Matt e Tripping

[Adopado]

I must admit I’ve never had an RCD running at 100% rating for 5 or 6 hours.

It's not just an RCD. An RCD does not measure overcurrent. An RCD doesn't trip due to overcurrent. What you are describing is probably an RCBO which has the function of an RCD combined with an overcurrent circuit breaker. An RCBO can be tripped either by an RCD fault or by an overcurrent issue. Some installers fit 32 amp breakers and some fit 40 amp breakers. The Matt-e is for earthing fault issues. Overcurrent trips are a separate problem.

 

[qwickshot]

If a 32A MCB is tripping when used at 32A, it’s faulty. That’s not the expected behaviour, it should be able to supply 32A continuously.

 

[thewishy]

My wallbox is fitted with
- Hager 32a "C Curve" MCB
- Garo 40a DP RCBO in a separate box (Hager don't do a single width DP RCBO, and want a fortune for the double width. Wallbox fit PEN fault protection, but not a DP RCD)

32a "C Curve" is what wallbox specify in the install adjustments. I suspect the installer might have used just the 40a RCBO on Henley blocks otherwise... I guess they don't want a callback if the MCB/RCBO from the cheapest supplier is poorly calibrated.

Anyway, never a trip on the 32a MCB. This sort of overcurrent protection is just a bimetallic strip calibrated to trip at a specified point above the rating, not some sort of sensitive flower which needs to left some headroom.