In order to save valuable panel space, the Telecom Industry is constantly looking for ways to reduce the size of it's equipment, while maintaining the international power requirement of 80 VDC. For many years, the industry has been using the Carling A, B & C-Series UL489-A approved breakers to meet these needs.

Recently, Carling was approached by the telecom market leaders, and asked to achieve 80 VDC ratings and UL489-A approvals on the M-Series circuit breaker which would provide them with further panel "down-sizing" opportunities.

Here lies the challenge: As you increase a circuit breaker's voltage rating, the resulting arc between contacts during a short circuit event increases as well. The arc, especially one fed by DC, is a very destructive force. Unlike an AC sine wave, DC does not have a zero current characteristic. Also, UL 489-A requires that a breaker subjected to a short circuit, must open the circuit and subsequently, be "resetable" and operational.

By applying an extensive R&D focus on arc quenching techniques and ultimately redesigning the breaker's arc chamber, Carling's Engineering team was able to increase the M-Series' voltage rating from 65 VDC to 80 VDC and meet UL 489-A.

The M-Series is now available with 80 VDC, UL 489-A construction, as shown on the enclosed table.

Telecommunications equipment, or any 80 VDC application.