Single phase panel improperly wired as 3 phase

Status
Not open for further replies.

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
On a single phase, or three phase, you can have as many ungrounded as your heart desires per grounded conductor, as long as properly sized
I thought I addressed that situation for the OP. I stated if he had a #8 neutral it would be okay in his scenario. Also as Gus stated, how do you disconnect all ungrounded conductors simultaneously when there are more than 3.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Here it is

210.4 Multiwire Branch Circuits.
(B) Disconnecting Means. Each multiwire branch circuit shall be provided with a means that will simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.
 

mcclary's electrical

Senior Member
Location
VA
I also say that you cannot have 3 hot conductors with one neutral on a single phase service, however if the neutral were sized for 40 amps you probably can get away with it. Seriously, most inspectors probably won't go for that either so--- 2 hots to one neutral. On a 3 phase system you can have 3 hot conductors to one neutral.

I was referring to this statement
 
My dad was a cable splicer in the old "Ma Bell" days. I remember him using the term "slate" as one of the wire colors.

Yep, it blue / orange / green / brown / slate (there is no gray). Or, in Bell abbreviations- Bl O G Br S. Major colors are white / red / black / yellow / violet (or W R Bk Y V). The V/S pair was always the lonely one, being the 25th. The codes kind of stick with you after a while, I still confound people by using them. (And right now I'm trying to get some coworkers to use the W/Bl pair before the W/G one....)

I also draw contacts with an X on the line as normally-open and a bar across it as normally-closed.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Ever seen a 4 pole breaker?
Yes, if you count the 4-pole (2, really) main breakers, and two instances of what look like 4-poles: some 3p shunt-trips and the old "Delta" breakers.

Any of the above can become a donor for those times when you need a 4-pole-sized handle tie. I can't promise your inspector will like it, though.
 

Split Bolt

Senior Member
This thread has gone WAY off subject and I don't think anybody even saw my scenario on post #18. I'm really concerned about the dangers of potentially overloaded neutrals that the writer of the OP said he has done on 95% of his jobs! Please go back to re-read #18 and let me know if I'm just worrying too much. I worked for a company that fired an electrician for doing this!
 

mxslick

Senior Member
Location
SE Idaho
This thread has gone WAY off subject and I don't think anybody even saw my scenario on post #18. I'm really concerned about the dangers of potentially overloaded neutrals that the writer of the OP said he has done on 95% of his jobs! Please go back to re-read #18 and let me know if I'm just worrying too much. I worked for a company that fired an electrician for doing this!


I think you are worrying too much. :grin:

First off, you (and a LOT of others) are assuming that there are MWBCs in use and the OP never said that.

Secondly, the inspector is full of it. Code does NOT prohibit what the OP described. Posts #2 and #3 already addressed that.

IF (and that's a big IF) the panel is wired in "full boat" style with MWBC's then yes there is a violation, but it is NOT as the inspector worded it.

Mike1061, tell the inspector to provide a Code Reference that specifically states what he wrote you up for. He won't be able to. Use the Section provided in post #2 to back up your position.

However, if this is wired with MWBC's with anything more than two circuits sharing one neutral, then you have some corrective work to do. But the inspector will still need to cite the proper violation.
 

kwired

Electron manager
Location
NE Nebraska
AFAIK you should be okay. It is when you have two or more nominal voltages in 1 building, ie: 208/120 and 480/277, that you have to identify which system is which.

210.5 Identification for Branch Circuits.

(C) Ungrounded Conductors. Where the premises wiring
system has branch circuits supplied from more than one
nominal voltage system, each ungrounded conductor of a
branch circuit shall be identified by phase or line and system
at all termination, connection, and splice points. The
means of identification shall be permitted to be by separate
color coding, marking tape, tagging, or other approved
means. The method utilized for conductors originating
within each branch-circuit panelboard or similar branchcircuit
distribution equipment shall be documented in a
manner that is readily available or shall be permanently
posted at each branch-circuit panelboard or similar branchcircuit
distribution equipment.

