"I use 2 30 amp drop cords and an adapter to go from the outlet on the home to the EMS"
I hope they truly are GOOD 30 amp extension cords. One of the resident electricians can explain the theory of loosing "power" the longer the run is. Especially with inferior extensions.
Melting is caused by heat.
Heat is caused by resistence.
Two common ways to produce resistence are: overloading or a loose connection.
Assuming you are NOT overloading, and the extensions are of sufficient guage to handle the load over the legnth of run you describe, I would look to make sure you have a tight connection between the male/female plugs.
Then again...me twuck driber, and only part time handi-dude---- not electro dude.