You'd be wise to have Sparky run completely new grounded wiring all the way from the service panel to the new boxes. Possibly even consider doing so to more existing circuits, especially those that have higher draws. Or go the whole hog and replace the entire service panel with a new (200 A.) one using completely new wiring and circuit breakers, instead of those pesky fuses you're always replacing now. At least around here, most home fires are electrical-related or dirty dryer vents.