I have a second 30A cord that I have to connect to the main line about 50% of the time - because, like your case, the pedestal is too far from the trailer. I've found the connection to be very secure & watertight. Nevertheless, I always put a couple of wraps of Saran Wrap around it. It helps keep the lines from pulling apart if someone trips over one of them. And if it happens to rain, it's just a little insurance against water intrusion. An ounce of prevention, and all.
2013 Eagle 266RKS
2011 Ford F-150 w/3.5L Ecoboost & H.D. Tow Package