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Inspecting Quad Circuit Breakers

Not to be confused with 2 – 240 volt double pole circuit breakers; quad circuit breakers take up less space (2 slots instead of 4) in service panels but still allow for up to 4 – 120 volt circuits, 2 – 120 volt circuits and one 240 volt circuit, or 2 – 240 volt circuits. Modern quad circuit breakers are 2 tandem circuit breakers that are joined internally and externally with a link or handle tie for the 240 volt circuit. Used to add a 240 Volt circuit (s) or up to 4 (multi) branch circuits in a panel that is full.

In the above picture it is a 240 volt 30 amp circuit (10 AWG wire) – red and black connected to outer breakers and joined with a metal handle tie

Center two 20 amp breakers are not joined and are separate circuits

This is an older quad breaker so the outer 240 volt circuit is dependent on the metal handle tie to disengage both legs of the circuit, which may fail. If you see this, recommend a licensed electrician upgrade to a newer quad circuit breaker that is also internally linked like this:


The above quad breaker would allow for 2 separate 15 amp circuits and one 30 amp, 240 volt circuit. As earlier stated, you could also use quad breakers for multi-branch circuits. Remember, if wired for a 240 volt circuit or for a multi-branch circuit, ensure both hot conductors are on opposite poles. The above quad breaker has one 15 amp & one 30 amp on each pole. Using the above breaker as an example:

  • One 14 gauge conductor (black / hot) will go to the 15 amp breaker on the far left, and one on the far right 15 amp breaker. Both neutrals go to the neutral bus. Grounds to the ground bus. These 2 breakers now work as independent 120v, 15 amp circuits.

  • Two 10 gauge conductors (black / red) would be connected to the 30 amp center breakers. Neutral and ground to the proper bus. This now functions like a 240v, 30 amp double pole circuit.

If they are not wired correctly, make sure to note that this is a defect and needs to be corrected. 240 Volt circuits, including Multi-Branch circuits must be internally and externally linked.

Quad circuit breakers must be used in a service panel that is approved for tandem breakers. Look for this detail inside the service panel.

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