Sun Microsystems 1800 manual DC Source Site Requirements, Overcurrent Protection Requirements

Note –The system On and Stby switches handle low voltage signals only; the high- power circuits do not pass through these switches.

DC Source Site Requirements

The DC source site requirements are as follows:

■Suitable for use in –48 Vdc ((classified SELV) nominal or –60 Vdc (classified TNV-2) nominal systems.

■The supply source must be electrically isolated by double or reinforced insulation from any hazardous AC or DC source.

■The DC source must be reliably connected to earth (that is, battery room positive bus is connected to the grounding electrode).

■The DC source must be capable of providing up to 925W of continuous power per feed pair. The sum of all three feeds on one side will be less than 1500W for single-feed and 3000W for dual feed.

Overcurrent Protection Requirements

Overcurrent protection devices must be provided as part of each host equipment rack.

Circuit breakers meeting the requirements shown in TABLE 3-1must be fitted between the DC source and the Netra ft 1800.

TABLE 3-1Overcurrent Protection Requirements

Current rating	30A maximum
Voltage	Maximum 60 Vdc rated in –48 Vdc power systems
	Maximum 75 Vdc rated in –60 Vdc power systems
Type	Fast trip
Protection	Double pole breaking (both grounded and ungrounded conductor
	open on fault)
Contact gap	Minimum 3 mm
Nuisance tripping	Circuit breaker must not operate when presented with an inrush
	current of 27 amps and a duration of 2.5 microseconds
Quantity	One per feed, up to 12 per system

44 Netra ft 1800 Installation Guide • February 1999