The invention relates to a conjunction box without power loss during replacement, and belongs to high-supply high-metering and high-supply low-metering electric energy metering devices. Electricity is metered normally when the metering device as a collection terminal and an electric energy meter is replaced, and the conjunction box is prevented from power loss when a secondary loop is powered off transiently. The conjunction box is characterized in that a voltage loop connecting part is provided, four holes are formed in a T-shaped copper tube at the voltage wire inlet end at the bottom of the conjunction box, each of two linear copper tubes is provided with three holes at the wire outlet end in the upper portion of the conjunction box, the wire outlet end is connected with the T-shaped copper tube at the wire inlet end by cooperating two separate loops with two connection sheets respectively, and power supply of one voltage loop is not influenced when the connection sheet, cooperating with the other voltage loop, is disconnected. The conjunction box provided by the invention can be used to ensure that the electricity is metered normally in the wiring process of instruments during onsite examination.