LV Switch Panel Condition & Remedial

Rust in the switch panel. The cause? A leaking ceiling.

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 Circuits checked by hand

6 Circuit breakers exposed to the leak

£40–60K

Recommended budget

3–6

Months window to complete the works

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 main copper bars (busbars).

What We Found

Every connection tight — six devices in question

An LV switch panel is the building’s main electrical board: power arrives from the grid and is split out to every floor. If it fails, the building loses power. Every connection was safe, but six sealed breakers have been getting wet for years and can’t be opened to check, so they should be replaced. Every termination in the panel was checked and confirmed tight. The six are the breakers (MCCBs) out of eleven that sit on the side of the panel exposed to the leak.

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. The recommended option keeps the parts confirmed in good condition; the alternative replaces them too.

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 — 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