According to Faraday’s law of induction a magnetic field will interact with a circuit and produce an electromagnetic induction.  An electric transformer is a device used for transferring electrical energy from one circuit to another.

Transformer can be step up or step down voltage in electric power applications or can be used in signal processing circuits.

Large transformers may require cooling system to protect itself from the heat generated while in operation. Cooling can be water cooling, force air or oil cooling or a combination of one or more.

Polychlorinated biphenyls (PCB) were once used as a dielectric coolant in transformers. However, as Polychlorinated biphenyls (PCB) is a persistent organic pollutant its use is reduced/stopped in electrical transformers. Some of the new transformers use nitrogen or sulphur hexafluoride gas as coolant.

Persistent Organic Pollutants (POP) are known as “forever chemicals” as they resist environmental degradation through chemical, biological and photolytic processes. These POPs bioaccumulate and will adversely affect human health and environment.

The Stockholm Convention of United Nations Environment Programme (UNEP) known as “Stockholm Convention on Persistent Organic Pollutants” lists polychlorinated biphenyls (PCB) among the “dirty dozen”.

1. Aldrin
2. Chlordane
3. Dieldrin
4. Endrin
5. Heptachlor
6. Hexachlorobenzene
7. Mirex
8. Toxaphene
9. Polychlorinated biphenyls
10. Dichlorodiphenytrichloroethane
11. Dioxins
12. Polychlorinated dibenzofurans

Entries in IMDG Code covering electric transformers, condensers include

• POLYCHLORINATED BIPHENYLS, LIQUID  Class  9 UN2315
• POLYCHLORINATED BIPHENYLS, SOLID  Class 9 UN 3432
• POLYHALOGENATED BIPHENYLS, LIQUID or
• HALOGENATED MONOMETHYLDIPHENYLMETHANES, LIQUID or POLYHALOGENATED TERPHENYLS, LIQUID Class 9 UN 3151

Products such as rags, cotton waste, clothing or sawdust, containing polychlorinated biphenyls, polyhalogenated biphenyls or polyhalogenated terphenyls where no free visible liquid is present must be assigned to UN 3432.

Electric transformers or condensers containing polychlorinated biphenyls transported for disposal or recycling will fall under Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal.

If the shipment is falling under Basel Convention, then the transport can only commence when

1. notification has been sent by the competent authority of the country of origin, or by the generator or exporter through the channel of the competent authority of the country of origin, to the country of final destination; and
2. the competent authority of the country of origin, having received the written consent of the country of final destination stating that the wastes will be safely incinerated or treated by other methods of disposal, has given authorization to the movement.

Together with dangerous goods declaration the shipment must also be accompanied by “waste movement document”.