We came out today because the customer had concerns about his detached garage having power loss. After an agree to the diagnosis we found that in the sub-panel located in the basement has a 30 amp feed going to the garage. The wire is a UF multiwire branch circuit. This wire is then fed under ground and goes to a 60 amp non fused disconnect on the left side of the garage then goes sub-panel in the garage. The garage has a Tesla wall charger installed on the left hand side. The Tesla has a 30 amp breaker and a 10/3 UF wire feeding it. After removing then disconnects cover I tried to pull the fuse out and it was welded. The wires are also burnt up as well. The customer stated that he has the unit set for 30 amp draw which could resulted in the burn or this was due to loose connections. For today we replaced the disconnect with a new one and informed the homeowner to set the charging between 15 or 20 amps. The sub- panel in the garage has (3) breakers that are not approved for the manu