How to use 1/0 gauge grommets

[AndrewHD 10+ year member]

Hey guys I just ordered these to go in my firewall. Scosche WPG0 10 10 Pack of 0 Gauge Waterproof Grommets | eBay

This is a stupid question but what way do they install? With the round dome on the firewall's side or the dome on the inside of the cabin?

Click to read more...

 

[AndrewHD 10+ year member]

Also what size drill bit should I use?

 

[bbeljefe]

The round dome is a nut with a compression ring in it and it should be on the side where it will be exposed to the elements. As for hole size, you'd have to look at the data sheet that comes with them or measure the threaded shaft.