I know very little about National or local building codes, but isn't sending power over Cat5 simular to what is done with thermistats (ie: 24VAC over simular gauge wire)? -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Jeff Barlow Sent: Friday, July 30, 1999 2:15 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: RS485 with a little PIC'up For the final word on this subject look at the National Electrical Code, articles 725 and 800. Your local library should have a current copy. Then check with your local building department for any local amendments. This stuff is a matter of law. In some states (i.e. CA) you are required by law to disclose to a home buyer any known improvements that were not done "to code".