Electrical Connection
SMA America, LLC
50
SB50US-80US-eng-IUS112633
Installation Guide
6.5.3 DC Wiring without SMA DC Disconnect
Use the following procedure to connect the DC cables to the Sunny Boy without SMA DC Disconnect:
1. Open the AC breaker and secure against turning on again.
2. Open the DC disconnect switch and secure against turning on again.
3. Install a
3
⁄
4
in. cable gland in the opening for the DC cables. Observe section 6.2 ”Opening the
Sunny Boy” (page 38) and the following figure. Secure the cable gland to the inner side of the
Sunny Boy with the matching locknut.
4. Install a
3
⁄
4
in. cable conduit between the enclosure of the DC disconnect switch and the
breakout opening for DC cables on the Sunny Boy.
5. For steps 6 to 8, note the following figure.
6. Pull the DC cables from the DC disconnect switch through the cable conduit and inside the
Sunny Boy.
7. Connect the positive DC cable to the terminal in the Sunny Boy labeled DC+.
8. Connect the negative DC cable to the terminal in the Sunny Boy labeled DC − .
9. Connect the positive and negative DC cables to the terminals provided in the enclosure of the
DC disconnect switch.
Item
Description
A
Positive DC cable connected to DC+
B
Negative DC cable connected to DC–
C
DC enclosure opening
The Sunny Boy has provisions for up to 3 PV strings. The positive and negative terminal
blocks each have 3 connection points. This means that 3 pairs of DC input cables can be
connected in parallel.
Fully open the terminal before feeding through the cables.
