IndustrialCraft 2

IndustrialCraft 2 is a classic among tech mods. It brings electricity into the game: the player builds a generator, runs cables, connects machines, and starts processing raw materials on a large scale. Ore can be crushed, washed, and enriched so that it yields more metal than ordinary smelting would.

For many players, IC2 is the first tech mod they ever encountered — and on servers with version 1.12.2 and older, it is still used today. You'll find it on just such servers in our list.

The foundation is energy (EU) and three voltage tiers. The player starts at low voltage (LV), gradually moves to medium (MV), and high (HV). If they connect a machine to a higher voltage than it is built for, the machine explodes — and that is exactly the thing players discover for themselves, usually with a big bang.

IC2 belongs on both sides: on the server, so that machines and ores exist, and on the players' side, so they can see them and build. On a modded server, this means players must install the same version of the setup.

For operators, it is important that IC2 also supports nuclear power. It is safe when wired correctly, but if there is a mistake, it causes serious explosions. On a public server, it pays to have backups of the world and to know that players at nuclear reactors will occasionally make a hole — it is part of the game, not a bug in the mod.

1. IC2 belongs on the server and with the players — the same version on both sides for the same game version.
2. Determine the server loader (Forge for older versions) and download IC2 from the author's official site (the link is on the mod card).
3. Stop the server and make a backup of the world — the mod adds ores that generate into new chunks.
4. Upload the .jar to the mods folder on the server; players do the same on their end.
5. Start the server and check the console that the mod loaded without error.
6. Join and verify that you find ores in new areas (tin, copper, uranium) — they will not be added to already explored areas.
7. Test the basic chain: generator, cable, electric furnace. Verify that the machine actually runs.
8. Explain the voltage tiers to players (LV, MV, HV) — connecting a machine to a higher voltage will destroy it in an explosion.
9. Check that players see other players' machines correctly (without the mod they would see nonsensical blocks).
10. With nuclear reactors, expect players to occasionally cause an explosion; back up the world more often.
11. When updating the game, verify that IC2 exists for the new version — the classic version remains on 1.12.2.

IC2 is a classic mod for 1.12.2 and older. Before you deploy it on a newer server, verify that a version exists for your game.
It belongs on both sides. Without the mod on the players' side, machines appear as nonsensical blocks and the player can't build anything.
It adds ores to new chunks. It won't be added to an already explored world — when needed, this is solved with a new world or by generating new chunks.
Voltage tiers are the most common source of explosions. Write in the guide for players what goes with what; you'll save questions and holes in bases.
Nuclear power can cause a big explosion. On a public server, back up more often and know that it's part of the game.
Watch the load: large factories with many machines can slow the server down. When players report lag, look there first.