Minimum order quantity for insulators, and when it can be waived

Yes, there is a minimum, and it is not arbitrary

Most manufacturers set minimum order quantities on insulators, and the level varies by type and specification. For standard insulators at common voltage classes such as 10 kV, 35 kV and 110 kV, the minimum is usually 50 to 200 units per type. That figure is not a commercial preference; it is roughly the quantity below which a kiln run and a set of forming tools cannot be justified.

Customised units carry a higher floor

Insulators made to special specifications, for polluted areas or high-altitude regions, generally carry a minimum of 200 to 500 units per type. The difference is mould opening and production line adjustment, both of which are fixed costs that have to be spread across the run.

Large projects change the conversation

For wholesale and project supply, minimum order quantities can be waived when the total order volume is large enough, in the region of 10,000 units and above. At that point the question stops being whether a run is viable and becomes how the schedule is phased against your construction programme.

How to get a better answer than a price

Send the full schedule rather than one line item. A schedule that mixes several types across one project is usually easier to quote well than a single type in isolation, because the types share kiln time. This is particularly true on rural electrification orders, where spool, shackle and pin insulators are ordered together.