Insulation color code for wire inside conduit (residential)

[theoldwizard1]

A couple of question all related to residential branch circuits where the conductors are inside of a conduit ?

Does ground have to be green insulation ? Can it be bare ? Can it be black win a green mark (tape) ?

Does neutral always have to be white ? Black with a white mark (tape) ?

When running 240V, when can you use black for both L1 and L2 ?

I know typically you would use black and red for L1 and L2. If you are running a second circuit in the same conduit what are the recommended colors for those wires ?

 

[Bad Habit]

For the ground, bare, green, or green with yellow stripes. If the grounding conductor is #4 or larger, it is permitted to be permanently marked with green tape, or some other acceptable manner at each termination, splice and at every point the conductor is accessible.

Neutral #6 and smaller needs to be white or gray (or have a 3 continuous white stripes). #4 and larger can have white tape or other acceptable marking at terminations, splices, etc..

L1, L2, (L3) can be any color other than white, gray, or green. Typical 120/240 1ph is Black, Red - 120/208 3ph Black, Red, Blue - 277/480 Brown Orange, Yellow. Then some other color for switch legs

 

[u2slow]

In North America... generally white, white stripe, or grey are reserved for neutral, and green/bare for ground. Line conductors may be other colours. This is by regulation and practise - physics does not care.

Bare wire is often not allowed in conduit.

No mandatory special colours for different voltages in Canada.

 

[Terry D]

There are no different rules for conductor colors whether it is for residential, commercial or industrial. Hots can be any color except white, grey, green or green with yellow stripe. As already mentioned, cannot re identify colors with tape on conductors smaller than #4 . No bare for the ground in pipe.

Although it is common practice for color combinations for 3-phase voltages, it is not required by the NEC

 

[ROBZ71LM7]

I just ran multiple 120V circuits in the same 3/4" EMT in my attached garage. I used Black and White on One and Red and Gray on the other-makes it super easy to tell circuits apart. On another run of EMT with multiple 240V circuits, one was all black and one all red. In situations where I needed a third circuit I used THHN from a different manufacturer (Southwire versus Cerro). I ran green THHN in conduit for my ground obviously.

 

[Solarphil]

Where in the NEC is the part about bare copper grounds not being allowed in conduit? I’m genuinely curious

 

[Terry D]

Where in the NEC is the part about bare copper grounds not being allowed in conduit? I’m genuinely curious

Its not that a bare ground is not allowed in conduit. When I do a service, I always put my #6 bare copper from the meter socket to the ground rod in PVC conduit. If you were to use a metallic conduit, you would have to bond that bare copper to both ends. I believe the OP was asking about a conduit run filled with branch circuit conductors, if the EGC could be bare. I guess it could, but why. I personally have never seen it done. Maybe it is more common in solar applications.

 

[Solarphil]

No worries, I’m sort of geeky that way - when I saw two folks mention a possible limit on bare EGCs in conduit I wanted to ask. I figured since u2slow is from Canada I know they have a slightly different standard so I didn’t worry too much about it, but when you said a similar thing I wanted to check, in case there was something I missed. Like you said, I’ve sometimes found what one person says is an absolute requirement often turns out to simply be a matter of preference. I can understand that, I just like to keep it clear.

You were spot on with your answer re color coding and re-marking. There are color *conventions* - like split phase black/red and three phase 120/208 vs 277/480, but those are simply that: conventions, not requirements. But yeah, technically other than grey or white, and green or green with a yellow stripe, the hot conductors can be any color under the rainbow. In some industrial complexes, the wire colors in a box can look like a bowl of skittles. When I build my garage I’ll likely do the same - I like to be able to clearly identify any circuit, at any junction point. It’s pretty darned handy, and color is free.

 

[Dagny]

never saw bare 12 gauge for sale.

 

[Dagny]

They make white thhn with a red or blue tracer.

 

[dscheidt]

A couple of question all related to residential branch circuits where the conductors are inside of a conduit ?

In Chicago, where everything is conduit, what you will find in single and two or three flats where the work was done by someone with a license, is that hots are black and red, in strict alteration. Neutrals are all white, with gray very rarely showing up. I have once seen white with a dashed red stripe. Ground is the conduit, almost exclusively, but a green shows up in outside work on occasion.

Colors are used for switch legs, travelers for n-way circuits, and stuff like. Brown, blue, yellow are the first ones (not always in that order, there's some variation). After that, it's whatever-is-handy.

