Supplier selection should begin with project conditions, not a low unit price. In international installations, enclosure ratings, ambient temperature, altitude, and switching frequency can change performance. Ask suppliers for clear datasheets, material declarations, inspection records, and traceable batch information. Their engineering team should explain limitations without hiding behind generic compliance statements. A responsive supplier matters when drawings change late.

Testing must reflect real site conditions. Review dielectric strength, insulation resistance, temperature-rise, mechanical endurance, and ingress protection results. Request reports from competent, independent laboratories where practical. Compare the tested configuration with the delivered product. Small differences in terminals, housings, or accessories can invalidate assumptions. Factory acceptance testing may reveal loose hardware or unclear markings before shipment.

It is not perfect.

Lifecycle cost includes more than purchase and freight. Estimate installation time, spare parts, inspection access, replacement intervals, energy losses, and disposal requirements. A durable isolator may cost more initially but reduce shutdown risks. However, durability claims need evidence, not attractive wording. Check whether replacement parts remain available across the planned operating period. Standardised components can simplify training and maintenance, although excessive standardisation may ignore harsh local conditions. Keep a risk register and update it after commissioning. Field feedback often exposes weaknesses that laboratory testing misses.