[Milsurplus] 28V Relay Question

[Richard Brunner]

Contacts do indeed have different ratings for ac and dc.  The reason is
that with ac there are two current zeros per cycle, and ac arcs tend to
be self-extinguishing below about 200 volts.  DC arcs must be extended
until they are cool enough to self-extinguish, which might be a mighty
long arc.  It is not unusual to have the ac rating 20 times the dc
rating.

Richard, AA1P