This "smart" adapter allows you to combine two 30 amp power post outlets into a single 50 amp for the boat 50 amp cable. It will automatically shut down if reverse polarity is sensed. See it at http://www.marine-electronics-unlimited.com/Hubbell+YQ+230+Adapter.html We used it only one time, in NC. The Marina manager insisted there was no reverse polarity in the pole we were to use. However, once I demonstrated the breaker kicking on that pole, but not another one, he decided he might indeed have a problem. No burning or scorching and in nearly new condition. Photos available. MSRP is $750. Web prices run around $300. First $200 takes it. Don Young Vero Beach, FL. 772-569-5456