RN1-6KV/RN3-10KV Indoor High-voltage Current-limiting Fuse | Power Line Overload and Short-circuit Protection

I. Overview

The RN1 and RN3 indoor high-voltage current-limiting fuses are used for overload and short-circuit protection of power lines. Current-limiting means the fuse interrupts the short-circuit current before it reaches its peak value.
Fusing characteristics: When the current through the fuse is 1.3 times its rated current, it will not melt within 1 hour. The RN1-6KV/RN3-10KV indoor high-voltage current-limiting fuse has excellent current-limiting characteristics and can effectively protect power equipment.

II. Application

The RN1 and RN3 high-voltage indoor fuses are used for overload and short-circuit protection of power lines. These fuses have high breaking capacity and can also be used to protect branches of the power system. The fuse interrupts the line before the short-circuit current reaches its maximum value, making it an ideal device for protecting power equipment from damage.

III. High-voltage Fuse Structure

The RN1 and RN3 fuses consist of four parts: two post insulators, contact bases, a fuse tube, and a base plate. The post insulators are mounted on the base plate, the contact bases are fixed to the post insulators, and the fuse tube is placed and secured in the contact bases. The copper caps at both ends are fitted onto the ceramic tube. Inside the fuse tube, the fuse element is wound around a grooved core (for rated currents below 7.5A) or wound into a spiral shape and installed directly inside the tube (for rated currents above 7.5A), then filled with quartz sand. The end caps are pressed tight and soldered to maintain a seal.
When an overload or short-circuit current passes through, the fuse element melts immediately, creating an arc. The quartz sand extinguishes the arc instantly. When the fuse element melts, the spring tension wire also melts and pops out of the spring, indicating that the fuse has operated.

IV. High-voltage Fuse Operating Instructions

※ The RN1 and RN3 indoor quartz sand-filled fuses are suitable for:
(1) Altitudes not exceeding 1000 meters.
(2) Ambient temperatures not exceeding +40C and not below -40C.

※ The RN1 and RN3 fuses cannot operate in the following environments:
(1) Indoor locations with relative humidity exceeding 95%.
(2) Locations with fire or explosion hazards.
(3) Locations with severe vibration, oscillation, or impact.
(4) Areas with altitudes exceeding 2000 meters.
(5) Air-polluted areas and specially humid locations.
(6) Special locations (such as use in X-ray devices).

V. Fuse Link Structure

The fuse link is the main component of the fuse. It consists of a fuse element placed in a ceramic tube filled with quartz sand, with both ends sealed. For rated currents below 7.5A and rated voltage of 35V, the fuse element is wound on a special ceramic core, as shown in Figure 2.a. For rated currents above 7.5A, the fuse element is suspended inside the ceramic tube, as shown in Figure 2.b.

VI. External and Installation Dimensions

Ensure that for the RN1-6KV/RN3-10KV indoor high-voltage current-limiting fuse, the RN1-6KV/RN3-10KV current-limiting fuse for power line protection has a rated current range of 2~200A. During installation, ensure the fuse tube nameplate faces outward for easy inspection. The fuse indicator should be visible on the end face of the fuse tube. Regularly check for discoloration of the fuse tube due to abnormal temperature rise.