Could 48V arc across this small gap?
Even a very small gap is sufficient to stop quite a bit of voltage. IPC-2221B would specify 0.6mm for 48V for an exposed gap on a PCB. 

Breakdown voltage of an air gap is much higher than that-- 48V will hardly start an arc over any non-microscopic gap. 

Of course if you get conductive dirt or liquid on it, all bets are off. For example, by using plumber's solder with acid flux.