u/Durzel

Hi

We have a setup here where there is an external utility room, and an outbuilding. There are 3 consumer units involved, all different makes. The house CU feeds the utility room via an RCCB protected MCB. The utility room has another MCB which feeds the outbuilding CU, but no RCCB protection. Finally, the outbuilding CU has its own RCCB protecting the socket MCBs.

We are having issues with nuisance trips, which seem to happen completely at random, but usually when something powerful is either plugged in or turned on. The induction oven (which is on the other side of the House CU board??) does it reasonably consistently, but it has been known to happen when powerful laptop chargers are plugged in - anywhere in the house.

My working theory is that the issue is an accumulated earth leakage across everything hanging off the "Boiler Room" MCB. The utility room has a washing machine, tumble dryer and two fridge freezers. The outbuilding has a number of computers and other electronics plugged in.

What usually happens is that the RCCB on the house CU will trip. When this is reset (and not before) the outbuilding CU RCCB will trip. When this one is reset, sometimes the house CU RCCB will trip again. This can happen a few times until randomly it will allow both to be reset. I have been taking to flipping the entire outbuilding CU red switch off before resetting the RCCB.

Here are the three CUs involved (MCBs feeding utility room and outbuilding marked with a red box):

House:

https://preview.redd.it/0wsjop60o35h1.jpg?width=1483&format=pjpg&auto=webp&s=0e8d9bb119d106ed13af54020b72bfb76068fb2b

Utility Room:

https://preview.redd.it/g3koxcf1o35h1.jpg?width=1089&format=pjpg&auto=webp&s=3340c003763c58c44a723397e19da9f68e2a8b32

Outbuildings:

https://preview.redd.it/qjofi3b2o35h1.jpg?width=1432&format=pjpg&auto=webp&s=a63141363946779fa9fa76695876ff8fed148e07

The electricians I have spoken to so far basically either don't have any time to fix it, or won't do anything except quote to replace absolutely everything - all three CUs, and RCBOs throughout. They have said it is not worth in labour terms to try to localise the problem.

I am looking for any solution really that might alleviate the problem.

I did some light reading (a little knowledge is a dangerous thing) and it was suggested to me that one could replace the MCB in the Utility Room with a RCBO instead - specifically this one: https://www.screwfix.com/p/wylex-20a-30ma-type-a-sp-c-curve-rcbo/56060 - with the idea being to separate the earth leakage of the utility room from the outbuilding?

To be clear - I'm NOT looking to do any of this myself, for obvious reasons. I will pay a professional to do it. I am hoping to get some general opinions on what options I have to resolve this, or hopefully minimise it. I'm looking for a cost-effective solution, if possible.

Thanks in advance.

Upgraded my Commander to 6.4.5 earlier, which promised faster Bluetooth connectivity to it, etc.

Since then, I am unable to turn on SMT support. As soon as I toggle “ScanMyTesla support” on, the app changes to “Connecting” and never connects. At this point the Commander is technically soft-bricked, since it seems toggling that option breaks connectivity. The S3XY_OBD access point becomes visible but you can’t connect to it.

At the point the only thing I can do is unplug the Commander for several seconds, or let the car sleep, at which point I can connect again. If the Commander was installed in the MCU rather than behind the centre console this would be a painful process.

Has something been added in this firmware which has broken SMT support? Any way for me to revert to 6.4.2 firmware, which worked fine? SMT support is an important feature for me, as I’m monitoring a dying HV battery.

Thanks in advance.