Export Packaging and Logistics for Magnetic Components

Packaging Is Where Good Magnetics Fail

A transformer that passes every electrical test can still arrive at the customer’s dock with shifted laminations, cracked bobbins, corroded terminals, or a failed hipot after a month in a humid container. The cause is almost always packaging and transport rather than design. For a heavy, brittle, magnetically sensitive, and often moisture-sensitive component, the shipping specification deserves the same attention as the electrical drawing.

This guide covers the packaging decisions that matter for ocean and air freight, and what a buyer should require on the drawing.

Failure Modes in Transit

Transport failure modes and the packaging response
Failure	Cause	Response
Core stack shifted, gap changed	Impact, vibration, loose clamping	Individual part in a rigid tray; foam insert; carton drop test
Bobbin cracked	Compression from stacking	Layer pads with defined count per layer; carton height limit
Terminal corrosion or oxidation	Humidity in transit, no barrier	VCI or aluminium barrier bag with desiccant; humidity indicator
IR drop / hipot failure after arrival	Moisture absorption in an unimpregnated winding	Moisture barrier bag, desiccant quantity calculated by volume and transit days
Lead wire crimped or broken	Bulk packing without support	Leads sleeved and tied; no loose bulk bag for parts with leads
Inductance shift on arrival	Mechanical stress on a stress-sensitive core (nanocrystalline)	Clamped fixture retained in the packaging

Moisture Protection for Ocean Freight

A container crossing an ocean sees large temperature swings, and condensate forms inside cartons. For impregnated parts the risk is moderate; for unimpregnated or potted-but-hygroscopic designs it is real. The practical rule: any part whose insulation resistance specification matters should ship in a sealed barrier bag with desiccant sized for the carton volume and the transit duration, plus a humidity indicator card. Calculate desiccant in units of “grams per litre of enclosed volume” per the desiccant supplier’s method, not by habit.

Wood, Pallets and Regulations

Solid wood pallets must be heat-treated or fumigated to ISPM 15 and marked with the IPPC stamp. Plywood and processed wood are exempt in most markets, which is why many exporters switch to plywood crates. Buyers should require the stamp to be visible on the pallet, because a shipment without it can be refused or delayed at the border regardless of the cargo’s quality.

Weight, Stacking and the Damage Threshold

Magnetic components are dense. A carton of 500 VA transformers can weigh 25 kg, and stacking three high loads the bottom layer heavily. Specify the maximum stack height and the carton compression strength, and use layer pads that distribute the load rather than transferring it through the bobbin. For heavy parts, individual foam cradles or a wooden crate are cheaper than the scrap they prevent.

What to Put on the Drawing and the PO

Unit packaging: tray type, quantity per layer, layers per carton, carton weight.
Protective packaging: barrier bag, desiccant quantity, humidity indicator.
Pallet: type (plywood or ISPM 15 heat-treated), quantity per pallet, max stack, pallet weight and dimensions.
Labels: part number, quantity, lot, date code, and country of origin, in the language of the destination.
Drop and vibration test requirements per a defined standard.
Unpacking instructions for parts that must not be re-packed without a clamp.