Trumpy, The PSCC is going to depend on a few factors and I am not trying to sidestep the question. Cells can explode due to a number of factors and I will list a few. Electrolyte to low in the cell which allows gasses to come in contact with conductors that could short or arc when heavy currents cause them to melt. Acummulated gas in a cell which is ignited from an internal falure such as a weld breaking loose from rough handling or improper fastener installation. Equipment failure causing over charging which causes excessive gasing and an external spark or flame.
Lead acid cells from different manufacturers have a varying internal resistance which is the limiting factor in a PSCC, deep cycle, SLI, VRLA, they are all different. One can determine this by the formula RB = (EB - VL) / IL. Or, battery resistance = (open circuit battery voltage - specified loaded voltage)/ load current. The short circuit current (PSCC) is computed by the equation Isc = EB / RB = EBIL / (EB - VL).
One point also to remember is the limiting circuit conductors. Many stationary systems are now using a type of cable limiter to prevent catastrophic breakdowns in wiring and insulation in case of a short circuit.
Comparing this to an AC circuit is difficult because the AC supply doesn't diminish over time as does the battery voltage even though the instantaneous currents maybe higher for a given voltage. Also the AC supply has ocpd's in in each branch.
Your question " And for an even sillier question, what is the best type of protection to use with a DC battery installation". Could best be answered by saying "As much as you can work safely in". I personally have a heavy leather apron, long gloves with leather protectors, glasses with restraints, face/head shield, insulated tools, heavy blanket for covering nearby cells and a insulating shield for working inside live panels. I personally have had primary cells explode in my face without any injuries because of what I wear. One thing to remember is never trust what the other guy did or says, if you do this usually ends up with an accident. I usually look over the installation thoroughly and try and determine what looks good and what doesn't and work backward to make everything as safe as possible. There are as many ideas about how cells should be maintained as there are about wiring a house. Also the mechanical framework and structure to support the cells should not be overlooked. Sorry if I got a little long winded but some times there just isn't a short answer.
