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Grey Siemens BQ3B020 miniature circuit breaker, three toggle poles, bolt-on lugs

SIEMENS

SIEMENS BQ3B020 Miniature Circuit Breaker 20A 3 Pole 240V AC

SKU CH-5FK1-PHGV5

Three-pole 20 A breaker rated 240 V AC with 10 kA interrupting capacity, bolt-on mounting and lug terminals for Siemens panelboards

  • Protects three-phase circuits with 10 kA interrupting capacity at 240 V AC
  • Handles 20 A continuous load on a standard bolt-on frame
  • Fits Siemens panelboards using lug terminals for 14–10 AWG copper or 12–10 AWG aluminium
  • Operates reliably up to 104 °F ambient temperature
  • Compact 3.7 × 4.6 × 12.8 in footprint saves panel space

SIEMENS BQ3B020 Miniature Circuit Breaker

The SIEMENS BQ3B020 is a 20A three-pole miniature circuit breaker rated for 240V AC with a 10kA interrupting rating. It belongs to the BQ series and uses a bolt-on mounting style designed for Siemens panelboards. The unit features a toggle actuator and lug terminal connections suitable for 14 AWG copper or 12 AWG aluminium minimum wire up to 10 AWG maximum.

Bolt-on installation in Siemens panelboards

Installation requires bolting the breaker directly onto the panelboard bus, which demands correct alignment and torque on the mounting hardware. The lug terminals accept wire sizes from 14 AWG copper or 12 AWG aluminium up to 10 AWG maximum. Common issues include loose lug connections leading to overheating and misaligned bolt-on mounting causing poor bus contact.

Three-phase 240V AC loads up to 20A

This breaker suits commercial or industrial three-phase circuits requiring 20A protection at 240V AC within compatible Siemens panelboards. It is not for DC applications, single-phase loads needing only one or two poles, or systems requiring a higher interrupting capacity than 10kA at 240V AC. Buyers needing different amperage, pole count, or voltage ratings should look at other models.

Highlights

  • Protects three-phase circuits with 10 kA interrupting capacity at 240 V AC
  • Handles 20 A continuous load on a standard bolt-on frame
  • Fits Siemens panelboards using lug terminals for 14–10 AWG copper or 12–10 AWG aluminium
  • Operates reliably up to 104 °F ambient temperature
  • Compact 3.7 × 4.6 × 12.8 in footprint saves panel space

Specifications

BrandSIEMENS

Questions about this item

How can I confirm the breaker is working after I bolt it into my Siemens panelboard?

After mounting the bolt-on BQ3B020 in a compatible Siemens panelboard, switch the toggle to ON and verify that the protected three-phase circuit carries load without the 20 A device tripping.

What comes in the box and what must I supply myself?

The package contains the 3-pole 20 A miniature circuit breaker with integrated lug terminals; you must provide 12 AWG aluminium or 14 AWG copper conductors up to 10 AWG maximum and a suitable Siemens panelboard for bolt-on mounting.

Which BQ series version should I choose for a 240 V AC three-phase panel?

Select the BQ3B020 when you need a 20 A, 3-pole, 240 V AC standard breaker with a 10 kA interrupting rating that fits a 125 A frame and bolts into a Siemens panelboard.

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