SMA STP 50-40 - 6.5 DC Connection

6 Electrical Connection
SMA Solar Technology AG
Operating manualSTP50-4x-BE-en-2348
6.5 DC Connection
6.5.1 Requirements for the DC Connection
Requirements for the PV modules per input:
☐ All PV modules should be of the same type.
☐ All PV modules should be aligned and tilted identically.
☐ On the coldest day based on statistical records, the open-circuit voltage of the PV array must
never exceed the maximum input voltage of the inverter.
☐ The same number of series-connected PV modules must be connected to each string.
☐ The maximum input current per string must be maintained and must not exceed the through-
fault current of the DC connectors (see Section13, page120).
☐ If only one input per MPPT tracker is assigned and AFCI is used at the same time, the
maximum input current of the input must not exceed 16A.
☐ The thresholds for the input voltage and the input current of the inverter must be adhered to
(see Section13, page120).
☐ The positive connection cables of the PV modules must be equipped with positive DC
connectors (see Section6.5.2, page48).
☐ The negative connection cables of the PV modules must be equipped with the negative DC
connectors (see Section6.5.2, page48).
Use of Y adapters for parallel connection of strings
The Y adapters must not be used to interrupt the DC circuit.
• Do not use the Y adapters in the immediate vicinity of the inverter. The adapters must not
be visible or freely accessible.
• In order to interrupt the DC circuit, always disconnect the inverter as described in this
document (see Section9, page91).
6.5.2 Assembling the DC Connectors
DANGER
Danger to life due to electric shock when live components or DC cables are
touched
When exposed to light, the PV modules generate high DC voltage which is present in the DC
cables. Touching live DC cables results in death or lethal injuries due to electric shock.
• Do not touch non-insulated parts or cables.
• Disconnect the product from voltage sources and ensure it cannot be reconnected before
working on the device.
• Do not disconnect the DC connectors under load.
• Wear suitable personal protective equipment for all work on the product.