New NMB 14-3 wiring color coces explained (C) Daniel Friedman Guide to Building Electrical Wiring Color Codes
     

  • ELECTRICAL WIRING COLOR CODES - CONTENTS: Electrical Wiring Color Codes & Conventions for 120V or 240V A/C Circuits in Buildings - Tables of Electrical wiring color code conventions for 120V & 240V AC circuits in buildings in the U.S., Canada, the U.K. & the I.E.C. Included is a chart of wiring color code abbreviations.
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Electrical wiring colour codes:

This article describes the electrical wiring color code conventions for 120V or 240V AC circuit wiring in buildings in Canada, the U.S., the U.K. and the I.E.C. Quoting from authoritative codes & standards for each region we provide a table summarizing the current and prior wiring color code conventions used by electricians in building wiring.

For each color code table we include authority citations and links to sources of codes, books, standards and wiring guidelines. We point out with photo-examples that while wire color code theory is nice and all that, in the real world of working on existing buildings, wires are not always reliably color-coded and colors may in fact be impossible to discern. Some of the wire color images here were adapted from data provided by the Malta Resources Authority's excellent document on Harmonisation of Wiring Colour Codes - cited below.

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Building Electrical Wiring Color Codes & Conventions for 120V or 240V A/C Circuits

New NMB 14-3 wiring color coces explained (C) Daniel FriedmanThis new type NM-B 14-3 electrical wire has color coded conductors that are easy to spot and understand:

  • Black - use for line voltage or "hot" wire
  • Red - a second line voltage or "hot" wire
  • White - neutral
  • Bare - protective ground

But as we will illustrate below, on some older buildings spotting any color at all in the wiring insulation or jacket can be difficult or even impossible. Here are links to the electrical wiring color code conventions used by various countries.

Article Contents:


American flag

120V / 240V A/C Electrical Wiring Color Codes & Conventions: U.S.

Wire Insulation Color Alternative Wire Colors Label Function Comments
Black
Black wire
 
L
Line voltage, single phase Abbreviation: BK
Black
Black wire
Brown
Brown wire
L1
Line voltage, 3-phase Abbreviation: BK, BN, RD
Red
Red wire
 
L
Line voltage, single phase, second "hot" wire
Often used to indicate switched power
Red
Red wire
Orange
Orange wire
L2
Line voltage, 3-phase Abbreviation: RD
White
White wire
Gray
Gray Wire
N
Neutral

In wiring a switch the electrician may use the white wire as a second hot conductor and will mark each end of the wire with black electrical tape - shown below.
White black wire

Abbreviation: WT, GY

Blue
Blue wire
Yellow
Yellow wire
L3
Line voltage, 3-phase Abbreviation: BL, YL
Green
Green wire
 
PG
 

Protective ground wire

Abbreviation: GN

Green + YellowGreen Yellow Wire  
PG
 

Protective ground wire

Abbreviation: GN+YL

Bare
Bare copper wire
 
PG
 
Protective ground wire, no insulation
Orange
Orange wire
Yellow
Yellow wire
L
 

"Excepted voltage", these wires may be hot when main disconnect is switched off"

Abbreviation: OR, YL

Notes & wiring color code standard sources:

1. National Electrical Code 2011 (NEC) - see http://www.nfpa.org/ (adopted in all 50 U.S. states)
2. UL508A, Section 66.5.3 & 66.9
3. NFPA 79, Chapter 13 - see http://www.nfpa.org/

Some sources include red with white tracer line = switched neutral


Antique wiring color coded in jackeing or insulation (C) Daniel Friedman

On older wiring such as this rubber and fabric-jacketed household wiring from a U.S. home, figuring out what the heck the wire colors are can itself be a challenge.

Look closely at the fabric covering of the two wiring strands in our photo.

The upper wire is the "white" or neutral wire.

The lower wire, whose fabric insulation is black with red and white tracer threads is the "black" or hot wire.

But sometimes there is no clear color distinction between the two wires: you'll need to trace the wiring and use a DMM or VOM to figure out which wire is "hot" and which is neutral or ground.


Canadian flag

120V / 240V A/C Electrical Wiring Color Codes & Conventions: Canada

Wire Insulation Color Alternative Wire Colors Label Function Comments
Black
Black wire
 
L
Line voltage, single phase Abbreviation: BK
Red
Red wire
 
L
Line voltage, single phase, second "hot" wire Abbreviation: RD
White
White wire
 
N
Neutral Abbreviation: WT
Black
Black wire
 
L1
Line voltage, 3-phase  
Red
Red wire
 
L2
Line voltage, 3-phase  
Blue
Blue wire
 
L3
Line voltage, 3-phase Abbreviation: BL
Green
Green wire
 
PG
 

Protective ground wire

Abbreviation: GN

Green + Yellow stripeGreen Yellow Wire
 
PG
 

Protective ground wire

Abbreviation: GN+YL

Bare
Bare copper wire
 
PG
  Protective ground wire

Notes:

1. 2012 Canadian Electrical Code (CEC) - see http://shop.csa.ca
Mississauga Office 5060 Spectrum Way, Suite 100 Mississauga, Ontario Canada, L4W 5N6 Toll-Free: (800) 463-6727 Tel: (416) 747-4000 Fax: (416) 747-2473
Edmonton Office 1707-94 Street North West Edmonton, Alberta Canada, T6N 1E6 Main: (780) 450-2111 Sales: (780) 490-2007 Fax: (780) 490-2059


Knob and tube wiring color codes (C) Daniel Friedman

This knob-and-tube electrical wiring photo has useful information for the electrician or building inspector.

