I want to install central air conditioning in my home but my current service is 100 A, I believe.

If I were to upgrade to the 200 Amp service, could the breakers be configured where I have two 100 Amp main breakers? One will be the already existing breaker box servicing the house as usual, and the other would be just for the central air conditioning.

Is this possible to configure like this?

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    The 100 amp main panel is at capacity with an electric water heater, electric stove, electric dryer and electric washing machine. Adding an AC unit to that would just blow the main breaker every time from what I've researched. I live in Trinidad and Tobago, feeder wires are just like in the US, 220V in and split into 110V by the breakers. I want to know if it would be possible to add another 100 amp main breaker from the feeder wire to have 200 amps in total. Or will I have to foot the bill of changing out my main breaker – ForeverLearningJP Jul 21 '20 at 14:25
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    @ForeverLearningJP that mains breaker might very well be in the control of your power company. Which is who you should be asking ! – Marcus Müller Jul 21 '20 at 14:31
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    Not at all, the power company here stops at the meter, they tell us to install our own stuff and they will inspect it afterwards, I would've been glad to have them do it, but I'm here – ForeverLearningJP Jul 21 '20 at 14:35
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    "they will inspect it afterwards" great, so ask them what would pass their inspection. Also, really, if there's no circuit breaker before your 100 A circuit breaker you can't replace that yourself, without almost certainly hurting yourself or damaging property of the power company. Get help of an electrician. He knows the laws regarding electrical installations of where you live. – Marcus Müller Jul 21 '20 at 15:02
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    @JimStewart I'm installing a 9000btu mini split unit. I don't want to have it on a separate meter. I'm just trying to find the lowest cost solution to get power to the unit – ForeverLearningJP Jul 21 '20 at 16:22

It is possible, and not uncommon.

You'd have to splice it in one of the boxes before the breaker, after the meter.

You can cut off power by removing the meter from its socket, which breaks the seal.

I wouldn't touch it unless I first had a discussion with the company and an electrician.

  • You can cut off power by breaking the seal and removing the meter, but it's not highly recommended. Used to work with US REMCs - they didn't like it much. – FreeMan Jul 21 '20 at 16:32
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    Found out today that they did this for my electric dryer so I talked with power company and they said that they will send an electrician to reconfigure it to a second main panel for me. Provided that I have the parts. – ForeverLearningJP Jul 23 '20 at 1:43

Not necessary.

All you need to do is get your 200A service, feeding a new service panel that is a 200A “main panel” with main breaker. Then inside this panel, stick a 100A breaker, then run 1 AWG aluminum wire from there to the old 100A panel.

The old panel must be re-configured as a subpanel, which requires removing all ground wires from the neutral bar, putting them on an accessory ground bar, and removing the neutral-ground bond.

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