Quod Scire Debēs de Mālfunctionibus Commutātorum Oneris

Salve, ego sum Blue — iam plus quam 20 annos operor ut electricus ingeniarius.
Magnam partem meae carinae dedi ad circuit breakers designandos, transformers administrandos, et adiuvandos power companies in omnibus generibus problematum systematis electrici.

Hodie, amicus ab Asiae Meridionalis me rogavit:

"Quae sunt communia mala load switches?"

Bona quaestio! Igitur dissecemus in simplicibus terminis — sine technicis verbis, sed cum rebus quas possis in opere aut durante maintenance videre.

Primum, Quid Est Load Switch?

Antequam de problematibus loquimur, breviter recapitulemus quid sit load switch.

Load switch est quasi on/off commutator gravis usus in systematibus medium-voltage (sicut 10kV, 20kV grids). Potest facere et rumpere normales currentes operativi, sed non fault currents — hoc est quod circuit breakers sunt pro.

Igitur cogita eum ut "medius" inter regularem commutatorem et plenam circuit breaker. Simplicior, vilior, et saepe in distribution networks, praesertim in locis ubi protection coordination non est super complexa.

Nunc, Loquamur de Communibus Malis

In meis annis operis agri et troubleshooting, vidi haec problemata iterum et iterum. Hic est index communium malorum:

1. Infirmatio Claudi vel Aperiendi Recte

Hoc est valde commune, praesertim in vetustioribus instrumentis.

Sometimes the switch won’t close even when you press the button.

Aut claudit, sed statim aperit.

Potest etiam in clausa positione esse fixus et nolle aperire.

Cur hoc fit?

Partes mechanicas tempore deficiunt — linkages obstruantur, springs debiles, latches misaligned.

Circuits control might have loose wires or burned relays.

Sometimes the motor operator (if electrically operated) fails.

Exemplum real-life:

Olim operatus sum in loco ubi load switch noluisset claudere quia parvus clavus in mechanismum ceciderat et motum impediebat. Duxit nos duas horas invenire!

2. Overheating vel Burning Smell

Si olfacis aliquid ardens iuxta load switch panel, ne ignore.

Overheating usually happens at the contacts or terminal connections.

Can lead to insulation damage, melting parts, or even fire if not fixed early.

Causes:

Loose cable connections — high resistance = heat.

Contacts getting old or pitted — bad contact surface.

Excessive current flow beyond rated capacity (overloading).

Tip: Always check the temperature regularly using infrared thermography. If a connection is more than 10–15°C hotter than others, investigate ASAP.

3. Arcing vel Flashover During Operation

Audis populum fortis, forsitan et vide scintillas — hoc est arcing.

Happens mostly during opening/closing operations.

Dangerous, can damage components or cause injury.

Common reasons:

Main contacts worn out — gaps not maintained properly.

Dust or moisture inside the chamber — lowers insulation level.

Operating under load when it shouldn’t be (e.g., switching off a large motor without a circuit breaker upstream).

Note: Load switches are not meant to interrupt fault currents, only normal load currents. If you’re trying to cut through a short-circuit current, expect trouble.

4. Mechanical Wear and Tear

Load switches are mechanical devices. They move parts, so they wear out eventually.

Bearings, gears, and levers all degrade over time.

Especially true in environments with dust, salt spray, or extreme temperatures.

Prevention tip: Regular preventive maintenance (PM) is key. Lubricate moving parts, inspect linkages, and replace worn-out components before they fail.

5. Control Circuit Failures

The control side is just as important as the main circuit.

Indicator lights stop working.

Remote operation fails.

Local buttons don’t respond.

Typical causes:

Blown fuses in the control circuit.

Corroded terminals or broken wires.

PLC or RTU communication errors (in automated systems).

Quick fix idea: Use a multimeter to trace voltage drop and continuity. Start simple — check fuses first.

6. Moisture and Corrosion Inside the Enclosure

Especially common in coastal areas or humid climates.

Moisture gets into the switchgear cabinet.

Causes rust, corrosion, and reduced insulation levels.

Symptoms:

Tripping for no apparent reason.

Arcing even under light load.

Bad smell or condensation visible inside the box.

Solution: Make sure the enclosure has proper sealing and desiccant packs. In tropical areas, consider adding space heaters or dehumidifiers.

7. Wrong Operation by Personnel

Human error is still one of the biggest causes of failures.

Someone tries to open the switch under heavy load.

Or operates the switch without checking interlocks.

Even worse — someone forgets to lock out/tag out before maintenance.

Lesson learned: Training matters. Clear labeling helps. And always follow safety procedures.

Final Thoughts

Like any electrical equipment, load switches aren’t perfect. But with good design, regular maintenance, and proper operation, most of these faults can be avoided or caught early.

As someone who’s been in the field for over two decades, my advice is:

“Don’t wait for a failure to remind you that maintenance is important.”

If you're dealing with a faulty load switch and want help troubleshooting or choosing replacements, feel free to reach out. Happy to share more stories (and some war scars) from the field.

Stay safe, and keep the lights on!

— Blue