First we can see that if we're in luck, the fabric portion of the wiring insulation may be intact and may clearly show that one conductor is white (neutral) and the other black (hot). With age the white insulation may have become tan or even brownish in color.

Second I'm a bit nervous about how that white wire is stripped back and is in contact with the hot black wire (arrow).

Finally, of course there is no protective ground on this circuit - we've got just two wires with which to contend.


U.K. FLag
120V / 240V A/C Electrical Wiring Color Codes & Conventions: U.K. United Kingdom

Wire Insulation Color Alternative or Older-Usage Wire Colours Label Function Comments
Brown
Brown wire
Red
Red wire
L
Line voltage, single phase Abbreviation: BN, RD
Blue
Blue wire
Black
Black wire
N
Neutral Abbreviation: BL, BK
Brown
Brown wire
Red
Red wire
L1
Line voltage, 3-phase Abbreviation: BN, RD
Black
Black wire
Yellow
Yellow wire
L2
Line voltage, 3-phase Abbreviation: BK, YL
Gray
Gray Wire
Blue
Blue wire
L3
Line voltage, 3-phase Abbreviation: GY, BL
Green + Yellow stripe
Green Yellow Wire
 
PE
 

Protective earth conductor

Abbreviation: GN+YL

Cream
Cream wire
 
PE
 

Functioning earth conductor

Abbreviation: IV (Ivory)

UK colur code amendments

Notes:

The U.K. currently follows the IEC AC wiring colour codes given
at I.E.C. I.E.E. ELECTRICAL WIRING COLOUR CODE CHART

New wiring colour codes replaced existing red & black phase & neutral conductors (left) with brown and blue (right) beginning in 2005. Where extensions or new work can result in mixed wiring colours, a warning must be fixed near the distribution board stating:
CAUTION: this installation has wiring colours to two versions of BS 7671. Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.
Regulating authority, IEC AC
I.E.E. Regulations (UK Standard BS 7671:2001) Requirements for Electrical Installations, IEE Wiring Regulations, Sixteenth Edition Amendment No. 2: AMD 14905, March 2004
"New Fixed Wiring Colours - A Practical Guide", www.nicelc.org.uk
"The IEE, ELectrician's Guide to the building regulations, including Approved Document P: Electrical Safety in Dwellings, Chapter 11"
Malta Resources Authority, "Harmonisation of Wiring Colour Codes, Practical Guidelines", http://mra.org.mt
www.i.e.e.org/cablecolours
Three phase wiring colour codes & color changes are shown just below:

UK 3 phase colour codes for wiring 3 phase


UK 3 phase colour codes for wiring 3 phase

This wiring shown above - well don't even think about figuring this out by color codes. Someone has just grabbed a piece of yellow wire and a blue wire, left an open splice, and jury-rigged something (not shown in our photo).

But when you see obviously amateur electrical--wiring like this it's a red flag to watch out, asking "what else did this fellow wire in this building?"


EU IEC Flag
120V / 240V A/C Electrical Wiring Color Codes & Conventions: Europe - IEC

Wire Insulation Color Alternative Wire Colors Label Function Comments
Brown
Brown wire
Black
Black wire
L
Line voltage, single phase Abbreviation: BN, BK
Blue
Blue wire
Blue
N
Neutral Abbreviation: BL
Brown
Brown wire
Black
Black wire
L1
Line voltage, 3-phase L1 is brown, black alternate
Black
Black wire
Brown
Brown wire
L2
Line voltage, 3-phase L2 is black, brown is an alternate
Gray
Gray Wire
Brown
Brown wire
Black
Black wire
L3
Line voltage, 3-phase

L3 is grey, brown and black are alternates

Abbreviation: GY, BN, BK

Green + Yellow stripe
Green Yellow Wire
 
PE
 

Protective Earth wire

Abbreviation: GN+YL

Notes:
Regulating authority, IEC AC



Table of Wire Color Code Abbreviations [1]

Color Abbreviation Code Wire Color Comments
AL Aluminum Aluminum colored wire (C) DF
ALL Any Color  
AM Amber Amber colored wire (C) DF
AO All Opaque  
AT All Transparent Transparent wire insulation (C) DF
BG Beige Beige wire color (C) DF
BK Black Black wire
BL Blue Blue wire
BN Brown Brown wire
BZ Bronze Bronze colored wire (C) DF
CH Charcoal Charcoal colored wire (C) DF
CL Clear Transparent wire insulation (C) DF
DK Dark  
GD Gold Gold colored wire (C) DF
GN Green Green wire
GY Gray Gray Wire
GT Granite  
IV Ivory (Cream in some countries) Ivory colored wire (C) DF
LT Light  
NC Natural (no pigmentation) Transparent wire insulation (C) DF
OL Olive Olive colored wire (C) DJF
OP Opaque  
OR Orange Orange wire
PK Pink Pink coloured wiring code (C) DJF
RD RED Red wire
SM Smoke (light gray) Smoke or light gray wire (C) DJF
TL Translucent Translucent wire insulation (C) DF
TN Tan Tan wire color (C) Daniel Friedman
TP Transparent (clear) Transparent wire insulation (C) DF
VT Violet Violet wire colour (C) Daniel Friedman
WT White White wire
YL Yellow Yellow wire
     
[1] In the U.S. UL (the Underwriter's Laboratory) has published wiring color acronyms and abbreviations. We have included the standard wiring color code abbreviations along witht the full color name in our tables of wire color standards in the article above. - retrieved 24 Feb 2014, original source: http://industries.ul.com/plastics-and-components/plastics/color-codes-and-abbreviations

 

 

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