Overvoltage Category - SMA SUNNY BOY 1.5 Operating Manual

6 Electrical Connection
☐ The cable must be dimensioned in accordance with the local and national directives for the
dimensioning of cables. The requirements for the minimum wire size derive from these
directives. Examples of factors influencing cable dimensioning are: nominal AC current, type
of cable, routing method, cable bundling, ambient temperature and maximum desired line
losses (for calculation of line losses, see the design software "Sunny Design" from software
version 2.0 at www.SMA-Solar.com).
Load-break switch and cable protection:
Damage to the inverter due to the use of screw-type fuses as load-break switches
Screw-type fuses (e.g. DIAZED fuse or NEOZED fuse) are not load-break switches.
• Do not use screw-type fuses as load-break switches.
• Use a load-break switch or circuit breaker as a load disconnection unit (for information and
design examples, see the Technical Information "Circuit Breaker" at www.SMA-Solar.com).
☐ In PV systems with multiple inverters, protect each inverter with a separate circuit breaker.
Make sure to observe the maximum permissible fuse protection (see Section 15 "Technical
Data", page 85). This will prevent residual voltage being present at the corresponding cable
after disconnection.
☐ Loads installed between the inverter and the circuit breaker must be fused separately.
Residual-current monitoring unit:
☐ If an external residual-current device is required, install a residual-current device which trips at
a residual current of 100 mA or higher (for details on selecting a residual-current device, see
the Technical Information "Criteria for Selecting a Residual-Current Device" at www.SMA-
Solar.com).

Overvoltage category:

The inverter can be used in grids of overvoltage category III or lower in accordance with
IEC 60664-1. That means that the inverter can be permanently connected to the grid-connection
point of a building. In case of installations with long outdoor cabling routes, additional measures to
reduce overvoltage category IV to overvoltage category III are required (see the Technical
Information "Overvoltage Protection" at www.SMA-Solar.com).
Grounding conductor monitoring:
The inverter is equipped with a grounding conductor monitoring device. This grounding conductor
monitoring device detects when there is no grounding conductor connected and disconnects the
inverter from the utility grid if this is the case. Depending on the installation site and grid
configuration, it may be advisable to deactivate the grounding conductor monitoring. This is
necessary, for example, in an IT system if there is no neutral conductor present and you intend to
install the inverter between two line conductors. If you are uncertain about this, contact your grid
operator or SMA Solar Technology AG.
• Grounding conductor monitoring must be deactivated after initial start-up depending on the
grid configuration (see Section 9.11, page 56).
26 SB15-25-1VL-40-BE-en-11
SMA Solar Technology AG
Operating Manual