Wire Nut Color Chart: Sizes by Color, AWG Range and 3M Equivalents
Quick answer: There is no universal wire nut color code. Each manufacturer uses cap colors as its own sizing aid, so a tan or red wire nut from one brand does not fit the same wires as one from another. Use the color to find the size in that brand's line, then confirm your exact wire combination on the chart printed on the package. The one near-universal convention is green: a green wire nut, often with a hole in the tip, is for equipment grounding conductors only.
This guide gives the full color chart for Dicio winged wire nuts, explains how Dicio's two-color wire connectors line up with the 3M™ Performance Plus™ color codes many electricians already know, and walks through choosing a size by color without guessing. Crews buying by the box can go straight to the two-color collection or the 3,000-piece Red/Yellow box.
Is There a Standard Wire Nut Color Code?
No. The UL standard for splicing wire connectors, UL 486C, covers how a connector is tested and marked. It does not assign colors to sizes. The colors are a catalog convention that each manufacturer sets for its own line.
Why manufacturers color-code wire nuts
Color lets you grab the right size out of a mixed bucket or a truck bin without reading the package. Within one brand, the colors usually step up in size: small-wire caps for 22–14 AWG fixture leads, mid-size caps for 14 and 12 AWG branch circuits, and large caps for 10, 8 and 6 AWG.
Why colors do not carry across brands
Two brands can use the same color for different ranges, or the same range under different colors. Even when two connectors share a cap color, the listed wire combinations can differ. The package chart, not the color, tells you whether your splice is covered by the listing.
Green means ground
Green connectors are sold for equipment grounding conductors, and many have a hole in the tip so one ground can pass through as a pigtail. NEC 250.119 identifies equipment grounding conductors as bare, green, or green with yellow stripes, so a green connector fits that convention. Never use a green connector on a hot or neutral conductor. For the full install, see our green wire nut with hole guide.
Wire Nut Color Chart: Dicio Winged Connectors
The chart below shows every Dicio winged twist-on connector by cap color and overall wire range. Ranges come from Dicio product data. The range is the outer limit: only the combinations on the package chart are covered.
| Cap color | Dicio model | Wire range (copper) | Contractor box |
|---|---|---|---|
| Orange/Blue | ORBL | 22–12 AWG | 7,500 pcs |
| Tan/Red | TNRD | 22–10 AWG | 4,000 pcs |
| Red/Yellow | RDYW | 22–8 AWG | 3,000 pcs |
| Blue/Gray | BLGY | 14–6 AWG | 1,000 pcs |
| Tan | P12 | 22–8 AWG | 5,000 pcs |
| Yellow | P11 | 18–10 AWG | 5,000 pcs |
| Red (large) | P13 | 18–8 AWG | 5,000 pcs |
| Gray | P15 | 18–8 AWG | 2,500 pcs |
| Blue | P17 | 14–8 AWG | 1,500 pcs |
| Green with hole (ground) | P99 | 14–10 AWG | 5,000 pcs |
Retail packs of the two-color sizes are on the two-color collection page. Single-color yellow and tan come in smaller packs as winged twist-on wire connector nuts.
Two-Color Wire Nuts and 3M Performance Plus Color Codes
Dicio's four two-color winged connectors use the same two-tone cap colors as 3M Performance Plus: orange/blue, tan/red, red/yellow and blue/gray. If your crew already reads a T/R+ or R/Y+ cap by color, the Dicio cap in the same colors is the size they expect to reach for. The listed wire combinations are not identical, so check the Dicio chart before you swap one for the other.
| Cap color | Dicio model and range | Dicio max. combination | Dicio min. combination | 3M code and listed range |
|---|---|---|---|---|
| Orange/Blue | ORBL, 22–12 AWG | 3 × 12 AWG | 2 × 22 AWG | O/B+, 2 #22 to 3 #12 |
| Tan/Red | TNRD, 22–10 AWG | 3 × 10 AWG | 1 × 20 + 3 × 22 AWG | T/R+, 2 #18 to 5 #12 |
| Red/Yellow | RDYW, 22–8 AWG | 2 × 8 AWG | 1 × 20 + 3 × 22 AWG | R/Y+, 2 #18 to 2 #8 |
| Blue/Gray | BLGY, 14–6 AWG | 2 × 8 + 3 × 10 AWG | 1 × 10 + 1 × 14 AWG | B/G+, 4 #14 to 6 #10 |
The maximum and minimum are one listed combination each, not the whole chart. The full Dicio combination chart is printed on each package. 3M ranges are from 3M's product pages. 3M and Performance Plus are trademarks of 3M Company; Dicio is not affiliated with 3M.
Dicio two-color specifications
- Voltage: 600 V max.
- Temperature: 105°C
- Listing: UL Listed, file E113650
- Shell and spring: thermoplastic shell rated UL 94 V-2; zinc-plated square-wire spring
- Conductors: copper to copper only, solid and stranded; not for aluminum or copper-clad aluminum
Code and Standards Behind the Color
Color is a convenience. These are the requirements an inspector actually checks:
- NEC 110.14(B): conductors must be spliced with devices identified for the use. A wire nut listed as a splicing connector meets this when it is used within its listing.
