Replies

1. 
   BillHartmann | Sep 22, 2006 06:57am | #1

   While the equipment grounding conductor (EGC), aka "the ground" is bonded to the neutral at the main disconnect they serve two completely different functions.

   Inside the the house the egc's ownly purpose is to carry any fault current.

   And yes, metallic conduit can be used for the egc.

   "Why do electricians run serveral hots in conduit but only one neutral"

   Those are a special type of circuit called a "multi-wire circuit". The consists of 2 hots (120/240 residential) or 3 hots (3 phase) and a single neutral.

   The the 2 (or 3) hots are on different legs so that the neutral only has to carry the difference between the two hots.

   Not only does it say copper, but the fewer wires to get hot under load. Which has to do with computing derating factors when you have multiple circuits in one conduit.

1. 
   curley | Sep 22, 2006 03:11pm | #2

   I'm still confused. I know a large motor such as an AC comprssor is 220 and uses two hots and a neutral.

   the electrician wiring my house was pulling wire through the conduit. I thought I heard him say he could pull seven hots and only one neutral in a 3/4 in pipe. Why doesn't each hot require its own neutral ???So he was pulling seven hots and seven neutrals

1. 
   Boats234 | Sep 22, 2006 05:19pm | #3

   I assume your electrician is using a "shared neutral". As far as that 7-1 ratio... sounds a bit overloaded.

   I have no idea what the code is, but I've always used 1 neutral per 2 circuits.... each circuit has to be on a separate leg( 180 out) so as not to over load the neutral.

   One of the real electricians should be by shortly to cite the code.

   A shock hazard still exists on a de-energized circuit using a shared neutral.

1. 
   curley | Sep 22, 2006 05:51pm | #4

   Yea, the question is the sharing of the neutral between different circuits. Wish 4Lorin was available

1. 
   junkhound | Sep 22, 2006 08:25pm | #5

   Old code book, but 215-4 (a) allows:..... shall be permitted to supply 2 or 3 sets of 3 wire feeders....       which means one white neutral and 3 red and 3 black wires, 7 total.

2. 
   JohnSprung | Sep 22, 2006 09:16pm | #6

   Could it be that they're switch legs?  I pulled some stuff in the back yard, all on one circuit -- on the same breaker, where there's one green for ground, one white for neutral, a red that's always hot, a yellow that's the dimmer leg for some lights, and a blue that's a switch leg for some receptacles.  Each box has a hot receptacle, and a switched one.  

    

   -- J.S.

    

3. 
   BillHartmann | Sep 23, 2006 01:29am | #7

   "I'm still confused. I know a large motor such as an AC comprssor is 220 and uses two hots and a neutral."Not they use 2 hots and a ground.I think that he was talking about grounds.One ground can be used for any number of circuits. Just has to be sized to handle the single larges size circuit, because you are expecting to have multiple faults at anyone time.For a neutral if you used one to support multiple circuits than it would have to be sized to handle the total current for all of the hots. I don't think that the code allows for doing that, but I have never really looked for it.