In short. Old switchgear may still carry load but can lack spares, safety features and protection capability. Start with a condition and risk assessment, then choose between refurbishing, retrofitting breakers or relays, partial replacement or full replacement, planning outages carefully.
Signs it is time to act
- Spares and manufacturer support are no longer available.
- Fault level has grown beyond the rating.
- Frequent breaker failures or slow operation.
- Old electromechanical relays with limited functions and no records.
- Arc-flash hazard or lack of safe operation features.
- Need for new functions such as remote monitoring, paralleling or hybrid integration.
Condition assessment
- Review drawings, history, loads and fault level.
- Inspect visually, with thermography, partial discharge where applicable.
- Test breakers, insulation, contact resistance and protection.
- Assess busbar and enclosure condition.
- Rank risks by consequence and likelihood.
Options
| Option | Description | Considerations |
|---|---|---|
| Refurbishment | Clean, repair, replace worn parts | Lowest cost, limited by obsolescence |
| Retrofit breakers | Replace breaker elements with modern ones in existing cubicles | Needs compatible dimensions and approvals |
| Relay replacement | Numerical relays replace electromechanical | Adds functions and records; wiring changes |
| Partial replacement | Replace critical sections or panels | Staged outages |
| Full replacement | New switchgear | Highest cost and outage, best long-term result |
Planning the work
- Plan outages with the operations team, using temporary supply (rental generator or temporary bus) where needed. See rental power.
- Stage the work to maintain critical loads.
- Re-run the short-circuit and coordination study with new equipment. See coordination.
- Test and commission as for new equipment.
- Update drawings, labels and procedures.
Illustrative example
A 30-year-old generator panel has obsolete relays and a breaker with no spare parts. The decision is to replace the relays with a multifunction numerical relay, retrofit the breaker element, keep the enclosure and busbar after inspection, and add a sync-check relay. The work is done in a weekend outage with a temporary generator supplying the critical load.
Why modernise
Older switchgear may lack spares, use electromechanical relays, offer limited breaking capacity for today’s fault levels and provide no data. Replacement of everything is expensive, so retrofit options matter.
Options
| Option | Scope | Notes |
|---|---|---|
| Relay upgrade | Replace old relays with numerical ones | Better protection and records, panel stays |
| Breaker retrofit | Replace breaker with a modern unit in the existing cubicle | Needs a compatible design and type-test support |
| Panel refurbishment | Replace busbar insulation, clean, re-torque | Extends life where the structure is sound |
| Full replacement | New switchboard | Best when fault rating or structure is inadequate |
Assessment steps
- Check present and future fault level against equipment rating.
- Inspect condition, history and availability of spares.
- Review protection adequacy and coordination.
- Plan outage and staging so critical loads remain supplied.
Practical hazards
Retrofit work often involves live adjacent sections. Plan isolation, safe procedures and temporary supply. Generators on site can support loads during the work. See upgrade and replacement planning.
After retrofit
Re-run protection studies, commission fully and update drawings and labels. See testing and commissioning.
Common mistakes
- Retrofitting without updating the studies.
- Underestimating outage needs.
- Mixing new and old without checking compatibility.
What to send us
Send drawings, photos and history. Send your application details. See also upgrade and replacement planning.
Questions engineers ask
Is retrofit cheaper than replacement?
Usually, up front. Whole-life cost and risk should be compared.
Can new breakers fit old cubicles?
Often with retrofit kits, but verify design approvals and ratings.
Do I need a new study after retrofit?
Yes, because ratings, settings and fault levels may change.
How can I keep power on during the work?
With staged outages and temporary supplies.
This guide gives general principles. Decisions need inspection and testing of your switchgear.