We have a press machine, The E-stop isloates the motor to generate pressuree and movement controls of the press. However there are some heating elements in the press machine using 400 Vac. Should the E-stop be used to isloate the heating circuit too just incase something goes wrong? Logically it sounds right to isloate but my colleages disputes with me. The standard says only to isolate all the actuators i.e moevments. Please help me for an answer.

Coming from a background of working with many heat producing machines I would never expect a E.Stop button to isolate or stop the heated elements.

As mentioned above, E.Stop's are for stopping machines in an emergency, not isolating them. If the power was also cut to the element, what benefit would this have? The element will still be hot, and will remain so for a long time. If it was going to burn you before the E.Stop was pressed, it will still burn you even if the power was cut. The element would also slowly cool, causing the start up time for the machine to increase, this in turn introduces other hazards if the machine is not functioning properly.

The safe method was to restrict all access to any heated parts, so that the E.Stop would not be the control to prevent burns. When maintaining or cleaning machines with heated parts the machine was always isolated (as it should be) and the hot parts were given sufficient time to cool down.

For reference I worked in the polythene industry, both extruding and manufacturing polythene envelopes. If you are talking about something that this experience wouldn't relate to your experience may be different.

Your post & profile gives no indication of the location of the device. If it was designed in the EU (CE) then a technical file would exist describing the rationale for, and inclusion of, safety devices.

400 Volts would indicate significant heating on the press so the laws of physics would likely require a significant amount of time to dissipate this energy to a safe level. For the system to restrict access to a thermal danger would require a timer/sensor operated interlock guard.

Regardless an E-Stop in itself is not an appropriate isolation technique - electrical power shoud be locked off at the main distribution board and/or local feeder board isolation switch. The associated procedure should describe any time delays or checks to follow before persons enter any zone of potential danger.