Copper Tungsten Components for MV Switchgear: A Sourcing Guide
If you're building or refurbishing medium-voltage switchgear, copper tungsten (CuW) shows up in more places than just the obvious arc contacts. Shielding caps, conductive rods, contact plates, guide pins. The CuW family covers a dozen distinct component types, each for a specific job inside a vacuum interrupter or switchgear assembly. This guide walks through which CuW component fits which application, so you can match the right part to your design or sourcing requirement.
For the full product range, see the Copper Tungsten (CuW) Series. This article is the "which one do I need" companion.
Start With the Application, Not the Part
The most common sourcing mistake is starting from a part name without being clear on the application. CuW components divide into a few functional groups:
- Arc contacts: handle the arc during make/break in a vacuum interrupter
- Vapor management: shielding caps that protect the ceramic envelope
- Current path: conductive rods and conductor elements
- Specialty / structural: guide pins, contact plates, custom geometries
Identify which group your need falls into first; the specific part follows.
Arc Contacts: Static, Moving, or Pair
The heart of a vacuum interrupter is the contact pair. When the breaker opens, the arc forms between a fixed (static) and a moving contact. Both are CuW; both see comparable arc duty.
- CuW Static Arc Contact: the fixed-side contact. Order this when replacing or sourcing the static half specifically.
- CuW Moving Arc Contact: the moving-side contact, attached to the operating shaft.
- CuW Arc Contact Pair: both halves as a matched set from one material lot. For new VCB builds, this is the cleanest sourcing path; one material certification covers the pair.
- CuW70 Vacuum Interrupter Contact: general-purpose CuW70 contact when the role isn't specifically static or moving.
For the grade decision (CuW70 vs 75 vs 80), see our grade selection guide. The short version: CuW70 for standard 12/24 kV duty, higher grades for severe arc duty or 40.5 kV+.
Vapor Management: Shielding Caps
Inside the sealed vacuum interrupter, metal vapor comes off the arc. If it reaches the ceramic-to-metal seal, it degrades insulation over time. The CuW Shielding Cap condenses that vapor before it gets there.
Order a shielding cap when you're manufacturing sealed-tube vacuum interrupters or refurbishing VI assemblies. CuW70 and CuW75 are the typical grades; the cap doesn't need the highest tungsten content because its job is vapor condensation and dimensional stability, not arc duty.
Current Path: Rods, Conductors, Elements
Where a switchgear current path needs arc-resistant material at a specific segment, CuW conductor stock fills the role:
- CuW Conductive Rod: raw rod stock for in-house machining into contacts or custom parts.
- CuW Conductor (Basic): near-final conductor element for the current path.
- CuW Contact Plate: flat or stepped plate for earthing switches and larger contact assemblies.
If you have your own machining capability, ordering rod stock and finishing in-house is usually the most cost-effective. If you'd rather receive finished parts, order the machined components.
Contact Elements and Fingers
For assemblies that combine CuW with copper carriers:
- CuW Contact Finger: finger-style contact with a CuW tip for plug-in assemblies that see arc duty.
- CuW Contact Element: small braze-on insert; puts CuW only where the arc strikes, keeping cost down.
These are the right choice when your assembly's carrier handles the current and you need CuW only at the arc interface.
Custom Geometries
When none of the standard forms fit:
- CuW Alloy Custom Component: machined to your drawing. Most of our CuW work is custom; if you have a unique geometry, send the drawing.
- CuW Guide Pin: for VI assemblies where a guide pin sits close enough to the arc gap to need arc resistance. Note: most guide pins are steel or aluminum; specify CuW only if arc exposure is real.
A Decision Path
A practical way to navigate the CuW family:
- Is it an arc contact in a VI? → Static / Moving / Pair (use the pair for new builds)
- Is it for vapor management? → Shielding Cap
- Is it a current-path segment? → Conductive Rod or Conductor
- Is it a small arc-resistant insert on a carrier? → Contact Element or Contact Finger
- None of the above? → Custom Component: send the drawing
Specifying Your Order
Whatever the part, the specification should cover: CuW grade (70/75/80), dimensions per drawing, voltage class (12/24/40.5 kV), surface treatment (as machined / silver / nickel plated), and quantity. All our CuW is produced to meet GB/T 8320-2025 minimums; certified material documentation is available per lot.
When in doubt about which component you need, send the assembly drawing or a sample of the part you're replacing. We'll point you to the right listing.
Related Reading
- How to Choose CuW70 vs CuW75 vs CuW80: grade selection
- Copper Tungsten Properties Guide: material reference
- Static vs Moving Arc Contact: how the contact pair works
- Copper Tungsten (CuW) Series: full product range