Also, expect lots and lots of multi-wire branch circuits, because it's three wires for two circuits instead of four, and only two of them are current carrying. Both are important for conduit capacity.

If the work was done by a homeowner, handyman, or someone else, all bets are off.

 

[Bert_]

I'll label phases on the service. At least for 3 phase, labeling red and black on single phase is a waste.

When pulling circuits in conduit I pretty much never use a specific color for a phase. Doesn't really gain you anything.

 

[Terry D]

never saw bare 12 gauge for sale.

Me either, till I googled it, it does exist

12 AWG Soft Drawn, Stranded, Bare Copper Wire

12 AWG Soft Drawn Stranded Bare Copper. Cut by the foot

www.wireandcableyourway.com

 

[BreeStephany]

120/208 - 120/240 1ph & 3ph Wye & Delta Colors

• Green, phased green with electrical tape or bare for ground
• Green with yellow bands for isolated ground
• White or phased white with electrical tape for 120/240 or 120/208 system neutrals
• Black & red for 120/240 1ph line colors
• Black, red & blue for 120/208 3ph wye line colors
• Black, orange, blue for 120/240 3ph delta line colors with the high leg (~190+ V to ground / neutral) phased orange

277/480 3ph Colors

• Green, phased green with electrical tape or bare for ground
• Green with yellow bands for isolated ground
• Grey or phased grey with electrical tape for 277/480 system neutrals
• Brown, orange yellow (BOY) for 277/480 3ph line colors

Here's a great chart for international phasing colors
This may be beneficial if you are ever buying 60hz equipment from other countries and trying to figuring out the phasing.


Now, in regard to the questions you posted above,

Does ground have to be green insulation ? Can it be bare ? Can it be black win a green mark (tape) ?

• The grounding conductor coming from earth (i.e. ground rods, metal water or fire sprinkler riser, structural steel, etc.) is bare, however, once you start running your conductors in conduit past your main disconnect, you are likely going to want to start using stranded conductors for ease of pulling, for vibration resistance, etc., in which case, you are going to use a green conductor, sized appropriately, as per NEC 250.122 to the circuit you are pulling to or the largest circuit in the conduit.

Does neutral always have to be white ? Black with a white mark (tape) ?

• For ease, if your conductors are smaller than #4, you should use colored conductors. With that said, it is acceptable to phase a black conductor with white tape wherever it is visible (i.e. panels, pull boxes, etc.) so that it can be easily identified in the future, especially if anyone has to do any troubleshooting in the future.

When running 240V, when can you use black for both L1 and L2 ?

• Using 2 black wires for both L1 and L2 in a 240V 1ph system is acceptable, however, I would again suggest that you phase L2 as red from the main disconnect throughout your system, again so that they can be easily identified in the future and also during installation.

I know typically you would use black and red for L1 and L2. If you are running a second circuit in the same conduit what are the recommended colors for those wires

• Run the same colors, however, use wire markers, like Ideal's number books to identify the circuit number in the end points of the conductor / points of termination, again, so that they can be easily identified in the future and during installation. When pulling the circuits through the conduit at the point of origination, tape your corresponding circuits together and mark them with wire numbers so that you can easily identify them on the other end of the conduit. Also, keep the phase colors the same from every point from the main disconnect throughout the system. This makes sure you don't accidentally mix phases and create dead shorts in your system.

Just my two cents!

 

[Norcal]

120/208 - 120/240 1ph & 3ph Wye & Delta Colors

• Green, phased green with electrical tape or bare for ground
• Green with yellow bands for isolated ground
• White or phased white with electrical tape for 120/240 or 120/208 system neutrals
• Black & red for 120/240 1ph line colors
• Black, red & blue for 120/208 3ph wye line colors
• Black, orange, blue for 120/240 3ph delta line colors with the high leg (~190+ V to ground / neutral) phased orange

277/480 3ph Colors

• Green, phased green with electrical tape or bare for ground
• Green with yellow bands for isolated ground
• Grey or phased grey with electrical tape for 277/480 system neutrals
• Brown, orange yellow (BOY) for 277/480 3ph line colors

Here's a great chart for international phasing colors
This may be beneficial if you are ever buying 60hz equipment from other countries and trying to figuring out the phasing.


Now, in regard to the questions you posted above,

Does ground have to be green insulation ? Can it be bare ? Can it be black win a green mark (tape) ?

