I gather your RV has a maximum rating of 30 amps; so plugging it into a more powerful circuit (50 amp) will not make it draw more power than it is designed to do. That said, most every 50 amp shore power outlet post that I have come across has both a 30 amp and 50 amp outlet on it; so just plug in a normal. If the post only has a 50 amp outlet, you will need a male 50 amp to female 30 amp adapter (Camping World, Amazon, etc.) which you would plug in first. Then plug in your surge suppressor and then the RV power cord as normal. No harm to the surge suppressor or your RV, they will only draw the 30 amps required, no more.
D_B Travelers - 30 nights in 2016... so far. 54 nights in 2015. 2014 Rockwood Windjammer 3001W Diamond Pkg, 2015 GMC 3500HD CC DRW Duramax, Equalizer 14K hitch, TST 507rv TPMS.
"Happiness? A good meal, a good cigar and a good woman - or a bad woman; it depends on how much happiness you can handle."
George Burns (1896 – 1996)