I need to run a 220 volt line from the main panel inside the house to the back yard and terminate into a switch disconnect for a split AC.

My main panel does not have a main breaker and there is only (1) slot available for a 110V breaker, so I thought tapping a sub panel ( switch disconnect with a 30 amp 220V breaker) would do the job.

I need some advise on how to do this. My plan is to tap the line for the sub panel to the incoming 220volt at the main panel and run the wire to the back yard to the sub panel (switch disconnect). This is a condo in the West LA area.

Thanks

You should call a licensed electrician for this job. You can not tap off the incoming wires to your panel. The wire going to your disconnect switch must have proper breaker size to protect the wire size your running.

Replace two of the existing 115 breakers with 2-in-1, slim line or piggy-back (different brands call them different things) breakers. This will free up an additional space for a double breaker for the AC.

DO NOT under any circumstances tap directly into the main 220v line in your panel! Instead, ask the hydro company to disconnect your power for a little bit, and install a thin 220v breaker designed to fit into the space of a 120v breaker.

Thank you for your quick responses. I am pretty comfortable dealing with the safety part as I have a related degree. But I am not in the wiring code industry so I am not familiar with wiring codes and therefore primarily concerned about meeting code.

hkstroud, for the 2 in 1, I suppose you are referring to a type of breaker that can take (2) wires for its output terminal. I believe Square-D has this type. For a piggy back breaker where there are (2) ckts in one breaker, is this pretty much universal or does this also depend on the mfg the panel?

Thanks

Banyan, what brand and model is your panel?
I assume there is a remote main disconnect since you say there is no main breaker and are in a condo. NO reason to get the POCO involved to install a breaker.

BTW, what is your "related degree"? That is a curious term for something related to the trades.

Oh, yeah, I have a bachelors in electrical engineering so I am very handy doing electrical work around the house, though as I said, I am not in the wiring code industry so I am not comfortable in that area. I do not want to do wiring on my condo, though safe, it might not meet code. I do not want to have any issues if I decide to sell it someday. I am actually installing a split AC.

Let me get more info on my panel. This is not my primary residence so I will have to go and look. I agree, there must be a main disconnect closer to the meter.

No offense, but an EE degree is about as helpful in building wiring as a calculator. You might use it once in a while, but for the most part is a useless tool.

Let us know about the panel.

I get the impression that the condo is your residence and the house where you are doing work is a single family residence. Is that correct? The thin breakers are just half the thickness of regular breakers so you can fit two in one slot. Breakers have to match the panel

No worries. I am not in the building wiring business as I said, but you asked... I still need to get the info on the panel, but, looks like the tandem (piggy back) solution is a viable one...

Thanks

Quote:

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Originally Posted by banyan

no worries. i am not in the building wiring business as i said,

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Wiring up an A/C unit is building wiring though. You don't have to be in business to do the work.
I was just making an observation. Too many EE's think there is some strong connection between their field and electrical work. There is not.

hkstroud:
You go it the other way. I am doing the work on the condo. Got it about the breakers... thx