how to run cable through firewall

I have a 1/0 gauge cable I need to run through the fire wall on my 02 impala. Dose any one have any tips on drilling through the firewall. Is their anything I need to look out for? I have the grommet, is their a special drill bit I need?

hi i have run the same size wire through my firewall.  First  you should see if there is a factory grommet that you can use to run the wire through but it being of that gauge not likely but never hurts to look.  So if left with the option of drilling. MAKE SURE OF WHATS ON THE OTHER SIDE BEFORE YOU DRILL. you don't want to drill through anything other than the metal.  You need to get a drill with a metal bit.  Word of advice hold onto the drill tightly with both hands.  When the drill bit starts to break through to the other side the bit might catch on the metal thus causing the the bit to stop and the drill spin out of your hands.  Could break a wrist if you have a very powerful drill! The best way to avoid this happening is start off small and increase the size of the hole gradually using different drill bit sizes. then use a a drimmel tool or something to that effect to smooth out the edges of the hole.