230.67 Service Equipment Surge Protection - https://www.mikeholt.com/code. This new section requiring the installation of a surge-protective device (SPD) for all dwelling unit services has been a long time coming. Up until now, dwelling unit surge protection has been optional and usually an “extra” for the electrician. Section, 230.67, now requires surge protection for all dwelling unit services to protect sensitive life safety devices like smoke and CO detectors from surge damage.