Q&A about electrical wiring colour codes:

This article series 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.

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

These questions and answers about the use of colour codes to identify electrical wires and their functions were posted originally at ELECTRICAL WIRING COLOR CODES - be sure to see the tables of color codes given there.

Question: are there accepted conventions to the abbreviations of electrical wiring color codes?

(Mar 12, 2014) Keith E. Davis said:

Tell me is there an excepted convention as to the abbreviations of electrical wiring color codes?

Reply:

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. Thanks for asking.

Also see UL Standard 83 - Thermoplastic-Insulated Wires and Cables

Question: ok to reverse red and black wires?

(July 18, 2014) Eric said:
Does it matter if the red wire and black be reversed?

Reply:

Eric without knowing what's being wired all we can say is ... Yes it might.

Generally in house wiring the red wire is a second 120V circuit on a different "phase" such that it can either provide 120V to a device or if wired along with the black wire to two terminals on some devices (such as a 240V motor) the circuit will be provided with 240V. In a 240V circuit generally which terminal gets the red and which the black won't matter.

Question: wiring an electric 600V water heater in Canada

(Sept 11, 2014) Bob said:

For Canada, 600V unit, water heater, does the ground wire have to be green/yellow or just green?

I'm referring to internal wiring, sorry.

Reply:

Bob Here's a quick summary of colour conventions for the protective ground wire:

The protective ground wire (listed as green-yellow in CURRENT codes & standards) is green with yellow stripe in the UK and IEC.

In the U.S. the ground wire might be bare, or green-yellow (preferred) or green (alternative)

In Canada the ground wire (Protective Ground or labelled PG) can be green-yellow OR green.

On 2018-01-17 by (mod) - Selecting a proper color wire is important for security.

re-posting

Odelia Murch said:
Wire with different color indicates electrical parameters like tolerance, reliability, power and more. Selecting a proper color wire is important for security. According to its application, electricians in Conshohocken PA Florida, Alaska can guide us in selection of wire.

On 2017-10-09 by (mod) - Green and green/yellow are usually ground.

Green and green/yellow are usually ground. Check that before hooking up the motor by looking for continuity between those wires and the motor's metal casing and base.

On 2017-10-08 by Anonymous

I purchased a chinese engine lathe 230 volt and the cord have 4 wires (brown, blue, green and green/yellow) i want connect a 230 volt plug.From the panel box, is outlet on the wall with (red,black white and bare) how to hook up these wires?

On 2017-03-20 by (mod) - use a VOM or DMM to check wires

Getto

In discussing building electrical wiring, You'd normally use a VOM or DMM to check wires to be sure you know which ones are hot, ground, neutral; If your electrical system is 120VAC or 240VAC your electrical wires are not "positive" or "negative" but if your wiring is DC then yes the meter will show you which is which.

Usually green is ground and a red wire would usually be hot.

On 2017-03-20 by Getto cruiser

W i h as ve a green an red wire on my c b system is it pos or neg

On 2017-03-15 by (mod) - What is the switch wire color for the IEC hot?

At the beginning of the article ELECTRICAL WIRING COLOR CODES check this live link I.E.C. I.E.E. ELECTRICAL WIRING COLOUR CODE CHART

On 2017-03-15 by Phill Cam

What is the switch wire color for the IEC hot?

On 2016-12-28 by (mod) - What wires are hot and which are neutral?

Anon:

In the colour charts at ELECTRICAL WIRING COLOR CODES, "Line" or "line voltage" are synonyms for "hot" - often black or red.
and
"Neutral" wires are so identified in the colour charts. Usually white.

On 2016-12-28 by Anonymous

What wires are hot and which are neutral?

On 2016-12-09 0 by (mod) - electric wire color code history

CLV

Thank you for the interesting color code and bit of history. Indeed, natural gray wires on color code charts look dull-white.

I looked for an authoritative electrical wire colour code reference that included the definition of Natural Gray wire and didn't find one. If you can help us out please do.

Daniel

On 2016-12-08 by clv

"Natural gray" as used in the code is not gray, it's the color of undyed cotton and is mostly a historic curiosity.

On 2016-09-17 by (mod) - red and black but my heater has pink and green

Most likely, yes. If you have two live 20A wires running from the circuit breaker to an electric water heater, you should find two 120VAC wires (together they're giving you 240V) in the water heater.

Take a look at our electric water heater element replacement and electrical wiring examples found

at ELECTRIC WATER HEATER ELEMENT REPLACEMENT
and
given the brand and model of your own water heater, if you don't already have an installation and operation manual showing wiring, one is certainly available from the manufacturer.

by the way: a two-wire 240V circuit to a water heater should be powered by a single double-pole common-trip circuit breaker, NOT two physically independent circuit breakers; that would be unsafe.

On 2016-09-17 by Gene

Additional info: I just opened my fuse panel and have identified both the red and the pink wires. They are each running to 20A breakers. So does this mean that they are both hot? if so, does it matter then which wire goes to which? I only have two choices here: red to red / pink to black OR red to black / pink to red. Help.

I'm putting in a new hot water heater in a 60yr old building. I didn't pay attention when I took out the old unit and am now confused by the wiring. The new unit has simply a red & black, but my line has red, pink and green. I know the green is the ground, but don't know which goes to which of the others and am afraid I'll ruin the water heater if I wire it incorrectly. Help.

On 2016-05-09 by (mod) - blue and white they were both hot even when i turned off all the circuits

Anon:

What you describe sounds dangerous. If you switch off the MAIN PANEL MAIN BREAKER or fuse for the whole church, all circuits should be OFF.

But if you were just switching off some breakers and missed a sub panel somewhere, that might explain why some wires were still hot.

Start where the electrical service comes into the building. Follow the wires - be sure you've found the main breaker or fuse for the building or in some cases there may be up to 6 main switches. (More than that is not recommended and is unsafe).

There might be a circuit powered off of a usually-on circuit that is intended to power fire or smoke alarms. Those are not normally switchable.

On 2016-05-09 by Anonymous

I was working at our church and came across blue and white they were both hot even when i turned off all the circuits,what might they be for.

On 2016-01-11 by Anonymous

One wire has a red green and black one has brown green an Ted hoe do I match them by

...

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