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#100401 - 11/16/06 03:03 PM Date of adoption?
VAElec Offline
Registered: 07/26/05
Posts: 49
Loc: Sterling, Virginia, US
Without tracking down previous editions of the code and referencing them, is anyone aware of a method to find out when a section of the code was adopted/amended? Example I saw today that brings this to mind: 3-phase 4-wire delta-connected panel. High leg was marked orange (good per NEC 384-3 (e) '99), but landed on C phase (bad per NEC 384-3 (f) '99). Don't know when the panel was installed but would say within the last 20-30 years. Was landing the high leg on anything but B phase ever acceptable (I'm sure it was at some point but that's that whole me assuming things problem). But the main question is when we are asked to “take a look at something” and it is to code but for one small thing, how do we figure out if it was acceptable at some point. I mean other than asking the question here.
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#100402 - 11/16/06 04:50 PM Re: Date of adoption?
Tom Offline
Registered: 01/01/01
Posts: 1044
Loc: Shinnston, WV USA
I really don't know of any way of checking. I know that some utility companies require the high leg to be C phase in the meter. In the panelboards,

B phase gets the extra bracing so putting the high leg anywhere else could be a problem.

Looking at my oldest code book (1978) 384-3(f) "...The B phase shall be that phase having a higher voltage to ground."
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#100403 - 11/16/06 07:26 PM Re: Date of adoption?
ShockMe77 Offline
Registered: 06/11/05
Posts: 821
Loc: Rahway, New Jersey
I've come across existing installations where the high-leg is on the 'C' phase alot. I'll have to check my POCO specs book (PSE&G) and see if they're required like that around here. I know it's not what the NEC calls for, but most of the high-leg 3-phase services are identified with red tape, not orange.
#100404 - 11/17/06 07:25 AM Re: Date of adoption?
pauluk Offline
Registered: 08/11/01
Posts: 7520
Loc: Norfolk, England
Looking at my oldest code book (1978) 384-3(f) "...The B phase shall be that phase having a higher voltage to ground."

There's no 384-3(f) in the 1971 NEC, nor can I see any other applicable reference within article 384.

200-6(c) in 1971 covered general identification of the high-leg:

Where, on a 4-wire delta-connected secondary, the midpoint of one phase is grounded to supply lighting and similar loads, that phase conductor having the higher voltage to ground shall be orange in color or be indicated by tagging or other effective means at any point where a connection is to be made if the neutral conductor is present.

The part I've quoted bold has the "changed from previous edition" line alongside. I seem to recall a discussion a while back in which it was decided that 1971 was the first time orange was suggested specifically.

Still nothing about the high leg having to be B phase that I can find though.

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