FZW32-12 Outdoor Load Break Switch 12kV 20kA | High-Voltage Switchgear Equipment for Power Systems | IEC Certified

Product Overview

The FZW32-12/630-20 is an outdoor three-pole vacuum load break switch for 50 Hz, 12 kV distribution networks. Vacuum interrupters take over the breaking duty while the isolating knives leave a clearly visible open gap, so one unit performs both load switching and sectioning on the pole. Fitted with a spring or motor operating mechanism and a controller, the switch also serves as a sectionalizing device or an automatic line divider on urban and rural overhead feeders.

Product Display

FZW32-12 Outdoor High-Voltage Vacuum Load Break Switch - display

FZW32-12 Outdoor High-Voltage Vacuum Load Break Switch - poster_display

Model Designation

FZW32-12 Outdoor High-Voltage Vacuum Load Break Switch - model

Model format: FZW32-12/T 630-20 (also written FZW32-12/630-20)

F – load break switch
Z – vacuum
W – outdoor type
32 – design sequence number
12 – rated voltage, kV
T – spring operating mechanism
630 – rated current, A
20 – rated short-time withstand current, kA
Optional suffix behind the mechanism symbol – control arrangement (manual spring, motorised, or controller for automatic line division)

Service Conditions

Ambient temperature: +40 ℃ maximum, -40 ℃ minimum
Altitude: not more than 1000 m; higher sites require a correspondingly higher insulation level
Wind pressure: not more than 700 Pa, equivalent to a wind speed of 34 m/s
Seismic intensity: not more than 8 degrees
Pollution level: IV
Maximum daily temperature difference: not more than 25 K
Relative humidity: daily average ≤ 95%, monthly average ≤ 90%
No flammable gas, explosion risk, chemical corrosion or severe vibration

Construction

The three poles are mounted on a common steel frame, each pole combining a vacuum interrupter with an isolating knife on porcelain composite columns for outdoor duty at pollution level IV. The isolating knives are driven by a spring-over-centre mechanism with three-pole ganged operation, which fixes the opening simultaneity of the interrupters at the factory.

A quick-acting mechanism sets the interrupter travel speed independently of the operator, so arcing time does not depend on how fast the handle is moved. In service the switch makes and breaks rated load current, closed-loop transfer current, cable charging current and capacitor bank current, while short-circuit current is cleared by back-up fuses or upstream protection.

Technical Data

No.	Item	Unit	Parameter
1	Rated voltage	kV	12
2	Rated frequency	Hz	50
3	Rated current	A	630
4	Rated active load breaking current	A	630
5	Rated closed-loop breaking current	A	630
6	5% rated active load breaking current	A	31.5
7	Rated cable charging breaking current	A	10
8	Rated capacitor bank breaking current	A	100
9	1 min power-frequency withstand voltage (vacuum gap / phase and earth / isolating gap)	kV	42/48
10	Lightning impulse withstand voltage (phase and earth / isolating gap)	kV	75/85
11	Rated short-time withstand current	kA	20
12	Rated short-circuit duration	s	4
13	Rated peak withstand current	kA	50
14	Rated short-circuit making current	kA	50
15	Mechanical life	operations	10000
16	Three-pole opening and closing simultaneity	ms	≤ 5

Selection note: Fix the switching duty first: the standard unit is 630 A with 20 kA for 4 s short-time withstand, and the prospective short-circuit level of the line must be confirmed so that back-up fuse coordination can be checked. Then choose manual spring operation for simple sectionalizing or a motor mechanism with controller for automatic line division and remote tripping, and state the mounting mode and pole diameter at order.

Standards

Performance conforms to GB 3804, AC high-voltage load break switches for 3.6 kV to 40.5 kV, and to the applicable IEC recommendations for outdoor AC switching devices used on distribution networks. Full type tests and long-running service experience support the ratings given in the technical table.

Technical note: Sites above 1000 m altitude, motorised or controller-equipped schemes and non-standard fuse coordination fall outside the tabulated values and are subject to agreement between manufacturer and purchaser. Final parameters follow nameplate data and the approved specification.

Installation & Dimensions

Installation Diagram

FZW32-12 Outdoor High-Voltage Vacuum Load Break Switch - installation

Choose the mounting mode and prepare the matching hardware: side mounting uses the lead wire terminal, pole, long and short support brackets, cable outlet and power supply cable, while horizontal and pole-top mounting use the switch support component, support arm, terminal, shaped pull rod and end cable. Level the frame before torquing the clamps, then charge the spring by hand, confirm close, open and trip actions, check the open-gap indication on all three poles and verify that three-pole simultaneity stays within 5 ms. Before energisation carry out the 1 min power-frequency withstand test on the main circuit, bond the frame to the earth network and re-check terminal clearances against the approved outline drawing. A potential transformer supplies the electric operating mechanism where motorised operation is ordered.

Mounting mode	Overall width (mm)	Phase spacing (mm)
Horizontal pole mounting	1300	750 + 320
Side mounting	1230	500 + 500
Pole-top mounting	1050	400 + 400

Safety notice: Installation, operation and maintenance must be performed by qualified professionals. Before maintenance open the switch, confirm the visible isolating gap, close the earth switch or apply portable earthing and verify absence of voltage. Do not use the load break switch to interrupt short-circuit current, and do not operate the mechanism with the frame unearthed.

FAQs

It is an outdoor three-phase vacuum load break switch for 12 kV, 50 Hz urban and rural overhead distribution networks. It makes and breaks load current, sections the line for maintenance with a visible open gap, and when fitted with a motor mechanism and controller it works as a sectionalizing or automatic line-dividing device.

F stands for load break switch, Z for vacuum, W for outdoor type and 32 for the design sequence number; 12 is the rated voltage in kV, T the spring operating mechanism, 630 the rated current in amperes and 20 the rated short-time withstand current in kA. An optional suffix behind the mechanism symbol states the control arrangement.

The vacuum interrupter quenches the arc when load current is broken, while the isolating knives provide the air insulation of an open gap once the pole is apart. That combination gives load switching and sectioning in a single pole-mounted unit, so crews see a positive break point without fitting a separate disconnector.

No. The switch carries and withstands short-circuit current, rated 20 kA for 4 s with a 50 kA peak, but it is not a short-circuit breaking device. Faults are cleared by back-up fuses on combination units or by upstream protection; the 10 A cable charging and 100 A capacitor bank ratings are the only non-load breaking duties.

Horizontal pole mounting occupies 1300 mm overall width with 750 mm and 320 mm phase spacing, side mounting 1230 mm with 500 mm and 500 mm, and pole-top mounting 1050 mm with 400 mm and 400 mm. Matching brackets, pole clamps, strain clamps and clevis fittings are ordered together with the switch.

All are outdoor vacuum switching devices with a visible isolating gap but at different voltages and duties: the FZW-40.5 covers 40.5 kV lines at 1250 A, the FZW32-12 covers 12 kV feeders at 630 A with 20 kA short-time withstand, and the FZW28Z-12 is a compact pole-mounted sectionalizer. A ZW32-24 vacuum circuit breaker trips fault current itself, whereas load break switches rely on fuses or upstream protection.

FZW32-12 Outdoor High-Voltage Vacuum Load Break Switch