What is an acceptable method of running a ring main through floor joists? Can I bore just one hole through each joist and run both cables for the ring through that? Or one smaller hole for each cable. The cable will run the length of the hallway to the kitchen so there's probably about 10 joists to bore through. Also I want to install Earth bonding from kitchen to CU. Can I run the 10 mm green/yellow through the same set of joist holes as one of the 2.5 T+E? All help appreciated. Steve.