The photo above depicts a spa control box that was damaged by poor water chemistry management and improper electrical installation.
Since the spa was not supported by a local dealer, the customer made the first mistake on their own. The homeowner ran the electrical directly to a 50 amp breaker which was not GFCI protected. The second mistake was on the spa retailer (an inventory liquidator who blew into town for one week.), as the orientation was either incomplete or incorrect- The customer insisted that they did exactly as they were directed to do. The water was not only acidic, but soft- having very little mineral content.
Once the heater seals had failed, water was able to leak onto live heater terminals- causing burning and arcing. This would have tripped a GFCI (ground fault circuit interupter) had there been one installed.
The subsequent service call was not covered by the warranty, even though the spa was less than 9 months old. As far as I know, the spa is still sitting in the same condition as I left it- the spa owner unwilling to pay for repair on the damaged control box or to rectify the unsafe electrical circuit.