And even if he had two voltage systems he does not have to identify them with wire color, although it is the easiest and most common way to do it. He could tape them, tag them, paint them, or whatever. The only colors with restrictions to their use are white, gray and green.
 

mike1061

Senior Member
Location
Chicago
Sorry but this is way of topic.
What I mean is, I have a 1 phase, 240 volt, 100 amp residential circuit breaker panel. I used Black, Red and blue wires. Some branch circuits were Black and white, some were red and white, some were blue and white. Some shared a neutral, for example, Black, red and white, or Black, blue and white. Never would I use 3 ungrounded conductors with 1 grounded conductor, in a 1 phase panel.

My understanding was that the code called for Black, Red, and Blue (only) to be used as ungrounded conductors. I did not think there was a difference for single phase and three phase. That the blue could only be used in a 3 phase panel.
I'm looking now to see if I can find the artical I was thinking of.

Hope that was clearer.
Again, very sorry about the confusion.
Thanks Mike
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
As far as the _NEC_ is concerned, your install is just fine. The only _dedicated_ colors in the NEC are for grounded and equipment grounding conductors, and for the stinger leg if present. You could use just about any random colors you wish (other than the specifically dedicated ones) for the ungrounded conductors.

'Commonly' black, red, and blue are used for 208/120, and brown, orange, yellow for 480/277.

As others have noted, if you have multiple services in one building, you have to do something (such as use different colors) to differentiate between the two. You might be forced into a particular color code because of the rest of the installation.

Note, however, that some people really like the idea of a specific universal color code, so specific color codes often get amended into the code. Your inspector might very well be able to point to a specific local amendment that says that a single phase 120/240 system use red and black only.

-Jon
 

russ

Senior Member
Location
Burbank IL
Could this be an area that use's Chicago code?
I know there was talk of rewriting (C)(1) to say A phase Black, B phase Red, C phase Blue,
The way it's worded now nothing says single phase must be A Black and B Red.
It might be assumed that's what the intent was. The latest copy I have is 2008, it may have been updated after that.

18-27-210.5. Color Code for Branch Circuits.
(a) Grounded Conductor. The grounded conductor of a branch circuit shall be identified in accordance with 18-27- 200.6.
(b) Equipment Grounding Conductor. The equipment grounding conductor shall be identified in accordance with Section 18-27-250.119.
(c) Ungrounded Conductor(s). (1) Ungrounded conductors of branch circuits rated 150 volts to ground or less shall use the following color code: Black, Red, Blue.
The high phase of a center-tapped delta system shall be identified with red.
(2) Ungrounded conductor of branch circuits rated over 150 to ground shall use the following color code: Brown, Orange, Yellow.
 

Split Bolt

Senior Member
Sorry but this is way of topic.
What I mean is, I have a 1 phase, 240 volt, 100 amp residential circuit breaker panel. I used Black, Red and blue wires. Some branch circuits were Black and white, some were red and white, some were blue and white. Some shared a neutral, for example, Black, red and white, or Black, blue and white. Never would I use 3 ungrounded conductors with 1 grounded conductor, in a 1 phase panel.

My understanding was that the code called for Black, Red, and Blue (only) to be used as ungrounded conductors. I did not think there was a difference for single phase and three phase. That the blue could only be used in a 3 phase panel.
I'm looking now to see if I can find the artical I was thinking of.

Hope that was clearer.
Again, very sorry about the confusion.
Thanks Mike

Mike, Glad to read that! I guess I was thrown off by your choice of title! Maybe "Use of three phase colors in a single-phase panel" would have been better!:)
 

mcclary's electrical

Senior Member
Location
VA
Sorry but this is way of topic.
What I mean is, I have a 1 phase, 240 volt, 100 amp residential circuit breaker panel. I used Black, Red and blue wires. Some branch circuits were Black and white, some were red and white, some were blue and white. Some shared a neutral, for example, Black, red and white, or Black, blue and white. Never would I use 3 ungrounded conductors with 1 grounded conductor, in a 1 phase panel.

My understanding was that the code called for Black, Red, and Blue (only) to be used as ungrounded conductors. I did not think there was a difference for single phase and three phase. That the blue could only be used in a 3 phase panel.
I'm looking now to see if I can find the artical I was thinking of.

Hope that was clearer.
Again, very sorry about the confusion.
Thanks Mike

There's nothing wrong with what you did. He may think there is, but he's wrong
 
Status
Not open for further replies.
Top