upgrade exsisting sub panel in garage questions ???


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Old 12-17-16, 05:48 AM
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Question upgrade exsisting sub panel in garage questions ???

I have a existing subpanel in garage with 10/2 ufb with ground from a 30 amp breaker in house to two 15 amp in garage and need 60 amp. could i run another 10/2 out to garage hook the the 2 feeders to one 60 amp in the house and be able to supply 60 amp sub panel in garage. i guess the big question is two 10 gauge wires equal to one 5 gauge.
any ideas

Trying to do this on the cheep but safe at the most i would have powered at one time out there would be a 2.5 hp air compressor, stereo and 6 or so shop lights.. is this possible?
 

Last edited by Jeff Dang; 12-17-16 at 05:49 AM. Reason: forgot spell check
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Old 12-17-16, 06:16 AM
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Welcome to the forums! Is the garage detached or attached? You can't double up any of the wiring in order to achieve proper size. It would be best to abandon the 10-2 and run a new 6 AWG in 4 wire (for less than 75') to the panel with breakers on both ends. Does your subpanel have accommodations for a main breaker? Is there conduit between the panels?
 
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Old 12-17-16, 06:56 AM
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detached it is about 30 feet away yes to the conduit, i dont have the sub panel yet but i do have 100 ft of free 10/2 ufb wire to use up
 
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Old 12-17-16, 07:39 AM
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I should have incorporated a sub question. What is the diameter of the conduit?

Good load center. Check with local authorities to make sure you can use a main lug center. Murray 60 Amp 2-Space 4-Circuit Surface Mount Main Lug Load Center-LC002GSU - The Home Depot

You will need to run 4 wires, and I suggest using #6 THHN. 100 ft of each (RGBW) will run about $65. UF cable is a bear to run in conduit.

You will also need a separate grounding bar to be attached to the panel, and 2 grounding rods and #6 bare copper to run from the panel continuously to the grounding rods.

Use your 10-2, but not here, as it doesn't have the ampacity you need with the 60 amp circuit.
 
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Old 12-17-16, 08:06 AM
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I would go with a main breaker panel kit such as:

Eaton 100 Amp 10-Space 20-Circuit Type BR Main Breaker Renovation Panel Load Center Value Pack (Includes 2-BR115 and 1-BR230)-BR1020B100SRNV - The Home Depot
or
Eaton Cutler-Hammer 100 Amp 20-Space 20-Circuit Indoor Main Circuit Breaker Panel Value Pack-BR2020B100V4 - The Home Depot

They cost a little more but not that much more since they include some branch circuit breakers and they are good future proofing should you ever need more breakers.
 
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Old 12-17-16, 08:43 AM
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First things first. As asked what is the size of the existing conduit between the house and garage? You may not even be able to install larger wire. Code limits wire size to a percentage of conduit fill.
 
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Old 12-17-16, 08:58 AM
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You may only have one feed to a separate building (225.30)
 
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Old 12-17-16, 09:16 AM
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If you do have large enough conduit to handle larger wire use the existing #10 to pull in the new wire as you pull out the #10. Or pull in a pull rope when pulling out the #10. Just one of those things that will make you cuss if you forget to use the old wire to pull in a rope or the new wire.
 
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Old 12-17-16, 10:24 AM
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Also what kind of conduit. If it is EMT for all practical purposes it can't be reused.
 
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Old 12-17-16, 04:54 PM
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I have a existing subpanel in garage with 10/2 ufb with ground from a 30 amp breaker in house to two 15 amp in garage and need 60 amp.
The 10-2 UF-B cable was never code compliant to feed a subpanel where you are using single pole breakers for 120 volt lights and receptacles. You definitely need to replace it with a 4-wire feed. Obviously this was never inspected. Your old setup was using a bare ground wire as a current carrying neutral conductor.
 
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Old 12-18-16, 08:21 AM
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The 10-2 UF-B cable was never code compliant to feed a subpanel where you are using single pole breakers for 120 volt lights and receptacles.
May be, may be not. Could have been set up as a 120V only feed with the neutral/white being used as a neutral and not a hot. The OP never said if the #10UF was supplying 120/240V at the garage or just 120V and that the 30A feeding breaker was a single pole or double pole. The odds are you're correct.
 
 

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