Control Panels

[BillB 0]

I have a question concerning concerning control panel disconnect requirements per NFPA 79. It would appear that the a disconnect for all supply voltage/voltages that enter said control panel is/are required to be located physically on the control panel itself. I have an application where I am building a system with two PLC's (located in 2 different physical areas) an HMI (located remotely from the PLC's) and 3 remote I/O stations. A couple of the stations will need to control different supply voltages with separate power feeds for motor control. Obviously, I will be using motor starters for each separate voltage that I will be controlling via PLC, remote I/O or HMI. Nonetheless, it appears from my take on NFPA 79 that I'm required to have a disconnect for the control panels that will separate all ungrounded conductors that pass through the control panel. This would entail a rather ungainly disconnect assy capable of handling a large current and numerous large conductors. I believe I'm missiing something about the requirements of NFPA 79, can anyone help?

[Shiner 2]

I have not had to directly deal with the code in some time but this is what i remember. For each panel, the power that is used for motors, control transformers ect needs to have one main disconnect, rated at the current of the combined loads as specified in the code. When bringing in control wiring that has a source derived elsewhere, as long as that source is protected properly with fusing/breakers you are good. There should be an article on labeling a panel that has 'one or more voltage sources'. If you had to break every line that came in, it would be quite unrealistic. If a panel has only terminals, and the controlling equipment such as motor starters and relays is located elsewhere, it is considered a junction box and those rules do not apply. It is still a good idea to label where they come from, I do not see that in the field enough.