Chilli Jr - excessive earth leakage current, potential safety issue

kgallen · 2026-08-17T13:33:21Z

Information for users (if anyone still cares!).

I recently purchased (2nd hand) two Chilli Jr dimmers for an install at a local voluntary art space.

As is my usual approach, I always inspect, refurbish and electrically test equipment before I deploy it.

On one of the Chilli Jr dimmers I purchased I observed an unusually high earth leakage current compared to the other Chilli Jr dimmer, when testing with my Megger PAT tester. Around 5mA compared to the <1mA observed on the other (#2) Chilli Jr dimmer.

I've tracked this down to the fitting of incorrect EMI capacitors at some locations on the phase trigger PCB. There is no evidence of any rework or repair on this board, so this looks like a factory pick/assembly error. These capacitors are used (correctly) elsewhere on the same PCB.

The phase trigger board takes the three mains phases (or three copies of single phase mains) and derives the zero-crossing trigger signals for the triacs. For EMI purposes, there are X2 and Y2 capacitors employed across the line, neutral and earth supply terminals.

- X2 capacitors are used line-neutral and fail short to trigger over-current protective devices.
- Y2 capacitors are used line-earth and neutral-earth and fail open circuit to avoid creating a shock hazard on the metal casing (since these dimmers are Class 1 devices).

I've found X2 class capacitors fitted where Y2 class capacitors should be fitted in one of the Chilli Jr dimmers.

Photos show 0.1uF (100nF) X2 EMI capacitors fitted where 0.01uF (10nF) Y2 EMI capacitors should be fitted.

As can be seen in the following photos, the X2 capacitors are grey, the Y2 capacitors are blue.

Incorrect X2 (grey) caps fitted N-E on all three phases. Correct Y2 (blue) caps fitted L-E on all three phases. Correct X2 (grey) caps fitted L-N on phases 2 and 3 (phase 1 has transformer isolation).