Charging of a manned maneuvering unit in the Shuttle wake

The Manned Maneuvering Unit can charge to about -1400 volts in the wake of the Shuttle as an oxygen ion plasma. One percent hydrogen would lower the potentials by 14%, and 6% hydrogen would reduce the potential by a factor of two. The presence of a higher percentage of hydrogen ions at higher altitudes would substantially decrease the maximum potential. Is a potential of 1400 volts hazardous to the man in the Manned Maneuvering Unit? Perhaps a spark will occur when the unit touches the Shuttle. This potential, if sufficiently nonuniform on the MMU surface, may produce a surface discharge. Radiation from these arcs may be harmful to electronics in the vicinity and therefore affect the MMU mission.