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I am trying to understand the advantages of using a 2 pole circuit breaker. I mean when the 2nd pole is used in the Neutral line in a single phase 230VAC system. Normally they cost more so they must have some advantages over the single pole circuit breaker. So please explain to me the actual advantages of using 2 pole circuit breakers in a 230VAC L and N lines.

The answers I found are mostly related N.American electrical systems which are 120 or 240VAC, so those are different than European systems. I also know there are regulations to use them depending on the installation area and the type of protection sought but I want to given the option of choosing one, which one should I be using.

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  • \$\begingroup\$ N.American uses two phase system, where each wire is live. \$\endgroup\$ – Marko Buršič Mar 7 at 8:48
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Breaking both lines offers more safety during hands-on service of equipment in case the Neutral V is 10% of line voltage from heavy loads on other breakers. which is the worst case as I recall for residential wiring.

It also protects users from faulty reversed lines from inexperienced previous owners or contractors without a license. It happened to me once with our previous house that had 50 pot-lights added to the house and when I was installing a 2way stair switch I found wiring errors. Buyer beware, even inspectors can't check everything. It took me a week to sort out the wiring in the attic with all the potlight ceiling wiring buried in blown insulation. The risk of shock could be reduced with a double breaker here, but in North America, it doesn't happen unless its a 2 line 240V appliance. But as it happened when I saw the spark after removing the stair switch ground wire, I knew what to expect. So a double breaker would not have been useful as the symptom would have been masked. THe switch was connected between Hot and ground and Neutral was wired to the switch box. sigh.

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  • \$\begingroup\$ this is what I am failing to understand. If someone has connected the L and N in reverse order how does that affect. If I wire a socket in reverse order and the socket is not grounded. Now I touch the socket N which is actually connected to the Live wire so I get a shock but the current is still flowing through the L phase so the single pole breaker installed on the live phase will trip. How does the second pole of the breaker help? Sorry if I am asking a stupid question. \$\endgroup\$ – E-curious Mar 7 at 9:21
  • \$\begingroup\$ Since every supply has a return path, a dual breaker cuts both paths. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 7 at 9:23

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