Error after neighbour's renovation: cable insulation nicked

An E1 error showed up days after the next unit was renovated, and the homeowner feared a damaged control board. The timing pointed elsewhere. Drilling had nicked the communication cable, leaving bare wire touching metal trunking on and off, and no parts were replaced.

By Team Snowflake | Updated 28 Jul 2026

Case summary

Samsung Wall-mounted3-7 years oldHDBJurong West, Singapore

Concern: The renovation next door seemed to have damaged the indoor control board, making a costly board replacement unavoidable.
Found: Communication cable insulation damaged during renovation causing intermittent short
Key check: Traced cable route through ceiling void. Found nicked insulation where cable crossed renovation drilling path
Result: The E1 error cleared the moment the cable was repaired, and the unit has run without interruption since. No parts were replaced, so the homeowner avoided the board cost they had feared.

What we were told

The aircon began showing an error a few days after the next unit was renovated. Nobody had touched the unit, yet the error turned up around the same time. It came and went, running fine for hours before the error returned.

What we checked

The timing did most of the talking. An error that appeared right after nearby renovation pointed to physical damage to the wiring, not a part wearing out on its own. So we traced the cable route first, before testing any components.

The E1 error was intermittent. The unit ran normally for stretches, then faulted, which rarely happens with a truly dead board.
Both the indoor and outdoor control boards had power and responded to reset commands, so neither board was failed.
The communication cable showed good continuity when the unit sat still. That ruled out a clean break and pointed to a fault that depends on movement.
Tracing the cable through the ceiling void revealed a nick in the insulation, right where the cable crossed the drilling path from next door.
The bare copper at the nick was resting against the metal trunking. Whether the two touched depended on where the cable sat, which explained the on-and-off fault.

What we found

Drilling during the neighbour's renovation nicked the communication cable in the shared ceiling void. The exposed copper then sat against a run of metal trunking. When vibration or heat shifted the cable, the bare section touched the trunking and caused a brief short. That short scrambled the signal between the indoor and outdoor units, which is what the E1 code reports.

What fixed it

We sealed the nicked insulation with heat-shrink tubing, then used cable ties to hold the cable clear of the trunking so the two could not touch again. No parts were replaced. The control boards, the wiring, and the rest of the unit were all undamaged. We also advised the homeowner to photograph the damage, in case they wanted to claim against the renovation contractor.

Outcome

The E1 error cleared the moment the cable was repaired, and the unit has run without interruption since. No parts were replaced, so the homeowner avoided the board cost they had feared.

What this case teaches us

An error that started after nearby work usually traces to the wiring

An E1 communication error means the indoor and outdoor units cannot talk. The board itself is often fine; the link between them is the first thing to check.
An error that comes and goes points to a loose or shifting connection, not a dead part. A failed board would fault steadily, not for hours at a time.
Note when the trouble began and what changed nearby. Drilling, renovation, or any work in a shared ceiling void can nick a cable and cause faults that look far worse.

Questions this case answers

Aircon started faulting after renovation next door: what should be checked?

The cable route, before any component. Work in a shared ceiling void can nick a communication cable, and the timing did most of the talking here. Tracing the run turned up damaged insulation exactly where the cable crossed the drilling path, with bare copper resting against a length of metal trunking.

Can drilling in a shared ceiling damage an aircon cable?

It can, and the damage is often partial rather than a clean break. This cable still read good continuity while it sat still, which is why a plain end to end test would have passed it. Only the physical trace showed the nick. Heat shrink and cable ties holding it clear of the trunking fixed it.

Is an intermittent E1 different from a steady one?

Very. A truly dead board faults constantly, not for hours of normal running followed by a fault. This unit ran fine in stretches, which pointed at something that moves. Whether the bare copper touched the trunking depended on where the cable happened to sit, so vibration and heat decided when the error appeared.

Should I photograph the damage if work next door caused it?

Worth doing before anything is repaired. We suggested it here so the owner held a record if they chose to raise it with the party that carried out the renovation. Both control boards, the wiring elsewhere and the rest of the unit were undamaged, so the whole fault was one nicked cable.

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