2 different circuits sharing a ground?

Reply

  #1  
Old 04-03-11, 03:01 PM
Member
Thread Starter
Join Date: Jan 2011
Location: usa
Posts: 35
2 different circuits sharing a ground?

I'm wiring a bathroom exhaust fan that came as a combo light/fan. I was initially going to have separate fan and light fixtures. The way the wiring played out was that the fan was going to be on the bathroom circuit and the light on another. With this combo unit I can still wire the fan and light on separate circuits as initially planned "IF" the ground can be shared. Is that ok and within current NEC? The wiring will be inspected a couple weeks.

Thanks
Mark
 
Sponsored Links
  #2  
Old 04-03-11, 03:08 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,907
Upvotes Received: 16
Originally Posted by wirezcrossed View Post
I'm wiring a bathroom exhaust fan that came as a combo light/fan. I was initially going to have separate fan and light fixtures. The way the wiring played out was that the fan was going to be on the bathroom circuit and the light on another. With this combo unit I can still wire the fan and light on separate circuits as initially planned "IF" the ground can be shared. Is that ok and within current NEC? The wiring will be inspected a couple weeks.

Thanks
Mark
Sure, the ground wire can be shared. It sounds as if you'll be using a 3 wire cable to wire the combination unit, such as 12-3 or 14-3 romex. That one grounding conductor in the cable can be used to ground both the fan and light.
 
  #3  
Old 04-03-11, 04:17 PM
Member
Thread Starter
Join Date: Jan 2011
Location: usa
Posts: 35
thanks.
I'm actually using 14-2 & 12-2 which is already in place, if I switched to 3 wire cable it will just cause more work/$ for me. This will also not be a multi branch circuit as I will be using 2 separate breakers, a 20A bathroom circuit running the fan and a 15A 'other/lights' circuit running the light. Since the fan and light are in the same metal box (literally) I will have to share a ground between them, which I can do I think but just want to make sure.
But I cannot and will not share a neutral.
 
  #4  
Old 04-03-11, 05:08 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,841
Upvotes Received: 6
It would be much easier to add the fan to the circuit with the lighting. Why are you trying to use 2 circuits?

The fan/light junction boxes are very small so the less wires or cables the easier it will be.
 
  #5  
Old 04-03-11, 05:38 PM
Member
Thread Starter
Join Date: Jan 2011
Location: usa
Posts: 35
I agree but wiring is in place based on previous idea.
The reason I'm using 2 circuits is because I initially was going to have a light fixture and then a few feet away have the exhaust fan and have already ran the wiring. I came across a combo light/fan unit that looks good and serves both functions. The fan was going to be on the 20a bathroom circuit due to where the switch was going to be and location of wiring made it easy. The light, same thing, ease of where the switches are and location of wiring.
I have ran wire to the fixture with 14/2 from the light switch (power supply, single pole and only room for a 1 switch box due to stud location) and ran wire to the other switch for the fan control about 5 ft away near the vanity.
I want the fan to be able to run while the light is off, will that happen with only using 14/2?? If the light switch is off will there still be power to the unit that will allow the fan to be controlled from another switch?
I don't want to go out and buy more/differnt wire and rerun it if I don't have to.
 
  #6  
Old 04-03-11, 06:24 PM
Member
Join Date: Feb 2010
Location: United States
Posts: 461
As previously stated, you are going to have a VERY hard time trying to terminate 2 seperate cables in that fan/light junction box. Its usually very difficult to terminate a single 12/3 or 14/3 cable. i would run a new 14/3 or 12/3 and use a switch over switch at the location where it will be switched from.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes