Basic wiring


  #1  
Old 02-20-03, 09:25 AM
ldavid
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Basic wiring

Hello, I'm wiring some lights off a 20 amp circuit. I am using 12 guage wire, but am unsure if I need to use 12guage grounding wire. A co-worker had told me that 14 guage would be fine. Any suggestions?
 

Last edited by ldavid; 02-20-03 at 10:01 AM.
  #2  
Old 02-20-03, 11:09 AM
S
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It would probably be fine in lighting circuit and they used to allow a smaller wire in grounds because direct shorts can draw hundreds of amps instantaneously, however, I believe modern codes call for the ground to be equivilent to the conductors in branch circuits. Remember the purpose, to provide a low resistance pathway back to the panel to carry enough current to trip a breaker or blow a fuse instantly in the event of a short. The better the wire the better it is going to work. When you say provide a wire are you using cable or pipe? The cable (romex) should have the wire in it and if it is pipe that can be the grounding conductor also.
 
  #3  
Old 02-21-03, 06:36 AM
jjrick
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Sberry27 is talking about the grounded wire, not the grounding wire...there is a difference. Your grounded/white wire carries current back to your panel and your grounding wire carries current to earth in the event of a fault. Either way the NEC says it must be a 12 gauage wire if you are on a 20 amp circuit. Also remember that in residential you are only suppose to load the circuit to 80% max or 16A for a 20A circuit.

If you are using standard NM cable then all the wires will be either 12 or 14 gauage and if you need to tie a grounding/green wire to the bare wire in your cable for extension then it should be a 12 gauge wire.

JJRICK
 
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Old 02-21-03, 06:52 AM
J
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I am quite certain that sberry was indeed talking about the grounding wire.
 
  #5  
Old 02-21-03, 07:44 AM
ldavid
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Thanks for the reply. I am using bx, and planned to run 12 guage, (including ground) through it. I wanted to run a ground wire to connect to lighting fixtures. This brings me to another question. On another 20 amp circuit, there was a 15 amp light switch, and 15 amp receptacle. This concerned me, so I replaced them with 20 amp rated devices. Was I correct in doing so?
 
  #6  
Old 02-21-03, 02:58 PM
J
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You were correct to do so. But you would have been also correct if you had not done so. 15-amp receptacles and switches are allowed on 20-amp circuits.
 
 

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