Page 6 - SACE Tmax XT - Technical Catalogue

1/2 SACE TMAX XT LOW VOLTAGE MOLDED CASE CIRCUIT-BREAKERS

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Installation environment

Temperature

The Tmax XT circuit-breakers can be used in environmental conditions where the ambient air temperature
varies between -25°C and +70°C, and can be stored at temperatures between -40 °C and +70 °C.
Circuit-breakers fitted with thermomagnetic trip units have their thermal element set for a reference
temperature. For temperatures other than the reference, a trip threshold variation must be taken into ac-
count. Electronic trip units do not undergo any variations in performance as the temperature varies, but,
in the case of temperatures exceeding +40°C, the maximum setting for protection L (protection against
overloads) must be reduced, as indicated in the derating graph, to take into account the heating pheno-
mena which occur in the copper parts of the circuit-breaker which the phase current passes through. For
temperatures above +70°C the circuit-breaker performances are not guaranteed.

Environmental conditions

The Tmax XT circuit-breakers are designed to operate in environments with a pollution degree of 3 ac-
cording to the IEC 60947-2 Standard classification.
Altitude
Up to an altitude of 2000m, the Tmax XT circuit-breakers do not undergo any alteration in their rated per-
formances. As the altitude increases, the atmospheric properties are altered in terms of composition,
dielectric resistance, cooling capacity and pressure. Therefore, some performance aspects of the circuit-
breaker (e.g. the maximum rated operating voltage and the rated uninterrupted current) undergo derating.

Altitude 2000m 3000m 4000m 5000m
Rated service voltage, Ue [V] 690 621 540 470
Rated uninterrupted current % 100 98 93 90

Shocks and vibrations
The Tmax XT circuit-breakers are unaffected by vibrations generated mechanically and due to electro-
magnetic effects, in compliance with the IEC 60068-2-6 Standards and the regulations of the major ship-
ping registers including:
• RINA
• Det Norske Veritas
• Bureau Veritas
• Lloyd’s Register of Shipping
• Germanischer Lloyd
• ABS
• Russian Maritime Register of Shipping
• Nippon Kaiji Kyokai.
The Tmax XT circuit-breakers are also tested according to the IEC 60068-2-27 Standard to resist shocks
up to 15g for 11 ms.

Electromagnetic compatibility
Protection is guaranteed in the presence of interference caused by electronic apparatus, atmospheric
disturbances or electrical discharges by using the electronic trip units and the electronic residual current
releases. No interference with other electronic apparatus near the place of installation is generated ei-
ther. This is in compliance with the IEC 60947-2 Annex B + Annex F Standards and European Directive
No. 2014/30/EC regarding EMC - electromagnetic compatibility.