If you're dealing with IEC equipment you could try Moeller (now Eaton)'s Curve Select. It's a very fancy Excel Sheet that prints time-current curves based on fuse sizes and breaker settings. It's a free download, but you do need to register with them:
http://www.moeller.net/en/products_solutions/power_distribution/power_communication/curve_program/index.jsp
It has a few limitations for doing an arc flash study, most notably:
- Only Moeller equipment available, be very careful with comparing breaker settings in the software and those in your system.
- No clearing times or tolerances built in, so be conservative with your time estimates.
- No easy way of displaying your calculated arcing currents to determine breaking time.
To get anything better you would have to move to commercial software packages, but they're obviously far from free.
Boa sorte
