AT&T 76450 User Manual

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Common Systems Connection Standards AT&T Services, Inc
Date: June 2013

ATT-TP-76450, Issue 15

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2.6.2

Is the equipment planned for placement in a switching environment?
A “YES” answer here will not require the use of fuses but circuit breakers are
required for circuit power protection.

2.6.3

Is the equipment planned for placement in the transport environment?

A “Yes” answer here will require the use of fuses or a fuse panel to interface to
the power plant.

2.6.4

Fuses

Fuses are the preferred method of power protection. The equipment fuse shall be replaceable
by the maintenance technician on site. If the shelf / system is protected by fuses rated at 120
amps or less, a bay mounted fuse panel is not required.

A “YES” answer here confirms that the equipment is protected by fuses rated at 120
amps or less and are replaceable by the maintenance technician on site.

Any equipment that requires more than a 70 amp fuse (56 amp load of List 2X) may
necessitate modifications to the BDFB to accommodate a fuse larger than 70 amps. Individual
equipment will not be directly fed from Power Board Distribution without the use of an SPDU or
BDFB.

2.6.5

Approved Fuse Types

All fuses provided on the equipment and approved PDUs shall be equipped with at least one of
these forms of overprotection devices, (1) GMT Fuses, (2) Telpower® Fuses, (3) Telecom TLS
Fuses. The size of the DC requirement will serve as the primary qualifier. Only approved fuse
types shall be utilized. The approved fuse types are GMT, TPA, TPN, TPS and TLS.

•

GMT Fuses – Generally sized to accommodate 0.18 – 20 amp requirements. List 2X

demand should not exceed 80% rated fuse size.

•

Telpower® Fuses – as listed above - Exclusively produced by Cooper-Bussmann,

these fuses are available in sizes from 3 amps to 600 amps, packaged in Blue to
signify DC only. All Telpower® fuses should be sized at 125% of List 2X load (List
2X load not greater than 80% of their fuse faceplate rating).

•

Telecom TLS Series Power Fuses – Exclusively manufactured by Littelfuse shall be

used in the 3-125A sizes with the Canadian Shunt TFD101-011-01 fuse
disconnect/fuse holder. Littelfuse TLS fuses should be sized at 125% of List 2X load
(List 2X load not greater than 80% of their fuse faceplate rating).

A “YES” answer here confirms that the equipment is protected by an approved fuse type
rated at 120 amps or less.