[allroundernaman]

#include <amxmodx>

#if !defined MAX_PLAYERS
const MAX_PLAYERS = 32
#endif

const FRAG_LIMIT = 10
const ADMIN_FLAG = ADMIN_LEVEL_G

// Modify the ban command to your needs
// Default: amx_ban <minutes> <userid> <reason>
#define BAN_COMMAND "amx_ban 180 #%i ^"Frag Limit Over^""

new g_iFrags[MAX_PLAYERS + 1]

public plugin_init()
{
    register_plugin("Frag Limit Ban", "1.1", "OciXCrom")
    register_event("DeathMsg", "OnPlayerKilled", "a")
}

public client_putinserver(id)
{
    g_iFrags[id] = 0
}

public OnPlayerKilled()
{
    new iAttacker = read_data(1)

    if(is_user_connected(iAttacker) && iAttacker != read_data(2) && !(get_user_flags(iAttacker) & ADMIN_FLAG))
    {
        if(++g_iFrags[iAttacker] == FRAG_LIMIT)
        {
            server_cmd(BAN_COMMAND, get_user_userid(iAttacker))
        }
    }
}

Here's the code I am using.