neutral conductor - Electrician Talk - Professional Electrical Contractors Forum

chollapete · 06-20-2008, 06:58 PM

2008 NEC Handbook, p 30, Exhibit 100.11. Should one of the batteries in the fourth example have its poles reversed in order to make the labeled conductor a neutral point? As I see it as printed, DC voltages add in series, so the labeled conductor is actually at positive voltage.

nap · 06-20-2008, 07:01 PM

there is no neutral in DC voltage.

there is Positive and negative

any chance of showing the drawing? I don;t use the handbook and don't have access to one.

JohnJ0906 · 06-20-2008, 07:37 PM

Quote:

Originally Posted by chollapete

2008 NEC Handbook, p 30, Exhibit 100.11. Should one of the batteries in the fourth example have its poles reversed in order to make the labeled conductor a neutral point? As I see it as printed, DC voltages add in series, so the labeled conductor is actually at positive voltage.

I think you mean Exhibit 100.12.

Quote:

Originally Posted by 2008NEC

"Neutral point - The common point on a wye-connection in a polyphase system or midpoint on a single phase, 3-wire system, or midpoint of a single-phase portion of a 3-phase Delta system, or a midpoint of a 3-wire, direct-current system"

I'm not sure about the pole orientation part of your question.

chollapete · 06-20-2008, 07:59 PM

my only Internet now is EDGE on an iPhone. Can't scan and attach a drawing. Yes, I mean 100.12.

By "pole orientation" I mean: the figure shows two batteries in series, with a conductor brought out from between the two cells. They are calling that center conductor the "neutral point". (One of the other two conductors is connected to one cells positive terminal; the other conductor is attached to the other cells negative terminal.) To get something akin to a neutral, you could reverse the polarity of one of the cells, so the "neutral conductor" is now connected to both negative terminals and each of the other two is attached to a positive terminal.

Wish I could draw a picture--the concept of neutral point in a DC circuit doesn't grok for me.

nap · 06-20-2008, 08:20 PM

that is the neutral point.

My misreading concerning your post lead to my mistake and possibly the way I was taught.

if you can go to this link, I believe it shows what you are speaking of but with generators rather than batteries. Go on down to page 7.

Is this the same (other than the gens instead of batts)?