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After 2 hours of working on it. I was able to replace the old breaker with Schneider Din Rail 125A breaker that directly feeds the Siemens panel with 6 GFCI breakers. See: https://imagizer.imageshack.com/img923/1584/3pqfvs.jpg The remaining 1-pole breakers below the above (now subpanel to a 60A Siemens GFCI load side) would be slowly replaced with Din rail because they are individual 1-pole breakers that would only trip 1 phase with remaining 1 phase hot. But then what is the problem if I won't replace them anymore (it would take too much work and interruption of power which my elderly co-occupants won't like). Note in fuses, only one phase disconnects, so is there any serious problems if only one breaker trips (out of two 1-pole) if there is short circuit or overload?

original message:

I realized a huge mistake. In our main panel, 32 pieces of individual 1-pole breaker was used for 240v 2-pole phase to phase. See

enter image description here

We thought the external handle can trip the other partner. But it couldn't. The internal tripping mechanism can engage even if it's in On position, the external handle can't push the other to Off. So one leg is always hot. In 2-pole breaker, there is an internal common trip. Hence I will just remove the entire plug-in bus bar & breakers and replace them with Din Rail breakers that will feed off the 60A GFCI in the Siemens main breaker. Most new condominium & houses use din rail now in the country and I don't want to buy new set of 2-pole plug in breakers to replace the 32 pcs.

Now my question. Should I use din rail enclosure inside the original panel or just the din rail breakers (like this):

enter image description here

Or is it better to just remove the old panel case itself? But it looks hard, so I plan to just removed the bus bars and breakers leaving panel case intact.

After the plug in bus bar was removed. How can I put new screw over metal that is encased in concrete. Must we drill all the way to the concrete and put screw anchor in the concrete or is there a screw that can use the metal chassis itself without digging deeper into the concrete?

  • 1
    Why can you not get 2-pole breakers for the existing panelboard? – ThreePhaseEel Feb 10 '19 at 1:45
  • Din Rail is nicer, neater. Bus bar is just so bulky. Remember it will be subpanel of the 60A GFCI output only. So I just need 6 or 8 breaker panel. The extra bus bar with 10 extra breakers are not needed. – Jtl Feb 10 '19 at 2:28
  • another major reason in addition to the above is the panel is only locally manufactured, the bus bar stubs are not even centered unlike Siemens panel bus bar stubs which are very aligned. And I suspect the locally made panel has thinner stubs hence I can't trust it. If it is an original US made GE panel. I could have replaced them with 2-pole breakers. – Jtl Feb 10 '19 at 3:17

I would mount the rail in the enclosure and snap them on. At industrial sites we do use din rail in motor control systems all the time having it in a metal enclosure provides another layer of safety.

  • what "enclosure" were you referring to? you mean mount the rail in the original plug in panel enclosure or the din rail plastic enclosure then put them in the original plug in panel? – Jtl Feb 12 '19 at 0:54
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    You stated taking the buses out and installing din rail breakers, this would put them in a solid enclosure. – Ed Beal Feb 12 '19 at 2:33
  • Ok the rails would be screwed directly to the empty original panel.This would become subpanel of load side of 60A GFCI breaker.However, the din rail main breaker will b connected to d Siemens main panel.It's to replace original main breaker.So it makes sense to put d main breaker in plastic enclosure to prevent accidental contact between the wires and the orig main panel since d main breaker s not GFCI protected. concern is f d plastic enclosure s safe to use wit 125A din rail or could it melt from heat see pic of my Schneider breaker/plastic case imageshack.com/a/img921/316/ZrSM2C.jpg – Jtl Feb 12 '19 at 22:58
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    I would say the wire bending space looks a bit tight to be totally code compliant for example a #1 copper wire needs 3 inches from the edge of the terminal to the box wires. Below 10awg are not specified see table 312.6 of the NEC for other values. – Ed Beal Feb 13 '19 at 0:29
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    I rarely see breakers get hot enough to damage the enclosure except for brands that have known problems like FPE stablock. Other than the wire bending space I would think it would work. – Ed Beal Feb 13 '19 at 14:06

Are you in the US? If so, you cannot legally use those DIN rail mounted breakers in that panel (or elsewhere for that matter). They must have an "Interrupting Capacity" (IC) rating that is equal to or greater than the available fault current at your building. Those cheap DIN rail breakers from China that you likely bought over the internet are not listed by an acceptable NRTL (Nationally Recognized Testing Lab, like UL) with an acceptable IC rating.

Besides that, how would you get power TO the DIN rail mounted breakers at all, if you don't use breakers in the panel that you have?

I would just get 2 pole breakers for the panel that you have.

  • 1
    I live in the Philippines. I just bought the Schneider C120 2-pole, the interruption current is 20kA, even twice that of plug-in GE breaker schneider-electric.com/resources/sites/SCHNEIDER_ELECTRIC/… In the Philippines we can combine regular breakers with din rail. I have a main disconnect see imageshack.com/a/img923/5663/2HKWhz.jpg where I'll power the din rail panel. My question is whether to use din rail enclosure or directly plug the din rail breakers at original panel after removing the plug in bus bar from the panel. – Jtl Feb 12 '19 at 0:25

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