Every case study is a named client, a documented outcome, and a verifiable result. No composite stories. No estimated savings. The numbers below came from actual invoices, actual downtime logs, and actual fault records.
Harwick Steel Group ran four rolling mill sites across South Yorkshire on continuous production schedules. Their incumbent contractor had flagged no anomalies in 18 months. An internal audit suggested the picture was very different. Harwick needed a second opinion — fast, and without stopping the line.
Two Caldwell engineering teams deployed across all four sites over a single planned weekend. Using partial discharge detection and thermal imaging simultaneously, we identified 17 fault conditions — 4 rated critical, requiring immediate remediation. All work completed within the 6-hour production window. Full signed report delivered within 48 hours.
All 4 critical faults remediated within 3 weeks. Zero unplanned production stops in the 12 months following the survey. Harwick's engineering director calculated £2.4M in avoided downtime cost based on their standard line-stop rate of £140,000 per hour.
A Manchester colocation facility operating at Tier III standard had deferred its full electrical inspection for 26 months due to the difficulty of scheduling around tenant SLA obligations. Their compliance window was closing. Any unplanned outage during testing would trigger six-figure penalty clauses with three anchor tenants.
Caldwell developed a phased testing programme across 6 consecutive Saturday maintenance windows — 4 hours per window, coordinated with the facility's operations team and pre-notified to all tenants. Non-invasive thermal and PD testing was conducted live during trading hours where permitted, reducing the outage-dependent scope by 40%.
Full EICR completed. 22 fault conditions identified and remediated across the 6-week programme — 3 of which were rated serious and would have caused unplanned outages within the following quarter. Zero SLA breaches. Full compliance documentation submitted to the client's regulator on time.
Strathmore Wind had a 34-turbine onshore wind project in Perthshire approaching its grid connection date. Their original commissioning contractor had withdrawn at short notice. With a G99 compliance deadline immovable and ROC revenue starting from connection date, they needed a full electrical commissioning team on-site within two weeks.
Caldwell mobilised a 6-engineer commissioning team within 11 days. Full HV testing of all 34 turbine transformers, collection system cables, and the 33kV substation. During testing, 8 transformer insulation faults were identified — all pre-energisation, all remediated before grid connection. G99 protection relay settings verified and documented for submission.
Grid connection achieved on the original deadline. Zero defects post-energisation. The 8 transformer faults, if missed, would have caused sequential failures estimated at £3.7M in generation loss and replacement costs over the first 5 years of operation. Full commissioning documentation pack delivered within 72 hours of connection.
Every project above started with a 30-minute scoping call. Fixed quote within 24 hours. The engineer who scopes the job runs the test. No handoffs.