M10i DC Power Electrical Safety Guidelines
The following electrical safety
guidelines apply to a DC-powered router:
- A DC-powered router is equipped with a DC terminal
block that is rated for the power requirements of a maximally configured router.
To supply sufficient power, terminate the DC input wiring on a facility
DC source capable of supplying at least 31 A @ –48 VDC
per input for each power supply.
- Incorporate an easily accessible disconnect device into
the facility wiring. We recommend that the 48 VDC facility DC
source should be equipped with a circuit breaker rated at 40 A (–48 VDC) minimum,
or as required by local code. In the United States and Canada, the
48 VDC facility should be equipped with a circuit breaker rated a
minimum of 125% of the power provisioned for the input in accordance
with the National Electrical Code in the US and the Canadian Electrical
Code in Canada.
- Run two wires from the circuit breaker box to a source
of 48 VDC. Use appropriate gauge wire to handle up to 50 A.
- Be sure to connect the ground wire or conduit to a solid
office (earth) ground. A closed loop ring is recommended for terminating
the ground conductor at the ground stud.
- A DC-powered router that is equipped with a DC
terminal block is intended only for installation in a restricted access
location. In the United States, a restricted access area is one in
accordance with Articles 110-16, 110-17, and 110-18 of the National
Electrical Code ANSI/NFPA 70.
 | Note:
Primary overcurrent protection is provided by the building
circuit breaker. This breaker should protect against excess currents,
short circuits, and earth faults in accordance with NEC ANSI/NFPA70. |
- Ensure that the polarity of the DC input wiring is correct.
Under certain conditions, connections with reversed polarity might
trip the primary circuit breaker or damage the equipment.
- For personal safety, connect the green and yellow wire
to safety (earth) ground at both the router and the supply
side of the DC wiring.
- The marked input voltage of –48 VDC for a DC-powered router is
the nominal voltage associated with the battery circuit, and any higher
voltages are only to be associated with float voltages for the charging
function.
- Because the router is a positive ground system,
you must connect the positive lead to the terminal labeled RETURN, the negative lead to the terminal labeled –48V,
and the earth ground to the chassis grounding points.
Published: 2010-10-28