generally your household insurance will cover you for public liability (legal liability as the owner of the building for accidents which happen during the period of insurance) but not for someone you employ or a member of your household. You should check the exact wording of your policy for coverage. It covers an accident involving friends, family (who do not live in the house) or anyone who calls to your property who may get injuried.
A prime example is injury as a result of scalding tea falling on a neighbours child in your kitchen.
Anyone you employ is not covered and they should have their own insurance in order for protection