Hypertherm HD4070 Rev.1 - Manual (Page 261)

HyPerformance HD4070 Instruction Manual a-1
System grounding requirements
The plasma system must be grounded for safety reasons and to suppress EMI:
• Safety The entire system—power supply, accessory enclosures, and worktable—must be grounded to protect it
and the operator from a ground fault. The protective earth (PE) ground connections must be installed by a
licensed electrician and conform to national or local codes.
• EMI Suppression If allowed by national or local codes, the ground system can also be used to suppress EMI
(electromagnetic interference). Below is a guide to configure the plasma system for minimal EMI. See
Electromagnetic Compatibility in this manual for additional information.
Suggested ground cable routing
Power supply
Connect the power supply to the PE ground terminal, using a properly sized color-coded conductor. This PE ground
is connected to the service ground through the line disconnect switch. See the Installation section for further
information on the power cord and the line disconnect switch.
Equipment grounding
All accessory modules that receive power from the plasma power supply must also use the power supply’s
ground—either by connection to the PE terminal of the power supply, or by direct connection to the equipment
ground conductor. Each module should have only one connection to ground to avoid ground loops and stray
currents. If any enclosure is grounded to the work table, the work table must be grounded to the power supply.
Effective grounding for EMI reduction is highly dependent upon the installation configuration. Two acceptable
configurations are shown in Figures a-1 and a-2.
The ignition console should be installed near the work table, and grounded directly to it. Other modules should be
installed near the power supply, and grounded directly to it (Figure a-1).
Appendix A
SYSTEM GROUNDING