Chassis Grounding Issues:
The Metal chassis should be effectively bonded to a main grounding point in the rack cabinet where
necessary to assure electrical continuity and shall have the capacity to conduct safely any fault
current likely to be imposed on it. See Ground Lug Manufacturers
In a chassis with ac service connected to it, the grounding terminal of its receptacle shall be internally bonded to the chassis frame. If solder is used, the connection of the equipment grounding conductor shall not depend on solder alone. An equipment chassis that only use a bolt and nut to form a grounding point should be avoided as that would not be bonded, unless it was welded.
AC EMI Filter
Input/output ac power connections to the chassis shall comply with NEC requirements. Most if not all commercial connectors would comply with NEC requirements, so this should not be an issue.
The exposed, non-current carrying, metal parts of panel mount connectors operating at 50 volts or
greater shall be bonded to the chassis.
Plugs and sockets for connecting any AC power source shall be NRTL [Nationally Recognized Testing Laboratory] approved for the application. This statement would include Underwriters Laboratory [UL] in the U.S.
AC power sockets and plugs shall not be used for purposes other than the connection of AC power. This statement would include commercial sockets only, not all military sockets that could be used as AC sockets may not be specifically be called out for AC operation.
Connectors operating at 50 V or greater shall be rated or recommended for their intended use.
Any connector used to provide power at 50 V or greater shall not allow personnel to make inadvertent
contact with the power source.
If plug pins of cord-connected equipment receive a charge from an internal capacitor, the pins shall
not be capable of rendering an electric shock or electric burn in the normal or the single fault condition
5 seconds after disconnection of the supply.
Plug-in type connectors intended to be connected and disconnected by hand shall be designed so that
the grounding conductor connection makes first and breaks last with respect to the other connections.
All terminals and live parts with a potential of 50 volts or greater shall be guarded to protect from
accidental contact by personnel or bringing conductive objects in contact with them. Guards or barriers may be provided with test probe holes where maintenance testing is required. Plastic strips attached to the chassis frame are commonly used as guards.
All Equipment Enclosures containing exposed energized circuits over 600 volts nominal should be marked
Danger High Voltage Keep Out with a label that is permanent. Assemblies operating at potentials in excess of 500 volts
should be completely enclosed from the remainder of the assembly and equipped with non-bypassable
interlocks. Also see Rack Grounding guidelines and recommendations.
Section Index; How To Specify a Equipment Chassis
