Opened a VISTA STT 900 and found the secondary wires from the trans to the 3 breakers in pretty bad shape - corrosion, melted insulation, one wire completely melted. The wires are 12AWG rated to 600V - I'm assuming low voltage wires. Can I replace them with regular 10AWG also reated for 600 V that I got from home depot as high voltage wires ?? isn't better wire since it is rated for high voltage power versus what vista seem to have installed low voltage wires knowing that on the secondary it is low voltage anyways ??? The other question, what could have caused this mess ?? had the Transformer for 4 years with 270 W at each circuit without any problems. I moved to a new place and and went to 290W for each of the 3 circuits....I know I should have stayed 10% of max capacity...but could this extra 20W on each circuit created this nightmare eventhough i'm still below the 300W threshold and this is a vista not a cheap transformer ?? Thanks.