- NEC 110.3(B): listed equipment must be installed according to its listing and instructions. For a wire nut, that means the combination chart, strip length and conductor material on the package.
- UL 486C: the product standard for splicing wire connectors. Look for the listing mark and the combination chart on the package. See our UL 486 standards guide for how to read a listing.
- NEC 250.119: equipment grounding conductors are bare, green, or green with yellow stripes, which is why green connectors are kept for grounds.
Section numbers follow the 2023 NEC. Check the edition your jurisdiction has adopted.
How to Pick a Wire Nut by Color
- Count and size the conductors. Note how many wires go into the splice and the gauge of each, including fixture leads. A splice of two 12 AWG and one 14 AWG is a different combination from three 12 AWG.
- Find a color whose range covers every wire. Use the chart above. The smallest and the largest conductor must both fall inside the range.
- Confirm the exact combination on the package chart. If your combination is not listed, step up or down a size and check again.
- Check the conductor material and location. Dicio winged connectors are copper to copper only and are for dry locations. For wet or buried splices, use a connector listed for it; see can wire nuts be used outside?
- Strip, twist and tug-test. Strip to the length on the package, hold the conductors even, and twist clockwise by the wings until the conductors start to twist below the skirt. Tug each wire. No bare copper should show below the skirt.
Common Wire Nut Color Mistakes
Assuming one brand's colors match another's
A red cap from one brand and a red cap from another can cover different ranges. Look up the size in the brand you are holding.
Reading the range as a promise for every pairing
"22–8 AWG" is the outer limit. A 22 AWG lead alone with an 8 AWG conductor may not be a listed combination. The chart decides.
Using a green connector on a hot or neutral
Green tells the next electrician the splice is a ground. Putting it on a current-carrying conductor breaks that convention and can mislead whoever opens the box next.
Splicing aluminum with copper-only connectors
Dicio winged connectors are for copper only. Aluminum branch circuits need connectors listed for aluminum; see our aluminum wire connector guide.
Using a dry-location wire nut outdoors
Standard winged wire nuts are not sealed. Splices in damp, wet or direct-burial locations need a connector listed for that use.
Wire Nuts by Color vs Other Splicing Methods
| Color-coded wire nuts | Lever connectors | Push-in connectors | |
|---|---|---|---|
| How you pick the size | Cap color, then package chart | Port count and wire range | Port count and wire range |
| Wire combinations | Many mixed-gauge combinations per size | One wire per port | One wire per port |
| Stranded wire | Yes, within the chart | Yes | Often solid only; check the package |
| Reusable | Can be removed and reinstalled | Yes, open the lever | Usually not designed for reuse |
| Cost per splice by the box | Lowest | Higher | Higher |
For a deeper comparison, see lever connectors vs wire nuts and wire nuts vs push-in connectors.
Frequently Asked Questions
Are wire nut colors universal?
No. Each manufacturer sets its own colors. The only widely shared convention is green for equipment grounding conductors. Always check the package chart of the brand you are using.
What color wire nut do I use for 12 gauge wire?
12 AWG falls inside the range of every Dicio winged size, so the choice depends on how many wires and what other gauges share the splice. For a splice of 12 AWG conductors only, Orange/Blue lists three 12 AWG as its maximum. Larger or mixed splices need the size whose package chart lists that exact combination.
What color wire nut do I use for 10 gauge wire?
10 AWG falls inside every Dicio winged range except Orange/Blue (22–12 AWG). Tan/Red lists three 10 AWG conductors as its maximum, and Blue/Gray takes 10 AWG together with 8 AWG. Check your exact combination on the package chart.
What does a tan/red wire nut fit?
The Dicio Tan/Red (TNRD) connector is listed for 22–10 AWG copper, from one 20 AWG plus three 22 AWG up to three 10 AWG. Other brands' tan/red caps can cover different ranges.
Can I use a 3M Performance Plus chart to choose Dicio connectors?
Use it only to recognize the color. The Dicio connectors share the 3M cap colors but have their own listed combinations, shown on the Dicio package.
What is a green wire nut with a hole for?
It splices equipment grounding conductors and lets one ground pass through the tip as a pigtail to the device or the box ground screw. It is not for hot or neutral conductors.
Are Dicio wire nuts rated for 600 volts?
The Dicio two-color winged connectors are rated 600 V max. and 105°C. For other models, check the product page and package.
Buying Color-Coded Wire Nuts by the Box
Standardizing a crew on one color system cuts sorting time and wrong-size callbacks. Dicio sells every size in this chart in contractor boxes, and the two-color line in retail pouches as well:
- Two-color wire connectors: Orange/Blue, Tan/Red, Red/Yellow and Blue/Gray, in pouches and in boxes of 1,000 to 7,500.
- Tan P12 and Yellow P11 single-color winged connectors, 5,000 per box.
- P99 green ground connectors, 5,000 per box.
Electrical contractors and distributors can request free samples and volume pricing through Dicio PRO for electricians, or contact the Dicio team for spec sheets and stocking programs. Ordering for a full crew? See our guide to buying wire connectors in bulk.
This guide is general information. Follow the code edition adopted in your area, your authority having jurisdiction, and the instructions and combination chart on each package.
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