The core reason is that the higher the current, the higher the physical space requirements for the conductors, arc extinction, insulation and internal structures inside the switch, so the overall size and volume of the switch inevitably increase.
The details are as follows:
1.The conductor materials must be thick enough to avoid overheating and burnout
When current flows through the metal components of a high-current rocker switch, heat will be generated. The higher the current, the larger the cross-sectional area of copper or silver conductors is required to reduce resistance. Thick conductors cannot be installed in a narrow space. If made compact forcibly, the components will be damaged by high temperature or even catch fire.
2.Sufficient space is required for arc extinction
High-temperature electric arcs will be generated when switching on and off high current. Adequate internal space and arc quenching plates are needed to stretch and cool the arcs. If the size is too small, the arcs cannot be extinguished quickly, which will burn out the contacts and cause short circuits.
3.Sufficient safety insulation distance must be reserved
Circuits equipped with high-current rocker switches usually work with relatively high voltage. After the contacts are disconnected, the electrical clearance and creepage distance shall comply with mandatory safety standards. Reducing the size will lead to insufficient distance, which may cause electric leakage, breakdown and arc flash accidents.
4.The mechanical structure needs to be reinforced
Strong electric impact force will be produced during the switching of high current. The contacts, springs and operating mechanisms all need to be thickened and reinforced. A compact structure lacks sufficient strength and is prone to deformation, jamming and fracture.
Conclusion: Restricted by four physical factors including heat generation, electric arc, insulation and mechanical strength, high-current switches cannot be made small in size.