also check that the quoted cable, accessories, test documents, and installation requirements are consistent with the same project standard and system design.
The price of a 64/110kV cable depends on the approved construction, conductor material and size, order quantity, drum length, accessories, testing scope, packaging, and delivery terms. Copper or aluminum selection and the amount of metallic material can materially affect the bill of materials, while customized barriers or mechanical protection may change production planning. We recommend requesting a quotation against a complete specification rather than using an indicative price as a final budget figure.
Minimum order quantities and production lead times are supplier- and project-specific, so they should be confirmed in writing after technical review. Long cable lengths, special construction details, testing arrangements, and export logistics may affect the schedule. For planning, ask for the proposed production sequence, inspection hold points, shipment assumptions, and the validity period of the commercial offer.
When evaluating a supplier, review its experience with the requested voltage class and construction, ability to provide technical drawings, and clarity in responding to deviations. Confirm what quality records and test documentation will be supplied, and establish whether inspections or witnessing are included in the offer. Ask how the supplier will coordinate questions involving accessories, cable-system design, packing, and delivery.
At Zhongdong Cable Co., Ltd., we encourage buyers to share their project data sheet and route conditions before requesting a final offer. This allows our team to discuss conductor and sheath options, clarify construction requirements, and identify information that still needs engineering confirmation. The buyer remains responsible for ensuring that the final selection meets the project’s system design and applicable approval requirements.
A 64/110kV high voltage cable specification should define more than its voltage class: it should cover conductor, insulation system, metallic layer, outer protection, installation conditions, testing, accessories, and applicable standards. The practical next step is to prepare a project data sheet with network and route information, then request a construction drawing and a written list of assumptions from each supplier. This approach gives technical teams a sound basis for review and helps procurement compare offers on an equivalent scope.
If you are preparing a 64/110kV cable inquiry, send Zhongdong Cable Co., Ltd. the required standard, conductor details, route conditions, approximate quantity, delivery destination, and target schedule. We can use these details to discuss a suitable specification and prepare a project quotation for your review.
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