Can I use siemens tandem qt breaker in g3030mb1200 panel

Install subpanel or tandem breakers:
http://waterheatertimer.org/Not-enough-space-for-circuit-breakers.html

http://waterheatertimer.org/How-to-install-a-subpanel.html

Gene

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Go to any home store and ask them, they will have the breaker or one to use as a replacement

He is correct. I'll not go into the particulars but the fact is, you have two separate circuits connected to the same breaker. Separate the two circuits by installing another 15-Amp breaker. Although I understand your situation, please understand wire gauge and electrical amperage are two different animals. Breakers are rated in Amperage and electrical conductors are sized by wire gauge. That said, the 20 gauge wire you speak of is actually a 12 gauge conductor and the 15 gauge wire as you say is a 14 gauge conductor. Have a good day.

The use of 2 15amp breakers first had meaning. If you can relocate with one tandem 15 amp it means that there will be no protection cuase the tandem tripping point does not count.

3200 watts or 1600 watts on each terminal.

Charlie,
If these tandem breakers are the separate 1/2 height breakers in the space of a normal breaker, then no, they can't fail internally to cause what you are describing. But if you have the kind that are permanently stuck together, then I can't say. But here is a simple test: Use a meter or a test light to confirm at the breaker terminals that turning off either one of the breakers still gives you power at both breaker output terminals. Now turn off BOTH breakers, and disconnect one output wire (being careful that the loose wire isn't going to touch somehting!), then turn on the breaker that still has an output wire connected - if the loose wire is live then you have a wiring error where both circuits are connected together downstream. If that is the case, then it may have been intentional as a way to "fix" a frequently tripping breaker by giving it a second chance each time it tripped! (This is a pretty far-fetched idea, but it may give you something to think about!) If it was me, I would just replace the tandem pair with a single breaker and put both of the output wires together on the single breaker.
Good luck! Be careful.

A Square D QOABB is a QO style circuit breaker, as determined by the "QO". A represents the number of poles; and can be 1, 2 or 3. This number also represent the number of spaces it requires in the panel (NOT the cover). "BB" represents the Amp rating of the handle. Common values are 15, 20, 30, 40, 50, 60, and beyond. A Square D QO3100 (3Pole 100A) is pictured below:




A Square D QOTXXYY is a tandem circuit breaker. "T" represents Tandem. "XX" is the amp rating of one handle and "YY" is the amp rating of the second handle. It occupies one singe slot in the panel (again, NOT the cover). It look like this QOT2020 (A single pole breaker with tandem 20 amp handles) below:


The clip under terminal screws engages the panel's "rail", and the other clip(s) must engage the panel's powered bus or "metal" strips as you called them. If you are installing a QO230, BOTH clips MUST engage. If only one engages, you will only have 120 Volts to ground, and may not be able to put the panel cover on.

I hope this helps and good luck!

While this may appear to be doable - the fact remains that the interior and enclosure are tested, approved and listed by UL / FM / etc. as an entire assembly. Taking from one and replacing with another results in a combination that was not listed.

If however, the enclosures of the two panels are identical - then I suppose I would consider doing the same thing. I would be sure to change out the panel cover so that the cat number and info matches the bus.

yes it will, you need to always make sure that you put the same brand in the panel box, good luck

See 60 Amp sub-panel image

Above image shows drawing of 60Amp sub-panel located next to main panel. Drawing shows #6 wire... 125' distance to garage calls for #4 wire. I ran #4 to my barn and have no problems.

Give thought to how many new breakers you want at garage.
See photo of subpanel that holds three 240V breakers

Using drawing as a guide. Replace existing 240Volt breaker with new 60 Amp breaker. Two hot wires connect to new 60 Amp breaker. Neutral connects to neutral busbar.

More space: You can free up space in main breaker box using a tandem breaker. Or by doubling up 2 lightly used 120V circuits onto one breaker. Do not double-up on 240 Breakers

Conduit: You want PVC conduit large enough to fit three #4 wires. Bigger conduit is easier to pull wires ... and maybe later ethernet wire, or alarm wire etc.

Ground wire: You can put a ground rod at garage and run #6 bare copper between sub-panel neutral-busbar and ground rod. Attach ground wire firmly with grounding clamp.

I want you to check with local electrical supply for exact code in your area concerning conduit requirements, grounding, and wire size. Tighten all lugs very tight against wire.