Description
Mounted directly on the busbar, an NH fuse switch disconnector turns a busbar run into a fuse-protected feeder group. The device combines the switching function, visible isolation and fuse protection in one unit, so no additional sub-distribution is needed inside the assembly.
Why mount the switch on the bar
- No sub-distribution: feeders are tapped and protected at the point where they leave the busbar.
- Visible isolation: the switch opens with a visible break before the fuse is changed.
- High breaking capacity: the NH link covers high prospective short-circuit currents in a compact device.
- Load breaking: the switch makes and breaks load current, so it can be used as a feeder or main switch.
Technical data
| Parameter | Range / value |
|---|---|
| Mounting | Direct on 2T / 3T / TCC busbar system, or on a mounting plate |
| Fuse system | NH fuse links (NH000 to NH4), same system as the HR and NH switch disconnectors |
| Operation | Load break switch disconnector with visible isolation |
| Fuse monitoring | Optional fuse monitoring and signal switch |
| Terminals | Top and bottom cable connection; cable sizes per terminal data |
| Design standard | IEC 60947-3 / GB 14048.3; fuse operation to IEC 60269-2 |
Operating conditions
NH fuse switch disconnectors are operated according to IEC 60269-2 and VDE 0105-100: by qualified electrical personnel only, opening the switch before a fuse is changed, and keeping the cover closed in normal operation. Where the cover is partly open the fuse may still be live, so only the handle is operated.
Selection notes
- Size the NH link to the cable it protects, not only to the load, and check the link against the prospective short-circuit current.
- Choose gG links for cable and line protection, aM links for motor feeders with a separate overload relay.
- Add a fuse monitoring switch where a single-phase loss would damage motors or where the installation is unattended.
Ordering information
State the NH size, rated current, number of poles, whether the device is for busbar or panel mounting, and whether monitoring is required.
FAQ
Can the switch be mounted on any busbar profile?
Yes. The NH fuse switch disconnectors mount on the 2T, 3T and TCC busbar systems, and can also be mounted on a plate where the busbar is not used.
Which fuse links fit the switch?
The switch uses the same NH system as the HR and NH switch disconnectors, from NH000 to NH4, in gG or aM characteristic as required by the circuit.
What happens when one fuse operates?
The switch opens all three phases when a fuse operates, so the faulted feeder is isolated completely instead of running single-phased.
Is fuse monitoring available?
Yes. A fuse monitoring and signal switch can be fitted so a blown fuse is reported to the control system.
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