As a home owner, I have an ongoing issue which is that everytime any motor kicks on (refrigerator, AC condenser, sabre saw, etc.) the lights dim for a second or two. The main service is at the detached garage and is properly bonded and attached to a grounding rod. This panel feeds the sub panel which is located in the house about 50' away. This sub panel is also bonded and attached to both a grounding rod and cold water pipe. I questioned the electrician about this and he said that it was required by code since they are 2 different buildings. BTW, the work was inspected. Is this accurate? Is this why I'm experiencing the temporary voltage dips, or is there another possibility? Much thanks.