You shouldn't; in essence, none should use such an electric kettle containing plastics. When plastics come in contact with heat, it releases poisonous chemicals like BPA. According to research, consuming a huge amount of BPA can lead to various health problems. It can affect the hormone levels in the blood, and even it can affect reproductive organs. Anyway, if you choose any tea kettle featuring plastics, ensure that it is BPA free. Plus, make sure while boiling water, plastics shouldn't come in contact with heat.