Technical Reference
Manual-XPM3m Revision Date: August 2014
ELECTRICAL GROUNDING OF OVEN
GENERAL:
1) All ground wires have green or green/yellow insulation. Ground wires without green or green/yellow
insulation are identified using green or green/yellow tape.
2) The main electrical panel has a single ground terminal. All grounds must be connected to the ground
terminal.
3) Bare copper grounding wire inserted into an aluminum grounding block should be coated with an
oxidation inhibitor. Copper to aluminum has a natural galvanic reaction, which will degrade the
electrical connection in a short time. Inhibitor is not required when ferrules are used.
4) Use long nose pliers when inserting a ground wire into a double layered ground block. Insert the wire
completely into the block for a proper ground bond.
5) Ground blocks should be mounted on a clean and paint free surface. Use a star washer under the
mounting screws.
Test procedure for system ground continuity
1) Check continuity between the main ground terminal of the oven and the ground terminal on the
mains connecting plug or distribution board using an Ohmmeter.
2) Check continuity from the mains ground terminal of the oven to each individual component using an
Ohmmeter.
3) The resistance values should not exceed one Ohm.
Test procedure for insulation leakage (MEGGER [or Resistance] TEST)
1) Disconnect the system from the mains supply
2) Connect the three phases together at the mains supply connection point on the oven.
3) Disconnect the Circuit Breakers supplying the control circuit transformer and the circuit breaker
supplying the inverter.
4) Disconnect the computer and all peripheral equipment from the oven.
5) Connect an insulation test meter between one of the three phases and the ground connection point.
6) Turn on the Main Disconnect and test the system insulation for leakage at twice the single-phase
voltage. For example, for 240 VAC phase to neutral, check insulation at 500 Volts.
7) The resistance should be at least 1 MegOhm.
