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Need help installing a sub panel outside off the main for multiple A/C units

Need help installing a sub panel outside off the main for multiple A/C units

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  #1  
Old 11-13-12, 08:41 AM
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Need help installing a sub panel outside off the main for multiple A/C units

Hi everyone and thank you in advance for the great help offered here!

I currently live in Puerto Rico and houses here are contructed of concrete walls and roofing.

My project consist of adding a sub-pannel to feed 3 A/C units that are located on my roof. I would also like to connect a security flood lamp to it and future expansion for another 2 A/C.

I am including pictures of the main feed that is on the outside wall with the power meter.

I am planing to feed the sub-panel out of the main. The wires will need to run along the outside wall to the roof, and continue in the roof to a central location in the roof that has about 3ft high and 5ft wide concrete wall.

What size (amp breaker), wiring (#8 or #6), and type of conduit should I use?

I am a handyman and are confortable with doing this job.

Thanks in advance.
 
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  #2  
Old 11-13-12, 09:47 AM
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We would need to know the ratings of the A/C units before the feeder could be sized. You should also do a load calculation before you attempt to add that much load to the service to see if it is adequate.

You will not be able to come off the main breaker next to the meter.
 
  #3  
Old 11-13-12, 09:50 AM
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That circuit breaker you are showing us is a 100 amp main disconnect. You can not connect your sub panel there. You must go inside to your main panel.
 
  #4  
Old 11-13-12, 11:07 AM
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The main disconnect shown in the picture is a 200amp. I have no other choice but to do it out of the main as the breaker box is installed in a wall that is in the middle of the house.

The A/C's are 8amps, 11amps and 14amps. Future A/C's would be of 11amps each.

So;
8, 11, 14, 11, 11 for all five A/Cs
 
  #5  
Old 11-13-12, 11:22 AM
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I have no other choice but to do it out of the main
Then the main would have to be replaced with a Service panel with room for breakers for each subpanel or a subpanel added next to it and the existing building subpanel connection moved to the new subpanel. The existing main panel can't be added to.
 
  #6  
Old 11-13-12, 06:52 PM
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I believe insulation piercing tap connectors could be used to tap the existing conductors on the load side of the GE 200 amp breaker, but the existing gear appears to be recessed in the concrete wall. I see no easy way to exit the disconnect enclosure without jackhammering the concrete wall. If you can exit the disconnect box, install a 100 amp NEMA 3R panel right there adjacent to the main disconnect with a 100 amp main breaker. I'd tap the service conductors with #3 THWN. This is provided that the 200 amp service can handle the additional load. You still need to do a load calculation before starting.
 
  #7  
Old 11-15-12, 04:22 PM
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Ok, I am back in business. I found a 1 in conduit that goes from the sub-panel to the roof and is empty. There is also room in the sub-panel to put a double breaker.

The run is about 90ft long.

So what wires should I use #6 or #8 for load and common? Ground #10?

What about breaker size on sub-panel A and A/C loads?

Thanks in advance!
 
  #8  
Old 11-18-12, 06:40 AM
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Can someone help determine the breakers and wiring size???

I just need the wiring size and breakers recommendations, anyone please?
 
  #9  
Old 11-21-12, 08:32 AM
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I just need the wiring size and breakers recommendations, anyone please?
15A, 15A, 20A, 15A and 15A. All 4 15A circuits can be pulled in #14. The 20A circuit should have #12.
 
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