Operation Manual

Chapter 3 Installing the Electrical Supply 13
Overcurrent Protection Requirements
■ Overcurrent protection devices must be provided as part of each host equipment
rack.
■ Two 15A single-pole, fast trip, DC-rated circuit breakers (one per ungrounded
supply conductor) must be located in the negative supply conductor between the
DC power source and the Netra t 1400 system.
■ Circuit breakers must not trip when presented with inrush current of 20A lasting
250ms.
Note – Overcurrent devices must meet applicable national and local electrical safety
codes and be approved for the intended application.
Connection Materials
Grounding
■ One Thomas & Betts two-hole lug (part number: 54204-UB) suitable for 8AWG
conductor or UL/CSA approved equivalent having 5/8-inch pitch. Torque value:
3.5Nm maximum. Two M5 studs and cupwasher nuts are supplied on the rear of
the chassis for connection.
■ A Thomas & Betts crimping tool (part number: TBM 5-S), or approved equivalent
is required to secure the lug on to the cable.
■ An earthing bus bar that is near the equipment and easily accessible.
Caution – External filtering and/or surge suppression devices may be required on
the power feeds where branch circuit electromagnetic characteristics are unknown.
DC Supply and Ground Conductor
The requirements are:
■ Suitable conductor material: tinned copper only
■ Conductors: 12 AWG maximum (between the Netra t 1400 and circuit breaker).
There are three conductors:
■ -48VDC/-60VDC Supply (pin 1)
■ Ground connection to power supply (pin 2)
■ -48VDC/-60VDC Return (pin 3)
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LW3User.book Page 13 Wednesday, November 10, 1999 9:00 AM