• The grounding conductor coming from earth (i.e. ground rods, metal water or fire sprinkler riser, structural steel, etc.) is bare, however, once you start running your conductors in conduit past your main disconnect, you are likely going to want to start using stranded conductors for ease of pulling, for vibration resistance, etc., in which case, you are going to use a green conductor, sized appropriately, as per NEC 250.122 to the circuit you are pulling to or the largest circuit in the conduit.

Does neutral always have to be white ? Black with a white mark (tape) ?

• For ease, if your conductors are smaller than #4, you should use colored conductors. With that said, it is acceptable to phase a black conductor with white tape wherever it is visible (i.e. panels, pull boxes, etc.) so that it can be easily identified in the future, especially if anyone has to do any troubleshooting in the future.

When running 240V, when can you use black for both L1 and L2 ?

• Using 2 black wires for both L1 and L2 in a 240V 1ph system is acceptable, however, I would again suggest that you phase L2 as red from the main disconnect throughout your system, again so that they can be easily identified in the future and also during installation.

I know typically you would use black and red for L1 and L2. If you are running a second circuit in the same conduit what are the recommended colors for those wires

• Run the same colors, however, use wire markers, like Ideal's number books to identify the circuit number in the end points of the conductor / points of termination, again, so that they can be easily identified in the future and during installation. When pulling the circuits through the conduit at the point of origination, tape your corresponding circuits together and mark them with wire numbers so that you can easily identify them on the other end of the conduit. Also, keep the phase colors the same from every point from the main disconnect throughout the system. This makes sure you don't accidentally mix phases and create dead shorts in your system.

Just my two cents!

If smaller then 4 AWG, you MUST, not "should", use conductors with the conductor insulation colored green or white, phase tape is not acceptable nor code compliant.

 

[Terry D]

Leave it to China to use green as a phase conductor. And Japan uses white for a neutral and a phase conductor

 

[sparky 1971]

If smaller then 4 AWG, you MUST, not "should", use conductors with the conductor insulation colored green or white, phase tape is not acceptable nor code compliant.

They let us get by with taping #8 and #6. I don't very often, but have done it. The actual electrical inspectors know it's a pain in the *** for a service guy to carry all those spools on a truck and the inspect it all inspectors have no clue about what can and can't be marked.

If I am working somewhere and there is not 480 in the building, I am using all the colors available to me on the 120/240/208. If there is 480/277, I'm using the "standard" colors.

 

[Bert_]

Leave it to China to use green as a phase conductor. And Japan uses white for a neutral and a phase conductor

In one of the school buildings I do work in there is a wing with lots of green switch legs.

 

[Terry D]

In one of the school buildings I do work in there is a wing with lots of green switch legs.

I saw that alot when i worked for the City of St. Louis. I think they used what ever they had on the truck at the time.

 

[u2slow]

How old is this NEC size/colour rule?

What about multi-conductor cable without the colour(s) you need?

 

[Terry D]

How old is this NEC size/colour rule?

What about multi-conductor cable without the colour(s) you need?

That has been around for at least 25 years, probably longer. As far as using the white in a NM-b or MC cable for a hot, You are allowed to reidenify it. It can only be used for the supply to the switch, not as the return conductor from the switch to the outlet. One example being a 3-way circuit or a switch leg. I have at times, when using a 2-conductor cable for 240 volt loads, had the inspector tell me put a piece of black tape on the white at the breaker. I have just got into a habit to do it all the time

 

[EricS]

120/208 - 120/240 1ph & 3ph Wye & Delta Colors

• Green, phased green with electrical tape or bare for ground
• Green with yellow bands for isolated ground
• White or phased white with electrical tape for 120/240 or 120/208 system neutrals
• Black & red for 120/240 1ph line colors
• Black, red & blue for 120/208 3ph wye line colors
• Black, orange, blue for 120/240 3ph delta line colors with the high leg (~190+ V to ground / neutral) phased orange

277/480 3ph Colors

• Green, phased green with electrical tape or bare for ground
• Green with yellow bands for isolated ground
• Grey or phased grey with electrical tape for 277/480 system neutrals
• Brown, orange yellow (BOY) for 277/480 3ph line colors

Here's a great chart for international phasing colors
This may be beneficial if you are ever buying 60hz equipment from other countries and trying to figuring out the phasing.

Slight correction for the Canada listing, for 3 phase L1= Red, L2= Black L3= Blue and not voltage dependent. For single phase black and red = hot. The colours for neutral and ground the same.

Also in place of 277/480 the standard up here is 347/600.That being said it's common to come across 480 motors for industrial equipment