Fuse switch disconnect are suitable for AC 50Hz, rated voltage up to 660V, and DC voltage up to 440V. They are low-voltage power distribution components integrating isolation, switching, and short-circuit protection functions. The fuse is installed in the knife arm position of the moving contact of the disconnecting switch, or a combination of disconnecting switch and fuse connected in series is installed. The fuse interrupts short-circuit current, thus providing short-circuit breaking capability.

Technical Parameters

GRGLR-400/4F

GR: Company code
GLR: Fused disconnect
400: Rated current
4: 4 phrase
F: Front operation

Product features

The fuse switch disconnect assembly has a modular structure, featuring a glass fiber reinforced unsaturated polyester resin shell, spring energy storage, and a bevel gear transmission acceleration mechanism for rapid connection and disconnection.

The fuse element is connected in series in a four-break multi-contact structure, automatically determining the limit positions of the on/off states and providing clear contact status indication.

Technical parameters

Code			GRGLR-400
Conventional heating current (A)			400
Rated insulation voltage (V)			800
Rated impulse withstand voltage (kV)			8
Rated working current (A)	380V		400
	660V		315
Rated making and breaking capacity (A) 1.05Ue	AC660V,AC-23B	Connect	4000
	COSΦ:0.35
	AC660V,AC-23B	Disconnect	3200
	COSΦ:0.35
Mechanical life (times)			800
Electrical life (times)			200
Operating force (N)			30
Rated short-circuit current (kA)			50
Pollution degree			3

Dimension:

product-1390-594

product-1216-662

Operating methods

Direct side operation: Handle is installed on the right side of the switch;

Direct front operation: Handle is installed on the front of the switch;

External side operation: Handle is installed on the right side outside the distribution cabinet;

External front operation: Handle is installed on the front outside the distribution cabinet door.

Routine Maintenance

Visual Inspection

Check the casing for cracks and burn marks; ensure the transparent cover is free of dust and condensation.

The "Open (O) - Close (I)" markings on the operating handle should be clear, without looseness or discoloration.

Electrical Connection Check

Use an infrared thermometer to check the temperature of the wiring terminals. During normal operation, the temperature should be ≤ ambient temperature + 40℃, with no overheating (terminal discoloration, insulation aging).

Manually and gently shake the copper busbar/cable to confirm it is secure (if there is abnormal noise, retighten it).

Contacts and Fuses

After disconnecting the power annually, inspect the contact surface: if there is slight burning, smooth it with fine sandpaper; if the contacts are welded or deformed, replace the switch body. If a fuse blows, replace it with the same model (NT2).

Operating Mechanism

Apply a small amount of lubricant (such as silicone grease) to the handle rotation shaft every six months to ensure smooth operation. Verify the interlocking function: After closing the switch, try to open the cabinet door; confirm that it cannot be opened; when the cabinet door is open, the switch cannot be closed.

Applications of Disconnectors

In low-voltage power distribution systems, the main function of disconnectors is for inspection and maintenance safety.

1. Incoming lines at distribution boxes and panels

2. Incoming lines at the main circuit of motor control centers

3. Feeders leading out from low-voltage distribution cabinets in substations; when fuses are used as protective electrical devices, disconnector switch-fuse groups should be installed.

4. Data centers and similar locations

5. Isolation requirements for special locations

Isolation requirements for solar photovoltaic power supply devices