LV Switch Panel Condition & Remedial

Office Building

Commercial Property Owner · UK

An intrusive inspection that found every electrical connection sound — and traced the real problem to a building leak, not a wiring fault.

15 Outgoing ways inspected

6 MCCBs on the ingress side

£40–60K

Recommended budget

3–6

Months, recommended timing

The Situation

A panel due a second look

A previous appraisal a few years earlier found the panel in generally good condition and recommended a review within five years. Corrosion and signs of water ingress inside the panel brought TI back in early.

Our Approach

Open every cover, test every connection

TI safely isolated the panel and opened every cover and shroud, tightness-checking all fifteen outgoing ways, the earth bar, and the main incomer busbars.

What We Found

Every connection tight — six devices in question

Every termination in the panel was checked and confirmed tight — no loose connections anywhere. But six of the eleven MCCBs sit on a side of the panel exposed to long-standing water ingress, and being sealed, non-serviceable devices, their internal condition after years of intermittent damp can’t be verified.

Rust in the riser compartment

Corrosion across the top, sides and floor of the far-right busbar compartment.

The real root cause

A hairline crack in the soffit above the panel — years of intermittent leaking, not a wiring fault.

No sign of overheating

Thermal indicator labels on the main busbars remain unchanged across their full range.

Clean, despite the rust nearby

The terminal closest to the heaviest corrosion on the panel — still clean, still tight.

The Recommendation

Two remedial options

Two options were costed. Only one disturbs equipment that TI’s inspection confirmed is already in good condition.

Option 1 — Recommended

£40–60K

Retain the main switch and incoming cable chamber — both confirmed in good condition. Replace the outgoing-ways section as a whole with a new panel.

Option 2 — Alternative

£75–130K

Strip out the entire panel and re-terminate every circuit — including the main switch section that doesn’t need it.

Between £15K and £90K saved by replacing only what’s actually compromised — without disturbing equipment already confirmed sound.

What Actually Changes

How the recommended option works

The panel is split along the line shown below — the left-hand main switch and incoming cable chamber stay in service; everything to the right, including the water-damaged end, is replaced with a new wall-mounted panel.

Retained

Main switch & incoming cable chamber

Replaced

Entire outgoing-ways section — new wall-mounted panel

Separately

Ceiling leak — waterproofing specialist required