US Patent 11831110 Electrical connector

An electrical connector has a test terminal, a positive terminal, and a negative terminal coaxially mounted in a connector base. The negative terminal surrounds the positive terminal. An insulating cap is mounted between the positive terminal and the negative terminal. A pair of turning engaging parts is formed between the ring body of the insulating cap and the internal surface of the negative terminal and the turning engaging parts are engaged with each other to assemble the insulating cap with the negative terminal by turning the insulating cap. An annular groove is formed in a top of the insulating cap to increase a creepage distance between the negative terminal and the positive terminal to meet requirement of safety specifications.