A great way to run cable from shelf to shelf is to build the rack out of pvc pipes. No nails or screws needed. Just cut the pipes to length and they glue to the connectors. They make three way connectors for horizontal - vertical framming. since the pipe is hollow you can drill a small hole at one end and feed the cable under each shelf and then run it back into the pipe and bring it back out for the next shelf up and just continue this until you reach the top shelf. Fire hazzard is also almost non existent as well. It is very light weight. Do a key word search for pvc construction...it is very easy!! Not only do you have bottom heat, but you also have warmer framing as well since the cable runs vertically inside the pipe between each individual shelf.



