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Office Trips Under Load: Wiring Worn at a Tight Bend

An office trips under load and a control part is quoted. Load is also when a cable works hardest, which points somewhere else.

By Team Snowflake | Updated 24 Aug 2026

How this presents

Communication faults on a system whose condenser sits in a cramped position, forcing the cabling into a sharp turn where it enters. The rest of the run is straight and well supported. The faults are intermittent and have worsened gradually over time.

Setup
Samsung Wall-mounted13-15 yearsOfficeSingapore River
Misread as
A control fault requiring parts, on a system installed in an awkward position.
Check first
The tightest bend on the run, measured against the cable's specification

What else produces this

A well-supported run with one sharp bend has a single obvious candidate, and looking there first costs nothing. Insulation forced round a radius tighter than the cable allows is stretched on the outside of the curve and compressed on the inside, and both weaken it. Add years of thermal movement and the material fails at exactly that point. The tightest bend deserves checking before any electrical test.

  1. A straight, well-supported run everywhere else leaves one bend as the only stressed point.

  2. A turn far tighter than the cable's minimum radius stresses insulation permanently at that spot.

  3. Insulation cracked on the outside face of that curve locates the failure precisely and unambiguously.

  4. A gradual worsening across years matches material fatigue rather than any single damaging event.

Why it happens

Cable insulation tolerates being bent within a specified radius and no further. Forced tighter it is permanently stretched on the outer face, and that stress does not relax with time. Thermal cycling then works the material at its weakest point until it cracks and the conductor is exposed. The installation was tidy and everything else about it is correct; the position simply did not leave room for a proper turn.

What resolution involves

The bend is opened out to a proper radius, which usually means a small change in how the cable approaches the unit rather than a different cable. Where the position genuinely cannot accommodate it, a more flexible cable type or a purpose-made entry solves it. The point worth carrying is that a cramped position is a design constraint on the cabling too, not only on the equipment.

How to tell it worked

The bend radius measured against the cable's own specification rather than judged by eye. A turn that looks acceptable can still be well inside the limit for the cable being used.

Before you approve a quote

The tightest bend is where the cable will fail

  • Minimum bend radius is a limit, not a guideline. Beyond it, insulation is permanently stressed.
  • On a well-supported run, the sharpest turn is the only stressed point. Check it before testing.
  • A cramped position constrains the cabling as much as the equipment. Plan the entry accordingly.

Questions this case answers

Why does my aircon trip the breaker only on hot afternoons?
Because the insulation is permanently stretched on the outside of the curve and compressed on the inside. That stress does not relax, and thermal movement works the weakened material until it cracks.
What does a load-linked trip suggest about the compressor?
It is specified for the cable and stated by the manufacturer, usually as a multiple of the cable's diameter. The important part is that it is a limit rather than a suggestion, and eyeballing it is unreliable.
Aircon wiring in a heritage building: what makes it wear out?
Opening the bend out to a proper radius, which often only needs a small change in how the cable approaches the unit. Where the space genuinely will not allow it, a more flexible cable type solves the same problem.
What is worth inspecting before a compressor gets replaced?
Yes, and that is worth knowing before an installation is agreed. A cramped position constrains where cable can run just as much as it constrains the equipment, and the entry deserves planning rather than improvising.

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