Good question, as it never made sense that a 50 amp connector would be used when our circuit breaker is 120 amps. I'll include the obligatory link to
190's melted connector.
However, the SB120 is very large and heavy (it's about twice the size of the current FIRST conector, the SB50). You might want to go for something in between, such as the SBO or the SBE80.