M40E Chassis Grounding Specifications - Juniper M40E Hardware Manual

M40e Multiservice Edge Router Hardware Guide
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M40e Chassis Grounding Specifications

276
Input current from a DC source other than 48 V (based on maximum configuration;
applies to DC power supply only):
(54 VDC input) x (input current X) = (48 VDC input) x (input current Y)
54 x X = 48 x 50.8 A
X = 48 x 50.8 A/54 = 45.2 A
System thermal output for maximally configured AC-powered router:
Watts DC/85% AC PEM efficiency/0.293 = BTU/hr
2323/0.85/0.293 = 9327 BTU/hr
System thermal output for maximally configured DC-powered router:
105% of Watts DC/0.293 = BTU/hr
1.05 x 2323/0.293 = 8325 BTU/hr
NOTE: As indicated in the preceding list of calculations, even when maximally
configured the router requires no more than 54 A of power.
If you plan to operate a maximally configured DC-powered router, we
recommend that you provision at least 54 A @ 48 VDC and use a facility
circuit breaker rated for 70 A minimum. Doing so enables you to operate the
router in any configuration without upgrading the power infrastructure, and
allows the router to function at full capacity using one power supply.
If you plan to operate a DC-powered router at less than the maximum
configuration and do not provision a 70 A circuit breaker, we recommend that
you provision a circuit breaker rated for at least 125% of the continuous current
that the system draws at 48 V.
M40e Power System Description on page 42
Replacing an M40e AC Power Supply on page 211
Replacing an M40e DC Power Supply on page 215
M40e System Architecture Overview on page 59
To meet safety and electromagnetic interference (EMI) requirements and to ensure
proper operation, the router must be adequately grounded before power is connected.
A pair of threaded inserts (PEM nuts) are provided on the right rear of the chassis for
connecting the router to earth ground.
Copyright © 2010, Juniper Networks, Inc.