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I have a HMI Located in a class 1 div 2 enclosure. The enclosure is heated with a class 1 div 2 heater as the building heat is turned off from time to time.
Since everything is rated class 1 div 2 I didn't think much of it. When the panel was installed I noticed the connection to the heater was a "sealed" connection which is required for class 1 div 2.
However the wiring within the panel to the HMI is not using Class 1 Div 2 method. Thus when the panel door is opened, the panel is no longer rated class 1 div 2.
The HMI is powered by 24VDC (7 watts) and is class 1 div 2 rated. Could I simply use an intrinsically safe barrier or isolator for the 24 VDC power feeding the HMI? If not then I think the only options are for the operator to have a gas monitor when operating the HMI or we move the HMI panel to a non-classified area.
Any advice would be appreciated.
Thanks
Since everything is rated class 1 div 2 I didn't think much of it. When the panel was installed I noticed the connection to the heater was a "sealed" connection which is required for class 1 div 2.
However the wiring within the panel to the HMI is not using Class 1 Div 2 method. Thus when the panel door is opened, the panel is no longer rated class 1 div 2.
The HMI is powered by 24VDC (7 watts) and is class 1 div 2 rated. Could I simply use an intrinsically safe barrier or isolator for the 24 VDC power feeding the HMI? If not then I think the only options are for the operator to have a gas monitor when operating the HMI or we move the HMI panel to a non-classified area.
Any advice would be appreciated.
Thanks