Function And Operation Of High Voltage Isolating Switch

Power-off sequence: first turn off the circuit breaker, then pull High Voltage Disconnect Switch

Power-on sequence: first close the isolating switch, then close the circuit breaker

(Mnemonic: "first turn off and then disconnect" when powering off, "first disconnect and then close" when powering on)

Core function ③: small current separation and combination, specializing in "difficult and complicated diseases"

🔧 Three types of special current separation and combination

Although the isolating switch has no arc extinguishing ability, it is more than enough to deal with the following small currents:

No-load current: such as disconnecting a transformer without load

Capacitor current: handles the charging and discharging of capacitor banks

Circulating current operation: balancing current when switching between double busbars

💥 Taboo red line

No load operation: circuits above the rated current must be cut off with a circuit breaker first

Use with caution on rainy days: arcs are easily triggered when air humidity is greater than 80%

Hidden skill ④: prevent misoperation, mechanical interlocking to ensure safety

🔒 Double insurance mechanism

High-end isolating switches are equipped with mechanical interlocking devices , to achieve:

When the circuit breaker is not disconnected: the isolating switch cannot be operated

When the grounding knife switch is not closed: the main knife switch cannot be closed

(Some models also support electromagnetic lock + electrical interlock)

🏠 Home application

The isolating switch in the distribution box is linked with the leakage protection

Anti-backflow isolation when the photovoltaic system is connected to the grid

Model selection guide: Only the right medicine can be used

1. The first choice for home: HL32 small isolating switch

Parameters: 230V/400V, below 100A

Advantages: small size, with double confirmation function, one-click to cut off the power supply of the whole house

2. Factory must-have: GW outdoor high-voltage type

Parameters: above 10kV, wind and sand resistance and corrosion resistance

Black technology: single-column design saves space, contacts are silver-plated to prevent oxidation

3. Railway exclusive: 27.5kV electrified isolating switch

Features: with arc extinguishing rod, suitable for frequent contact network operation

Common problem first aid kit

Q1: Can't push the isolating switch up after the home trips?
👉 First check whether the circuit breaker is completely disconnected, the linkage device may be stuck

Q2: Is the isolating switch hot and has a burning smell?

👉 Turn off the power immediately! Poor contact of the contacts leads to increased resistance, which needs to be polished or replaced

Q3: Can the outdoor type be installed indoors?

👉 Strictly prohibited! The insulation spacing of the outdoor type is larger, and indoor installation is prone to short circuit

Q4: How to upgrade the old knife switch?

👉 Replace it with a rotary isolating switch with an arc extinguishing cover, which increases safety by 3 times

👉 Tips for using isolating switches

Turn off the power first for maintenance, and operate in order
Can handle small currents and avoid large loads
Interlocking is the bottom line, and grounding ensures safety
Select according to the scene, and the life span is doubled