Siemens MICROMASTER 420 Operating Instructions Manual page 28

2 Installation
2.4.1 General
WARNING
The inverter must always be grounded. If the inverter is not grounded correctly,
extremely dangerous conditions may arise within the inverter, which could prove
potentially fatal.
Operation with ungrounded (IT) supplies
It is not permissible to connect MICROMASTER 4 drive converters equipped with
integrated filter to non-grounded line supplies.
If connected to non-grounded line supplies, the 'Y' capacitor must be disabled in
the device. The procedure is described in Attachment B.2.
The MICROMASTER operates on non-grounded line supplies and remains
operational if an input or output phase is connected to ground. In this particular
case, an output reactor must be installed.
Operation with Residual Current Device
If an RCD (also referred to as ELCB or RCCB) is fitted, the MICROMASTER
inverters will operate without nuisance tripping, provided that:
A type B RCD is used.
The trip limit of the RCD is 300mA.
The neutral of the supply is grounded.
Only one inverter is supplied from each RCD.
The output cables are less than 50m (screened) or 100m (unscreened).
Operation with long cables
All inverters will operate at full specification with cable lengths up to 50 m screened
or 100 m unscreened.
When using output reactors as shown in Catalog DA 51.2, the following cable
lengths are possible for all of the types of construction/sizes:
Shielded:
Non-shielded:
28
200 m
300 m
MICROMASTER 420
Issue 07/04
Operating Instructions
6SE6400-5AA00-0BP0