Excess liability insurance is a type of coverage that offers additional protection exceeding the policy limits of a specific insurance policy that the insured has. It does not affect the duration or terms of the underlying policy; instead, it increases the policy limits of that specific policy.
It raises the limit of the coverage provided by existing insurance. The excess policy does not expand your current policy coverage. It just offers a higher policy limit to protect the business from damages where the claim exceeds the amount of the underlying policy.
The type of policy applies to one policy only. So, if you choose to add excess liability insurance to the general liability policy, the limit for that particular policy will be increased. This can certainly be beneficial for your business if you are operating in a risk-intensive industry.