Get some fusion coils (all of the fusion coils you can get on any map) go to forge and stack (carefully) them.

In the middle of fusion coils and plasma boxes (the covenant fusion coil ) put a trip mine in the middle or on the sides, then set off the bomb in the middle of the map.

On Sandtrap that has alot of fusion coils, after placing the mines around the bomb shoot it with a sniper rifle.

Why with a sniper rifle? Only because the bomb will kill anyone withing 100 meters or more!