Drop-out Fuse
Drop-out fuses for 12 kV to 40.5 kV distribution, 100 A and 200 A, with 5 kA to 8 kA breaking capacity.
- Rated voltage
- 12–40.5 kV
- Rated current
- 100 and 200 A
- Breaking capacity
- 5.0–8.0 kA
- Support
- Porcelain or composite
A drop-out fuse protects a branch line or a distribution transformer. When the element melts, the fuse tube swings down and hangs open: the break is visible from the ground, and the fault is isolated without sending someone up the pole to find it.
The tube is held closed by the fuse link itself, so a link of the right length is what keeps the fuse in service. The link is chosen for the transformer rating, not for the line rating.
Seven series are listed, from the small RW7 at 12 kV to the PRWG2 at 40.5 kV. Types with H in the prefix use a composite support; the rest are porcelain.
Reading the Type Code
The type reads as family, design, voltage and current, with prefix letters for the support:
- RW
- Drop-out fuse, plain type
- H
- Composite support instead of porcelain
- PRWG
- Improved drop-out fuse; RXWO is the current-limiting type
- 10 / 12
- Design number and rated voltage, kV
- 100 / 200
- Rated current, A
- F
- Load-breaking version with an arc chute
Specifications
Values published for each type.
| Type | Rated voltagekV | Rated currentA | Breaking currentkA | Lightning impulse withstandkV | Power-frequency withstand, 1 minkV | Creepagemm | Weightkg |
|---|---|---|---|---|---|---|---|
| RW7-12/100 | 12 | 100 | 6.3 | 110 | 42 | 240 | 5.5 |
| RW7-12/200 | 12 | 200 | 8 | 110 | 42 | 240 | 5.5 |
| HRW7-12/100 | 12 | 100 | 6.3 | 110 | 42 | 345 | 4.4 |
| HRW7-12/200 | 12 | 200 | 8 | 110 | 42 | 345 | 4.4 |
| RW10-12/100 | 12 | 100 | 6.3 | 110 | 42 | 260 | 6.2 |
| RW10-12/200 | 12 | 200 | 8 | 110 | 42 | 260 | 6.2 |
| HRW10-12/100 | 12 | 100 | 6.3 | 110 | 42 | 345 | 4.4 |
| HRW10-12/200 | 12 | 200 | 8 | 110 | 42 | 345 | 4.4 |
| RW10-12F/100 | 12 | 100 | 6.3 | 110 | 42 | 260 | 6.7 |
| RW10-12F/200 | 12 | 200 | 8 | 110 | 42 | 260 | 6.7 |
| HRW10-12F/100 | 12 | 100 | 6.3 | 110 | 42 | 345 | 4.9 |
| HRW10-12F/200 | 12 | 200 | 8 | 110 | 42 | 345 | 4.9 |
| RW11-12/100 | 12 | 100 | 6.3 | 110 | 42 | 230 | 6 |
| RW11-12/200 | 12 | 200 | 8 | 110 | 42 | 230 | 6 |
| HRW11-12/100 | 12 | 100 | 6.3 | 110 | 42 | 350 | 4 |
| HRW11-12/200 | 12 | 200 | 8 | 110 | 42 | 350 | 4 |
| RW12-12/100 | 15 | 100 | 6.3 | 110 | 42 | 300 | 7.5 |
| RW12-12/200 | 15 | 200 | 8 | 110 | 42 | 300 | 7.5 |
| HRW12-12/100 | 15 | 100 | 6.3 | 110 | 42 | 380 | 5.7 |
| HRW12-12/200 | 15 | 200 | 8 | 110 | 42 | 380 | 5.7 |
| RW5-40.5/100 | 40.5 | 100 | 5 | 185 | 105 | 746 | 23 |
| RW5-40.5/200 | 40.5 | 200 | 8 | 185 | 105 | 746 | 23 |
| HRW5-40.5/100 | 40.5 | 100 | 5 | 185 | 105 | 980 | 16 |
| HRW5-40.5/200 | 40.5 | 200 | 8 | 185 | 105 | 980 | 16 |
| PRWG2-40.5/100 | 40.5 | 100 | 5 | 185 | 105 | 935 | 20 |
| PRWG2-40.5/200 | 40.5 | 200 | 8 | 185 | 105 | 935 | 20 |
| HPRWG2-40.5/100 | 40.5 | 100 | 5 | 185 | 105 | 1440 | 9 |
| HPRWG2-40.5/200 | 40.5 | 200 | 8 | 185 | 105 | 1440 | 9 |
F types break rated load current as well as fault current, 100 A or 200 A to match the rating. RW12-12 types are rated 15 kV; the designation follows the catalogue. Operating conditions: ambient −40 °C to +40 °C, altitude up to 1 000 m, supply frequency 50 ± 2 Hz.
Choosing a Type
Load-breaking Types
F types carry an arc chute and can open the rated load current. Plain RW types are for fault current only and are operated off load.
Composite Support
The H prefix marks a composite support: 1.5 kg to 11 kg lighter than the porcelain version, and it does not shatter when the fuse operates.
Every fuse is routine-tested before it is packed, and each type is type-tested before it is offered for supply.
Ask about Drop-out Fuse
Send the type designation, the quantity and the standard the project is working to. We reply with a price and a delivery date.
We usually reply within one working day.