I installed such a shield in the AKA switchboard to protect the garage exits and field service exit. We also purchased and installed a 20A, 220V AFCI/GFCI combination switch for the pool pump we installed. Used with a combination of short circuit and GFI circuit breakers to provide maximum pump protection. As protection against interruption, we have installed a residual current circuit breaker in accordance with the current building regulations. The QO style breaker fits snugly into the old Square D panel.