If a carer starts showing symptoms whilst in a customers home they should inform the family immediately and discuss if alternative arrangements can be made for care.
Guidance says that if you live with a vulnerable person you should try to find somewhere else for them to stay for 14 days so therefore if suitable the carer should leave the customers home to follow the self isolation guidance.
If they are unable to leave the clients home then they should self isolate as much as possible whilst other arrangements are being made, reducing contact as much as possible and following guidance on self-isolating with someone experiencing symptoms here.