rollcage fabrication ?

[JonT]

You don't get it certified as such, look at the regulations for what ever your doing, that will probably have the requirements for your cage. As long as you meet those regulations your cage will be acceptable. This will be checked at scruitineering before and event. For lots of events a cage isn't required, sometimes its only a roll bar.

It's worth remembering that a roll cage provides two useful roles, firstly for safety and secondly for improving the ridigity of the car. So you might want to use a full cage even though it's not required to stop chassis flex etc.