Hi @Ludit1 

Welcome to the Sonos Community!

Sorry to hear of the issue you’re having with your Amp! Amp will indeed protect it’s circuits when it detects an improper load, but it typically does so by ramping the volume down to 15%, rather than stopping completely. I just now noticed that you submitted a diagnostic a few days ago - it confirms that there is an Amp Fault, so the Amp is indeed trying to protect itself.

If you are unable to replicate getting back to 100 when the left wires are disconnected, as you are with the right, then it certainly seems like either the right speakers or the right cabling is at fault. If the fault’s manifestation definitely coincided with getting work done on your property, it is certainly tempting to lay blame there. My suspicion would be that the cable got crushed to the point where the cable’s insulation is no longer keeping the two wires isolated from each other.

It will likely be a lot of work, but the only way to be sure would be to connect the same 4 speakers to Amp using different wires (or one different wire at a time) in a temporary setup and testing. It may be easier in the long run, however, just to get the entire right cable replaced in the first instance; although it’s not impossible that the speakers are at fault, it seems far less likely to me. If you have access to the cable run, a visual inspection of the entire length of cable - especially near where the electricians were working - should reveal the problem.

I hope this helps.

Edit: If you have a multi-meter, test the resistance between the two wires on the right cable - it should come out as between 4-8 Ohms. Anything lower will overload the Amp.