Machine Shop — Contacts & Refurbishment · 2025

ConEd Disconnect Switch
Silver Contact Rebuild

An antiquated ConEd distribution disconnect switch — one of the hardest outages to get in New York, feeding Arthur Ashe Stadium — arrived with contacts loose from repeated failed solder repairs. Southern Switch machined silver inserts, refurbished the full switch, and returned it in under 24 hours.

01 — The Failure
Solder melts.
Silver doesn’t.

The circuit feeds Arthur Ashe Stadium, home of the US Open. Getting an outage on it requires months of advance coordination — the kind of window that doesn’t come often. ConEd had attempted contact repairs with solder multiple times, but every repair failed when the switch returned to load. Solder’s melting point is around 180 °C. Contact temperatures under normal service current easily exceed that. The repair was never going to hold.

Rather than attempt another temporary fix, ConEd hotshotted the switch to Southern Switch. The brief: refurbish it right and get it back fast. The outage window was short.

15 kV
Distribution-class disconnect switch
<24 hrs
Refurb to return — hotshot both ways
Silver
Machined inserts — moving arm & stationary contacts
ConEd distribution disconnect switch as received at Southern Switch — full assembly with porcelain insulator, blade arm, and visible corrosion and wear on contact surfaces.
As received — full assembly The ConEd disconnect switch on arrival at our facility. The porcelain insulator, blade arm, and contact hardware are intact, but decades of service and the failed solder repairs had left the contact surfaces in poor condition.
Close-up of ConEd disconnect switch stationary contact terminal with blue-green solder corrosion buildup from repeated failed repairs.
Solder failure — stationary contact The stationary contact terminal on arrival. The blue-green corrosion is characteristic of oxidized solder — multiple repair attempts had built up layers of material that flowed, cooled, and corroded each time the switch returned to service under load.
As received — contact movement The contact point as received, demonstrating the play in the blade contact. A properly assembled disconnect should have zero lateral movement here. The loose contact is the result of solder flowing out of the joint under service heat, leaving the contact unseated.
02 — The Work
Silver inserts machined.
Full switch refurbished.

Southern Switch disassembled the switch, cleaned all components, and machined silver inserts for both the moving blade arm contacts and the stationary contacts. Silver was selected specifically because it will not fail under service load heat — its melting point is approximately 960 °C, compared to 180 °C for the solder ConEd had previously used. The repair does not need to hold by friction or by hope; it holds by material properties.

The full switch was cleaned, inspected, and rebuilt. The mechanism hardware, pivot points, and insulators were checked throughout. The switch was returned to ConEd via hotshot courier within 24 hours of arrival.

Contact work
  • →Old solder and corroded material fully removed
  • →Silver inserts machined for moving arm contacts
  • →Silver inserts machined for stationary contacts
  • →Contacts fitted, aligned, and verified
Full refurbishment
  • →Full disassembly to components
  • →Complete cleaning of all hardware
  • →Pivot, mechanism, and insulator inspection
  • →Full rebuild and return via hotshot courier
Side-by-side comparison at Southern Switch — original corroded ConEd disconnect contact (top) versus the new machined copper replacement contact with silver insert (bottom).
Before and after — contact blocks The original corroded contact block (top) alongside the new machined copper replacement (bottom). The old contact shows solder buildup, oxidation, and surface pitting from decades of service and repeated repair attempts. The new block is clean copper, ready to receive the silver insert.
Close-up of the silver ring insert at the blade pivot point on the refurbished ConEd disconnect switch — machined silver contact visible at the blade tip boss.
Moving arm — silver insert at pivot The machined silver insert at the pivot contact of the blade arm. The silver is pressed and secured into the copper boss at the blade tip — this is the point that carries current through the pivot joint, and it is the joint most vulnerable to heat-related solder failure.
Machined silver insert plate on the stationary contact face of a refurbished ConEd distribution disconnect switch — bright silver contact surface on copper and brass assembly.
Stationary contact — silver insert face The machined silver insert on the stationary contact face. The bright silver surface sits flush against the copper and brass assembly — a precisely fitted insert, not a patch. This is the mating face that the blade closes against; a consistent, high-conductivity surface here eliminates the resistance hotspot that the previous solder repairs created.
Fully refurbished ConEd disconnect switch blade arm on the workbench at Southern Switch — cleaned copper arm with silver contacts installed and all hardware replaced.
Refurbished blade arm — ready for reassembly The cleaned and refurbished blade arm ahead of final reassembly. The copper is cleaned back to bare metal, the silver contacts are installed, and the hardware is replaced. The arm had been in service long enough that the cleaning alone required significant work.
03 — Why Silver Works
960 °C melting point.
Not 180 °C.

The failure mode on the ConEd switch was not unusual. Solder is sometimes used in the field to re-seat contacts because it’s accessible, fast, and doesn’t require machining. The problem is physics. Contacts on a loaded circuit generate heat, and once contact resistance rises from wear or misalignment, the heat increases further. A solder repair softens, flows, and shifts — which increases resistance, which generates more heat, which accelerates the failure.

Silver has a melting point around 960 °C. It will not flow under any temperature a distribution switch sees in normal service. It also has excellent electrical conductivity — lower contact resistance means less heat generated at the joint to begin with. The silver insert is the correct solution, not a temporary one.

Southern Switch machines silver inserts for disconnect switch contacts, circuit breaker contacts, and other high-current interfaces where the OEM contact material is worn, damaged, or has been field-repaired with a material that won’t hold.

Silver vs. Solder

Solder melts at approximately 180 °C — well within the range of contact temperatures on a loaded circuit. Silver melts at approximately 960 °C. If the contact runs hot, solder fails and silver doesn’t. The choice matters.

Machined, Not Patched

Silver inserts are precision-machined to fit the contact housing exactly. The insert is mechanically retained — not bonded with a soft material that can flow. Dimensional accuracy at the contact surface determines electrical performance.

Moving and Stationary Contacts

Both mating surfaces were upgraded. Rebuilding only the moving arm while leaving the stationary contact in its original degraded state would have set up the same failure pattern. The repair is only complete when both contact faces are correct.

24-Hour Turnaround

When an outage window is short and the switch serves a critical load, turnaround matters as much as quality. Southern Switch refurbished this switch and returned it via hotshot the same day it arrived. Precision work does not have to mean long lead times.

Have a switch with worn or failed contacts?

Call (727) 789-0951 or send us the switch. Southern Switch machines silver inserts for disconnect contacts, circuit breaker contacts, and other high-current interfaces. If it’s been repaired with solder and it keeps failing, we can fix it properly.

Get in touch → Machine Shop →
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