Every commercial and industrial building in the UK depends on its LV switchgear to distribute electricity safely. Knowing when to replace it, rather than repair it again, is what prevents fires, downtime and costly emergency call-outs.
Did You Know…?
- Most LV switchgear has a working life of 20 to 30 years, though enclosures and busbars can last 40 to 60 years with the right maintenance regime.
- The main triggers for replacement are; it being over 25 to 30 years old, frequent faults, overheating, corrosion or damage, and a lack of available spare parts.
- Repairing old switchgear isn’t always the safest or cheapest option. Once components become obsolete, every repair carries more risk than it removes.
- A planned, phased replacement avoids the disruption and cost of an emergency shutdown, and gives you a natural point to add monitoring and capacity for future loads.
What is LV Switchgear and Why Does its Condition Matter?
Low-voltage (LV) switchgear is the primary electrical distribution equipment in a building, operating at voltages up to 1,000V AC. It protects equipment, distributes power to everything connected to it, and allows for emergency switching and isolation when something goes wrong.
A typical board includes a main incoming air circuit breaker or moulded case circuit breaker, busbars, outgoing breakers, changeover or ATS switches, surge protection, metering, and auxiliary circuits such as indication contacts and protection relays.
This is the backbone of the electrical installation in offices, factories, data centres, hospitals and industrial sites. When it fails, the consequences aren’t minor: fire risk, electric shock, extended outages and business interruption.
The Electricity at Work Regulations 1989 require electrical systems to be maintained to prevent danger, and BS 7671 and BS EN 61439 set the technical standards for design, verification and inspection. Condition isn’t just a maintenance question. It’s a compliance one.
Key Signs That it’s Time to Upgrade:
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Age and wear
Equipment older than 25 to 30 years is working against degraded insulation, metal fatigue and parts that are increasingly hard to source. Age on its own doesn’t mean a board needs replacing, but it’s the point at which every other sign below starts to matter more.
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Physical and thermal damage
Discoloured busbar insulation, browning around cable terminations, melted plastic or a persistent burning smell are all signs of overheating that shouldn’t wait for the next scheduled visit. Thermal imaging picks up these issues long before they’re visible to the naked eye.
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Increased power demand
EV charging points, new plant or a change in how a building is used can push a board beyond what it was designed for. If load has grown since the switchgear was installed, capacity is worth checking against the original design.
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Frequent faults
Breakers tripping without a clear downstream cause – or main incomers tripping under normal load – point to stress building up inside the assembly. Resetting isn’t a fix, it’s a delay.
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Compliance failures
Recurring defects on an EICR, or a board that no longer meets current segregation or fault protection standards, is a clear signal that refurbishment alone won’t be enough.
How We Approach Switchgear Replacement
Not every ageing board necessarily needs full replacement. We assess each site on its condition, criticality and how much disruption a shutdown can tolerate, and recommend repair, refurbishment, retrofit or full replacement accordingly. Where full replacement is the right call, the challenge is rarely the engineering. It’s delivering it without stopping the building from working.
That’s the project we delivered at International House, St Katharine Docks: a full replacement of nine main LV switchboards, planned and delivered through a series of weekend shutdowns so the building stayed fully operational during the week. The scope covered isolation planning, meter relocation, surge protection upgrades and enhanced resilience measures, alongside specialist support throughout.
Benefits of Replacing Ageing LV Switchgear with Modern Systems
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Safety
Modern switchgear improves arc fault protection and fault discrimination, gives clearer labelling, and makes isolation safer for everyone working on or around the system.
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Operational
Higher fault current ratings support increased loads, including EV charging and new plant, while reducing the risk of unplanned outages.
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Monitoring
Integrated metering and power quality monitoring support a conditional maintenance approach, so issues are caught before they become failures.
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Sustainability
Reduced energy losses and better power factor correction mean a modern board doesn’t just perform better, it costs less to run.
FAQs
Which warning signs should I be looking out for?
Frequent tripping, overheating or a burning smell, visible corrosion or damage, and recurring defects on an EICR. One issue on its own might be repairable. Several together, on the same board, usually means it’s time for a proper condition assessment.
When should LV switchgear be replaced rather than repaired?
When the board is unsafe, uneconomical to keep maintaining, or can’t support the loads that a building now needs. As a rule of thumb, boards over 25 to 30 years old with obsolete components or rising call-out frequency are better replaced than repaired again.
Is it cheaper to keep repairing old switchgear rather than replacing it?
Not usually, once you add up the cost. Individual repairs look cheap in isolation, but frequent call-outs, downtime and falling efficiency add up over several years. A modern board also loses less energy, which offsets part of the capital cost over its lifetime.
How disruptive is switchgear replacement to a live, occupied building?
It depends on planning, not on the scale of the work. At International House, a full replacement of nine switchboards was delivered through weekend shutdowns specifically so the building stayed operational Monday to Friday. Phased shutdowns, careful isolation planning and out-of-hours working are what make large-scale replacement possible without closing a building down.
Can I replace just the main circuit breaker instead of the whole board?
Sometimes, if it’s properly engineered and type-verified against the rest of the assembly. But if other parts, (i.e. busbars, outgoing breakers, insulation) are ageing too, replacing only the main breaker leaves the wider risk in place. Worth getting a condition assessment before deciding.