TNTPrimed not acting as it should.

I'm trying to make it so in my plugin when a player places a block of TNT it will spawn a TNTPrimed entity instead however, through testing this TNTPrimed isn't hurting players like TNT traditionally does when I light it with a redstone torch. Any ideas as to why?

This test plugin is the only plugin I have installed. Here's the code to my event listener:

Code:

        @EventHandler
        public void TNTPlaced(BlockPlaceEvent evt) {
                if(evt.getBlock().getTypeId() == 46) {
                  evt.getBlock().setType(Material.AIR);
                  Entity tnt = evt.getPlayer().getWorld().spawn(evt.getBlock().getLocation(), TNTPrimed.class);
                  ((TNTPrimed)tnt).setFuseTicks(20*3);
            }
}

When I say not hurting players I mean something like this, I can stand in the middle of the TNTPrimed entity and I'll only take 4 hearts damage, but with traditionally lit TNT I will die.