RCCB triggered by AC. And then not anymore. Any suggestions?

[OneMoreFarang]

The ACs in my new renovated condominium are since about a year in constant use. 99% of the time they all work fine.

One night a few days ago suddenly one of the ACs had no power anymore. I checked the breakers (RCCB and MCB) and the RCCB was off. When I switched it on again it triggered again within a second. I switched off all other MCBs which are connected to that RCCB, and it became clear that the AC (or cabling or connections to that AC) is the problem.

I decided to check the problem the next day. I switched everything on again and it worked. And until now, a few days later, there was no problem again.

 

I called already Daikin to clean the ACs. I guess if they see an obvious problem, they will let me know.

I also looked at the cables and connections. From what I can see there are no problems anywhere.

I suspect that maybe some insect created a shortcut, and this triggered the RCCB.

 

Do you have similar experience or an educated guess about the problem?

 

P.S.: I learned how to do electrical installations in Europe, and I made the electrical installation in my Condo. All has earth and RCCBs and MCBs or RCBOs. It is extreme unlikely that there is a problem with the cabling or connections.

 

 

[degrub]

Any spots for water intrusion , even just condensation from moist air on cold parts , into conduit , onto power boards, or at connections?  Immediate trip after reset suggests a path to earth or metal housing.

 

Other possibility might be a deadheaded compressor , failing compressor rotor bearing causing sustained high starting current, or a fried gecko ?

[OneMoreFarang]

1 minute ago, degrub said:

Any spots for water intrusion , even just condensation from moist air on cold parts , into conduit , onto power boards, or at connections?  Immediate trip after reset suggests a path to earth or metal housing.

 

Other possibility might be a deadheaded compressor , failing compressor rotor bearing causing sustained high starting current, or a fried gecko ?

 

Thanks for your reply. It could be any of above. But the triggering of the RCCB happened within a year only one time. If moisture would be the problem, then I guess that would likely happen more often.

Maybe it is a (now) fried gecko. Let's see what the AC cleaning process will bring up.

[bluejets]

One must remember not to dismiss the breaker itself.

There are different rating such as type a,  type c.

Also brand can sometimes catch one out.

External noise, interference, load changes can and do cause, for the most part, unexplained tripping.

Fortunately for us, we have access to line analyser test gear to verify or other probably 95%.

Just saying........