Disconnecting the chassis from power

Follow the instructions in this section to disconnect the Flex System Carrier-Grade chassis from all power sources.

Before you disconnect the Flex System Carrier-Grade chassis from power, be sure to follow these instructions to correctly shut down the compute nodes.

Statement 19


Graphic illustrating Safety Statement 19
CAUTION:
The power-control button on the device does not turn off the electrical current supplied to the device. The device also might have more than one connection to dc power. To remove all electrical current from the device, ensure that all connections to dc power are disconnected at the dc power input terminals.

Graphic illustrating Safety Statement 19

Graphic illustrating Safety Statement 19

Statement 31



DANGER
Electrical current from power, telephone, and communication cables is hazardous.

To avoid a shock hazard:

  • Do not connect or disconnect any cables or perform installation, maintenance, or reconfiguration of this product during an electrical storm.
  • Connect all power cords to a properly wired and grounded power source.
  • Connect to properly wired power sources any equipment that will be attached to this product.
  • When possible, use one hand only to connect or disconnect signal cables.
  • Never turn on any equipment when there is evidence of fire, water, or structural damage.
  • Disconnect the attached ac power cords, dc power sources, network connections, telecommunications systems, and serial cables before you open the device covers, unless you are instructed otherwise in the installation and configuration procedures.
  • Connect and disconnect cables as described in the following table when you install, move, or open covers on this product or attached devices.
To Connect: To Disconnect:
  1. Turn OFF all power sources and equipment that is to be attached to this product.
  2. Attach signal cables to the product.
  3. Attach power cords to the product.
    • For ac systems, use appliance inlets.
    • For dc systems, 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. Attach signal cables to other devices.
  5. Connect power cords to their sources.
  6. Turn ON all the power sources.
  1. Turn OFF all power sources and equipment that is to be attached to this product.
    • For ac systems, remove all power cords from the chassis power receptacles or interrupt power at the ac power distribution unit.
    • For dc systems, disconnect dc power sources at the breaker panel or by turning off the power source. Then, remove the dc cables.
  2. Remove the signal cables from the connectors.
  3. Remove all cables from the devices.

Statement 33


Graphic illustrating Safety Statement 33
CAUTION:
This device does not provide a power control button. Removing power supply modules or turning off the server blades does 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.

Graphic illustrating Safety Statement 33
Attention: The following circuit breaker and ground cable ratings apply to chassis equipped with -48 V dc power supplies:
Breaker Listed 70 A See Note 1
Ground cable 4 AWG with Listed lug which can accept M6 ground screws See Note 2
Torque rating for ground screws 4.0 - 4.8 Newton-meters (35.4 - 42.5 inch-pounds) -
  1. The maximum steady state current of the -48 V dc power supply is less then 70 A. However during specific events, such as over subscription, it is possible for the power supply to briefly draw a current greater than 70 A. Therefore it is recommended that the power supply be protected by a Listed circuit breaker that will support up to 90 A for a minimum of 20 ms. The suggested Telect High Current Panel Dual 350A Power Distribution Panel (part number 350CB06) using the Telect 70 A circuit breakers (Part number 090-0052-0070) conforms to this specification.
  2. If not connecting to a SELV source which provides Reinforced insulation you must use a Ground Cable.

To disconnect the chassis from power, complete the following steps:

  1. Shut down each compute node. See the documentation that comes with the compute nodes for information about shutting down the operating systems on the compute nodes.
  2. Disconnect all power cords on the rear of the chassis from the power source.
    Note: After you disconnect the chassis from power, wait at least 5 seconds before you connect the chassis to power again.
Parent topic: Installing the Flex System Carrier-Grade chassis