Grounding faults in the line voltage supply will make any instrument con-nected to it dangerous. Before con-necting any unit to the power line, you must make sure that the protective ground functions correctly. Only then can a unit be connected to the power line and only by using a three-wire line cord. No other method of grounding is per-mitted. Extension cords must always have a protective ground conductor.

WARNING: If a unit is moved from a cold to a warm environment, con-densation may cause a shock hazard. Ensure, therefore, that the grounding requirements are strictly met.

WARNING: Never interrupt the grounding cord. Any interruption of the protective ground connec-tion inside or outside the instrument or disconnection of the protective ground terminal is likely to make the instrument dangerous.