In the level pack i'm making (The abandoned station) I wish to add sparks to simulate arcing wires.

I'm thinking that narrows it down to the two shield bolts (Plasma and fire). The fire bolts would look the part, but the plasma bolts would have the sound effect.

I'd like to get a generator of a shield bolt (That will work in SP) so it will hit a hidden wall, showering the intended area with sparks. That possible?

Put a generator on a revert morph event. But you could also use an electroblaster turret: Put a generator on an Area Fly Off.

Create generator on these events to get the desired shield shots.
Revert morph = Plasma shield
End area = Fire shield

You could also make a bomb crate with 15 extra events set to one of these two. This will make lots of sparks fly out when the crates are broken.

I only get the regeneration sparkle, but no bolts. Does it only work for multiplayer? Am I doing somthing wrong?

You're doing nothing wrong. The problem is that these things are fairly inconsistent. As far as I know the only shots you can get to spawn reliably 100% of the time are seekers, electro blasters, and TNT. Everything else will show up occasionally, but usually will produce nothing. Using a crate like overlord suggested will produce a more consistent result, but obviously is limited in terms of usefulness.

You could hide a couple of electro blaster events, then hide an ambient sound event to make the plasma bolt sound.

My contribution.
This is by no means perfect, as it involves the rather cumbersome crates, so you'll always want it hidden behind walls, but it does provide reliable sparks. There isn't a constant flow, as that seemed a little extreme, but I'd imagine more constancy could be worked in with a little effort.

Instructions for Modification:

• The apparatus is four tiles wide by two tiles high. For ease of description, events will be referred to as in tiles 0;0-3;1.
• To modify the number of shield blasts contained within each crate, modify the Delay parameter, currently set to 15, on events 0;1 and 1;1. Hypothetically 1;1 will represent the number of blasts when the level begins, and 0;1 will be subsequent blasts, but JJ2 isn't precise like that, so don't count on it.
• To change the shield blast to plasma instead of fire, modify the Event parameter, currently set to 17, on events 0;1 and 1;1 to 19. Or, really, any number at all for any event at all, but this is just for shield blasts.
• To change the generation rate of the blasts, modify the Delay parameter of 3;1.
• If you'd rather not use a bomb crate because of its explosion, replace the Event parameter of event 3;0 with 46 (gun crate), 47 (carrot crate), or 48 (1up crate) instead. Just keep in mind that this will introduce objects into the level that won't disappear after a few seconds, and could quickly take up a lot of memory/speed.
• If you see a lot of DON'T USE events, replace event 255 in your jcs.ini with the following:

  255=MCE Event                      |+|Area      |MCE    |Event  |Event:8|Delay (secs):5

• The generating fly off (electro-blaster) and disappearing/reappearing stomp blocks represent just one way of making the crates repeatedly open. You may certainly replace them with anything that is more appropriate to your level's needs; please be sure to place event 1;1 at the tile the crate will open at.
• Obviously, since it is a small apparatus, you can put it anywhere you want in the level, many times. Just keep in mind that it can use a lot of sprites and you may start seeing your character and other things disappear, which is a good reason to limit the number of blasts contained in each crate...

Let me know if you have any other questions. I hope this is clear and useful.

Maybe say what each of the events does, I'm just wondering ;p

Basically, 2;0 is instantly moved to 3;0 by 2;1, where it creates E:3;0 every P:3;0. This E:3;0 is moved instantly by 3;1 to about 1;0. E:3;0 falls down at least one tile into 1;1, and is destroyed either by tile 1;1 or 0;1 regenerating each D:0;1. E:3;0 appears over either 1;0 or 1;1 and creates D:1;x copies of E:1;x upon destruction.

An image or two could help clarify things.

Lol. With JCS next to that post I managed to understand it ;p but that post looks insane without 'visual resources' ;p

An image, yes, or an article, but I was sitting in German class waiting for the teacher to show up, so I didn't have the time. Someday an article will materialize...

Puffie, does it help?

Oh yeah. that spark machine looks like the thing I need. I'll play with it on the level, and see if I can get it to fit.

One thing I did try is the electroblaster turret, masked along the ceiling. It has a nice effect, if a little obscure.