Electricity and Conductivity


Rules Questions


has anyobody got any idea how to rule electrical effects that are used on a conductive medium, say a metal-clad floor or salt water? how could targets be affected (full or fractional strength) and what area (or space) could reasonably be affected?


Darth_Slanderous wrote:

has anyobody got any idea how to rule electrical effects that are used on a conductive medium, say a metal-clad floor or salt water? how could targets be affected (full or fractional strength) and what area (or space) could reasonably be affected?

There are no rules for it. The game does not really account for physics as we know it. A GM would have to make rulings as he saw fit if he wanted to make up new rules for such things.


I recall an old 2E article that discussed electricity and conductivity. It basically suggested treating the electricity as being an area burst type of effect. So, for a metal floor, the electricity would burst in a circle on the floor. For something like Shocking Grasp, maybe in a 10 Feet diameter burst around the caster. For something like Lightning Bolt, think the entire floor. In water, treat it like a Ball, say a 5x5x5 cube or in the case of Lighting Bolt, say a sphere with a 20 feet radius. Also, in water, I might impose a -2 penalty to saves. YMMV


Yeah, per RAW nothing special happens and you can rule that magical electricity isn't regular electricity, myself I houserule 50% damage inflicted to people touching water/metal, reflex save negates for metal floors etc, +4 to the DC per 6"'s of water being stood in if standing in water.


Closest thing you'll find is that Shocking Grasp grants a +3 attack bonus to creatures in metal armor. I don't really see metal causing the electricity to do more damage. If the effect is instantaneous, you're either shocked or you're not. But it would definitely increase the chance of being struck (penalties to Reflex saves, bonuses to trap attack rolls).


I once looked this up for an underwater encounter with a giant eel and a party with a sorcerer with lightning bolt.

In conclusion, it depends on the water's salinity. The current travels through the better conductor. In salt water the water's conductivity is greater than the body's and thus the effect on a person would be minimal as the current would only travel along a body's surface.
In freshwater the the conductivity of a body is better than the water's so the current would travel towards the better conductor.
In brak water the conductivity of the water and a body are almost equal.

The encounter took place in an estuary (brak water) so I ruled that the Lightning bolt would in fact emanate as a burst from the caster's fingertip affecting all inside the area.

I admit some official ruling on underwater spell effects would be good to have. Another case where rules and RL physics don't match well.


ok, thanks a lot. that's been quite helpful.
you all have a nice weekend :)

Liberty's Edge

The Electricity Energy Damage Type is not electricity as we know it in the real world. It really isn't even similar. Don't expect it to act like real electricity.
-Kle.


There was a 3rd edition adventure that had a lightning trap do, I think, half damage to anyone in the pool of water that it was in. The pool was only about 15-20 ft wide and ankle deep.


What kind of electricity is it then? Source?
Fire damage seems fairly real world to me...


Simcha wrote:

What kind of electricity is it then? Source?

Fire damage seems fairly real world to me...

except that unless its sustained it doesn't catch things on fire at all not even dry kindling covered in oil. you scorching ray that you get nothing. Flaming sphere however different story.


Talonhawke wrote:


except that unless its sustained it doesn't catch things on fire at all not even dry kindling covered in oil. you scorching ray that you get nothing. Flaming sphere however different story.

You mean like fireball-like explosions that do not necessarily ignite stuff IRL?

Oil doesn't burn btw, the fumes do.

But I agree, the physical effects of many elemental spells are unsatisfactorily vague.


there is a section in the dragons revisited PF book that talks about Bronze dragons that lined their lairs with copper pipes so they could electrocute trespassers from anywhere in the lair, that at least implies that electricity is conducted in a damaging fashion.


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Simcha wrote:
Talonhawke wrote:


except that unless its sustained it doesn't catch things on fire at all not even dry kindling covered in oil. you scorching ray that you get nothing. Flaming sphere however different story.

You mean like fireball-like explosions that do not necessarily ignite stuff IRL?

Oil doesn't burn btw, the fumes do.

But I agree, the physical effects of many elemental spells are unsatisfactorily vague.

Fireball specifically calls out that flamable objects may ignite in it's area.

PRD wrote:


The fireball sets fire to combustibles and damages objects in the area. It can melt metals with low melting points, such as lead, gold, copper, silver, and bronze. If the damage caused to an interposing barrier shatters or breaks through it, the fireball may continue beyond the barrier if the area permits; otherwise it stops at the barrier just as any other spell effect does.

The problem is, of course, that the game devs have never sat down and wrote the rules for elemental effects. There's no rules that say a spell with [fire] subtype can start fires. There's no rules that say a spell with [shock] subtype gains a bonus to hit for metal clad or turns into an area effect (or doubles it's area effect) around conductors.

So we're left with bits and pieces scattered throughout like the fireball entry, where it specifically calls out it starts fires and melts gold (btw: How many people actually do that? In game, have the fireball melt the PCs coins when they get hit?).


Tell me this isn't about bringing physics into casting a spell?

Correct me if I'm wrong, but assuming someone could actually summon the electrical energy to cast a lightning bolt in the real world then apply physics to the charge... wouldn't it simply earth off either into the ground directly in front of the caster or earth off THROUGH the caster and subject himself to his own lightning bolt? And be completely beyond his control in where it chooses to earth so saying 'go forth and smite THAT one' is completely out of the question.

That implies that there is a certain amount of magical force that is in fact preventing this from happening overruling normal physics rules. Given that normal physics (which has just been told to go sit in the corner) is what dictates that it should do X or Y in contact with an element that has a suitable level of conductivity, how do you wake physics up without him being angry about the whole corner thing?

Unless you think that your lightning bolts to be self earthing... Completely up to you of course!

Sorry... I had to get that out of my system.

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