High Voltage Capacitor Discharge Cable?

[Pulseit]

I've been looking for a suitable cable to discharge a 5kv cap into objects for fun, but as far as I can see there is no high voltage, high amperage cable available anywhere?

[SeanB]

Regular neon sign cable not available, it generally is silicone wire insulated to at least 30kV and is 1mm copper, capable of carrying 10A continuous or a lot more in a pulse. Otherwise regular spark plug wire ( non resistive non inductive) will also do.

[Pulseit]

Its a 5kV 40uF pulse cap, at a guess it will be in the 1000A+ discharge range. I had assumed it would vapourise 1mm core wire, spark plug core wouldn't be any thicker would it?

I was thinking of something around 10mm core diameter.

[SeanB]

Not that much energy, the spark plug cable will handle it, along with the sign cable. One pulse per 30 seconds will allow time for the core to cool. 500J of energy will be a loud bang, you will want a sacrificial contact point for sure, preferably a tungsten one.

[FrankenPC]

Arc welding cable.  You can buy the stuff anywhere. 
Here's one that does 600V @ 600A 100% duty cycle.
http://www.wireandcabletogo.com/500-MCM-Welding-Cable-Class-K.html
 It's $10/ft.  You can probably find it a lot cheaper used.  Gang multiple cables in parallel to meet the 1000A/5000V requirement.   IMO 1000A at 5000V is pretty insane.   But it is very low duty cycle. 

Maybe buying solid copper bars and bolting them together would be a safer idea?