First, the Risk Breakdown Structure is called RiBS, not RBS!
Now to be honest, rare are the projects and the project manager who use a Risk Breakdown Structure, personally, I don't see a huge benefit for it, as it is like stating the obvious.
While the Risk Breakdown Structure is similar to the WBS as they're both hierarchical charts, it is different when it comes to the logic of the hierarchy: In its hierarchy, the WBS consists of tasks (the biggest one is the project itself), and then subtasks, and then subtasks to the previous subtasks (usually it is 3 levels deep), while for the RiBS, the hierarchy consists of the project and the related components, whether internal and external. I think an example will make it much clearer (I have listed an example for each one of the deepest elements in the hierarchy):
-- Project Management
--- Methodologies (Wrong methodology is used)
--- Project Manager (The project manager has no experience: no leadership, cannot motivate the team, etc...)
--- Estimates (The estimates are wrong)
--- Plan (Weak project plan is being used)
--- Logistics (There is no place for the team to work on the project)
--- Financial (The organization can no longer fund the project)
--- Supply (the vendor can no longer supply the project with material)
--- Contracts (for example, the vendor may break the contract)
--- Project Team (The project team has weak/irrelevant experience)
--- Technology (The technology used is outdated)
--- Quality (The quality produced is below the project requirements)
Now the above is just an example of a Risk Breakdown Structure, but you can use as a skeleton and expand on it.