The 7 most common power tool breakdowns caused by moisture and how to prevent them
Identify the most common faults and avoid costly breakdowns in your power tools

Humidity is one of the silent enemies of any power tool. It makes no noise, gives no warning, and when it does appear, it usually manifests as intermittent malfunctions, loss of power, or even sparks. In an environment like the Costa del Sol—with garages, storage rooms, and construction sites exposed to sudden temperature changes—it's common for many tools to arrive at our workshop with symptoms directly related to humidity.

In this article we tell you the most frequent breakdowns, how to identify them in time and what you can do to prevent your tools from deteriorating prematurely.

🔧 1. Switches locked or unresponsive

Moisture seeps into the internal mechanism of the switch, oxidizing contacts or generating small layers of compacted dirt.

Symptoms:

  • The button is stiff or doesn't return to its position.

  • The tool only starts sometimes.

  • The switch needs to be "forced".

What NOT to do: Force the button or apply household lubricants.

When to bring it to the workshop:  If the switch fails more than once, it's a sign that the problem is already inside.

⚡ 2. Excessive sparking in the engine

A classic problem. Humidity affects the brushes and the commutator, causing larger than normal sparks.

Symptoms:

  • Sparks visible through the ventilation slots.

  • Smell of burning.

  • Power loss.

Risk:  Ignoring it can burn out the engine.

🌀 3. Loss of power or weak start-up

Humidity affects the windings and internal contacts.

Symptoms:

  • The tool starts off “slow”.

  • It stops under load.

  • It stops under load.

Most Common Cause:  Condensation accumulated in storage rooms or garages.

🔩 4. Rust on screws and internal casing

Rust is not just aesthetic: it can deform parts and block mechanisms.

Symptoms:

  • Screws that won't come out.

  • Cases that don't close properly.

  • Abnormal vibrations.

🔌 5. Swollen or rigid cables

Humidity deteriorates the cable's insulation, making it more fragile.

Symptoms:

  • Rigid cable or cable with "bulges".

  • Small cracks in the rubber.

  • Abnormal heating.

Risk:  Electrical shocks or short circuits.

🛑 6. Corroded electronic boards

In modern tools, humidity can directly attack the electronics.

Symptoms:

  • Intermittent failures.

  • The tool turns itself off.

  • Flashing lights or indicators.

Solution:  Professional inspection. Not repairable at home.

🧽 7. Accumulation of damp dust inside

Dust mixed with moisture becomes a conductive paste that causes short circuits.

Symptoms:

  • Damp smell

  • Odd noises

  • Obstructed ventilation.

🛡️ How to prevent moisture in your tools

  • Store the tools in a dry, ventilated place.

  • Avoid storage rooms without insulation.

  • Use moisture-absorbing bags or desiccants.

  • Clean off the dust after each use.

  • Do not store wet tools after working outdoors.

  • Check cables and plugs every few months.

When to bring your tool to Almuco

If you notice any of these symptoms:

  • Burning smell

  • Excessive sparks

  • Weak start

  • Switches that fail

  • Abnormal vibrations

  • Power loss

At our store in Mijas We check the tool, diagnose the fault, and give you a clear solution: repair, replace, or rent an alternative if you need it immediately.


Does your tool exhibit any of these symptoms?  Bring it to our workshop in Mijas and we'll check it out. If you need to continue working on it, we offerimmediate rental of equivalent tools.

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