Miniature Circuit Breakers protect up to 480 Y/277 Vac systems.

Press Release Summary:

Used for branch circuit protection, GMB Series includes UL489, AC, miniature molded circuit breakers that come in 1-, 2-, and 3-pole arrangements ranging from 0.5–63 A. Short circuit interrupt capacity is 10 kA. Used for supplementary circuit protection, GSB Series includes UL1077, AC, supplementary circuit protectors that come in 1-, 2-, 3-, and 4-pole variations that range from 1–63 A and have short circuit interrupt capacity of 5 kA. Both series have 17.5 mm wide housings (per pole).

Original Press Release:

Mini Circuit Breakers UL489 and UL1077 Type

Buffalo Grove, IL – CARLO GAVAZZI has launched a new range of Miniature Circuit Breakers for up to 480Y/277VAC systems: GMB Series UL489 MCBs for Branch Circuit Protection and GSB Series UL1077 MCBs for Supplementary Circuit Protection.

The GMB Series are UL489, AC miniature molded circuit breakers, which provide reliable protection for a wide range of applications including branch circuit protection of HACR equipment, power supplies, transformers, motors, receptacles and other equipment.  1, 2 and 3 pole arrangements are available, ranging from 0.5A to 63A, with short circuit interrupt capacity of 10kA. The GMB Series circuit breakers are UL listed and conform to IEC standard EN-60947-2.

The GSB Series are UL1077 AC supplementary circuit protectors, which offer overcurrent protection for specific applications where branch circuit protection is already provided by another device or is not required. They are available in 1, 2, 3 and 4-pole variations, ranging from 1 to 63Amps and have a short circuit interrupt capacity of 5kA. The GSB Series are UL recognized components.

The new GMB Series UL489 branch circuit protectors and GSB Series UL1077 supplementary protectors are housed in compact 17.5mm wide housings (per pole), with robust DIN-rail mounting and red/green diagnostic trip indicators. C tripping curve is standard, with B & D tripping curves available upon request.

GMB Series UL489 Branch Circuit Protectors

• 1, 2 and 3 Pole from 0.5 to 63Amp

• 480Y / 277VAC maximum voltage rating

• 10kA short circuit rating

• cULus listed

GSB Series UL1077 Supplementary Circuit Protectors

• 1, 2, 3 and 4 Pole from 1 to 63Amp

• 480Y / 277VAC maximum voltage rating

• 5kA short circuit rating

• UL recognized 

The GMB and GSB Series are available from Carlo Gavazzi’s North American network of sales offices and distributors, or at

Questions regarding this press release should be directed to:

CARLO GAVAZZI Inc., 750 Hastings Lane, Buffalo Grove, IL  60089

Phone: 847.465.6100     Fax: 800.222.2659     Email:,

CARLO GAVAZZI (Canada) Inc., 2660 Meadowvale Blvd., Mississauga, ON  L5N 6M6

Phone: 888.575.2275     Fax: 905.542.2248     Email:

CARLO GAVAZZI Mexico S.A. de C.V., Calle La Montaña no. 18, Fracc. Los Pastores, Naucalpan de Juárez, EDOMEX CP 53340     Phone/Fax:  55.5373.7042     Email:

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