Casting Mold Heater Question

[fraymond]

I have a project that uses 3ph 220V/50A service that controls a temperature unit to a casting mold. The casting mold is on wheels and has cables that plug the TC's and power cables into the temperature controller unit. A single ckt brkr on the temperature control unit is used to turn the system on and off i.e. off to plug the cables in and on to control the temperature. This casting fixtures will be rolled into a caged area for safety purposes.
I am proposing that I use a combination 60A contactor/disconnect that is controlled by a low voltage start/stop station and an interlock on the cage gate to prevent entry while the contactor is turned on. Later on I will install a timer to also turn the contactor off and a LED monitor that will show the operator the all 3 phases are removed after the contactor is removed and not to be used as a LOTO indicator. These items will show the operator it is safe to install/remove the cables to the casting mold.
I am asking for an opinion. Please be brutally honest. Thanks in advance...

 

[Jraef]

I would do this with a Safety Relay system, after having someone perform a Risk Analysis. In this country we don't yet require this as they do virtually everywhere else in the developed world, but it's coming soon to a theater near you and when it does, you will likely have to rip and replace. Better to just do it the right way the first time.