I am looking for rules for sizing cables for short pulses. For example, if I were to run 2000A DC current for 0.5 seconds in a cable, what size would I need? Sizing as if it were continuous current seems like overkill. I could calculate the temperature rise for each wire size and then pick one, but how do I determine an acceptable change in temperature?
If you plan on 2kA for 0.5 s, you may want to limit the temp rise to the temperature rise of 80'C
4/0 copper cable D = 11.7 mm Area = 107 mm² 0.1608 mΩ/m
- Fusing current in 10 seconds = 3200 A
But if were computing the short circuit capacity of wire rated before fusing open, this was done by the Southern California Edison Company published in June 1928 .
You know the temperature rise just like every other wire...Max Insulation Temp - Maximum Ambient Temp.
Calculating temperature rise due to pulses would require things like thermal impedance if you go with the physical models and those are basically simulations. 2000A is a lot of current so will produce a lot of resistive voltage drop in your wire so try this first instead...it's much easier:
- Determine your allowable voltage drop.
- Determine the resistance required to achieve this.
- Find an AWG with this resistance.
- Check a standard table to see if that AWG can't already support 2000A continuously. If it can, you're done (although it still might be tough to find a table with AWGs that can go up to 2000A).