When charging phone from wall sockets, the phone charger may get very hot, which is not unusual. Except in rare situations, it is never hot enough to melt the plastic casing of the charger.
Chargers are generally designed to be durable but even the toughest charger needs to be protected from damage. One thing to bear in mind is that water is one of the common things that damages chargers. This may happen when charger is exposed to rain or falls into a bucket of water. It is common for phone users to buy phone case for protecting their phones without thinking about protecting their chargers.
There is also the solar powered charger which is becoming very popular in Kenya. The solar powered charger is powered by sunlight. It is efficient too. It is very effective in the rural areas where electricity is lacking.
What is a powerbank? It is a battery device for charging small devices using the USB ports. It does not provide the wattage that is enough for charging batteries for large devices like MacBook or laptop in Kenya. Power bank is usually portable and used to charge small devices without using main power source. It is easy to use and has two USB slot that has 5V - 2A which allows you to simultaneously charge two devices.
The power bank itself is charged by plugging it into wall sockets using adapters with USB cables or to USB port of tablets or computer or laptop. Charging the powerbank is faster through wall sockets than through tablets or computers. In many powerbank models, the power source must be on for charging to start. However, in newer models, charging starts automatically once it is plugged in.