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I just moved into a 2 bedroom apartment and am planning ahead for summer. While figuring out the breaker box so I don’t put more than one window a/c on a particular circuit I found out all of my 120v outlets in the living room (6 of them) somehow share a double pole breaker (240v and shows 15 on each of the connected breakers) with my 240v air conditioner outlet in the living room. The voltage is correct on all of the outlets but my question is with everything wired this way with an air conditioner running along with tv/internet/sound bar, am I going to run into issues with the double pole breaker tripping or should it be able to handle the load? Is this safe to have it like this? I’ve moved around in the same building and in other apartments in the same building that circuit breaker was always only for the air conditioner outlet.

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    What's the current rating on the A/C specs plate? Or the A/C model or can you post a picture of the plate? What other things will you plug in to those six outlets? Just those electronics? Not a vacuum for example?
    – jay613
    Mar 23 at 7:43
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    Yes, how many amps does your A/C pull? Mar 23 at 11:37
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    @jim Stewart the op stated 240v ac and the 120 receptacles on the same line MWBC not a split buss issue.
    – Ed Beal
    Mar 23 at 22:17
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It's fine; see what Ed says. What Ed is saying is that a circuit serving 120V loads on both legs and also 240V loads is perfectly fine, as long as the circuit breaker has "common trip". That's so if 120V loads trip one leg of the breaker, the whole circuit gets knocked out - if you left the other leg energized, power would leak into the tripped leg via the 240V loads).

You need to look at how much energy the TV, internet and sound bar take. Most people have no earthly idea how much energy devices take, so just read their labels/nameplates. If necessary, skill up on what amps, watts and VA are.

And after that, take a hard look at those air conditioners. Nowadays air conditioners are so efficient that they don't need 240V anymore. So I would take a hard look at the SEER numbers of your existing A/C vs new ones, and work out the energy costs of each. Hopefully you are not buying yourself new air conditioners every year, but giving the money to the power company instead of the appliance store.

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It sounds like you have a multi wire branch circuit, these were more common prior to the requirements of GFCI’s.

NEC 210.4.C states to supply line to neutral loads. however exception #2 comes into play when all ungrounded conductors are opened simultaneously by the branch circuit over current device.

Then exhibit 210.2 shows a duplex 240 / 120 receptacle.

I have run into issues with what you have where it was ok in 1 county cross a bridge and a violation in another. (This was prior to the mandate of MWBC had to have handle ties or be common trip). So the answer I could give is the NEC has allowed But the local jurisdiction has not in 1 town across the river it was ok.

What will be the limiting factor the size of the ac unit. If it is a 12 amp load that would be the max load for the circuit. Looking at 50% fixed equipment rule. at 50% is normally the max, I have seen a renter win with the fire marshal (in court) that the AC was temporary equipment so the 50% rule did not apply because in my area AC is not needed very often usually less than 3 months and a temporary window unit is not fixed equipment so he was using under 80% and it was not a electrical/fire code violation the judge agreed.

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