Lenovo ThinkSystem SR850 V2 Maintenance Manual page 183

The power-control button on the device and the power switch on the power supply do not turn off the
electrical current supplied to the device. The device also might have more than one power cord. To
remove all electrical current from the device, ensure that all power cords are disconnected from the
power source.
S029
DANGER
For -48V dc power supply, electrical current from power cables is hazardous.
To avoid a shock hazard:
• To connect or disconnect -48V dc power cables when you need to remove/replace install
redundancy power supply unit(s).
To Connect:
1. Turn OFF subject dc power source(s) and equipment
(s) that are attached to this product.
2. Install the power supply unit(s) into the system
housing.
3. Attach dc power cable(s) to the product.
• Ensure correct polarity of -48 V dc connections:
RTN is + and -48 V dc is -. Earth ground should
use a two-hole lug for safety.
4. Connect dc power cable(s) to subject power source
(s).
5. Turn ON all the power source(s).
S035
CAUTION:
Never remove the cover on a power supply or any part that has this label attached. Hazardous voltage,
current, and energy levels are present inside any component that has this label attached. There are no
serviceable parts inside these components. If you suspect a problem with one of these parts, contact
a service technician.
Following are the types of power supply units compatible to this server and notices to take during
installation. These power supplies are designed for parallel operation. In the event of a power supply failure,
the redundant power supply continues to power the system. The server supports a maximum of two power
supply units with N+1 redundancy support.
• 750-watt Titanium, input power 230 Vac / 240 VDC
To Disconnect:
1. Disconnect or turn off the subject dc power source(s)
(at the breaker panel) before removing the power
supply unit(s).
2. Remove the subject dc cable(s).
3. Unplug the subject power supply unit(s) from the
system housing.
.
Chapter 4 Hardware replacement procedures
175