Robot Cable Color Code and Wire Marking: What to Specify Instead of Assuming

Do not assume a core color means the same thing across suppliers. Wiring color rules vary by locality, country or region, the most-used multi-core color table was withdrawn as a standard in 1998, and a conductor-size marking can be read two ways. The reliable approach is to write the core-to-pin table and the size notation on the drawing, then verify the finished cable against that table.

This guide covers what the public references say about core colors and size marking, how to read AWG and stranded designations, a worked size example, and what to put in the RFQ. For the commercial side of custom colors, see our custom wire color RFQ guide; for labeling and kitting, see the kitting and labeling guide.

Which code applies to which job

Color and marking answer three different questions, and each has its own reference.

The first row is a safety identification, so treat it as fixed. The second is a convention, not a guarantee: a cable made to a different table can still be a good cable, but only if the drawing says which table it follows.

Core colors: what DIN 47100 actually defines

DIN 47100 specifies 60 color combinations for cable cores. Cores 1 to 10 are single colors in this order: white, brown, green, yellow, grey, pink, blue, red, black, violet. Cores 11 to 44 use two-color combinations, and cores 45 to 60 use three colors, which the reference describes as rare. In a cable, the insulation of each wire is either solid in one color or striped lengthwise in two.

Two limits matter in practice. The standard was written for telecom cables, and it no longer has a current revision, so a robot cable maker may follow it, follow its own table, or follow a customer table. Do not read a color from a photo or a sample and assume the same table. Ask for the cable datasheet's core table, or define the table yourself on the drawing.

Size marking: AWG, strands and square millimetres

AWG is a logarithmic scale, which makes it easy to check a number against a rule of thumb. From the AWG reference: when the diameter of a solid round wire is doubled the AWG decreases by 6; when the cross-sectional area is doubled it decreases by 3; and a decrease of ten gauge numbers, for example 24 AWG to 14 AWG, multiplies the area by approximately 10. The reference gives the diameter of 36 AWG as 0.127 mm and the formula for any gauge n as 0.127 mm x 92^((36-n)/39) (Wikipedia: American wire gauge).

Worked example (solid conductor, computed from the formula above).

Check it with the rule: 18 AWG to 24 AWG is six steps, so the diameter should roughly halve (1.024 to 0.511). It does.

These are values for a solid conductor. A stranded conductor is built differently, so take its overall diameter from the cable datasheet and use that number for fit and routing decisions.

Reading a stranded designation. The AWG reference writes it as three numbers: overall AWG size, strand count, and the AWG of each strand, separated by a slash. For example, a 22 AWG 7/30 stranded wire is a 22 AWG wire made from seven strands of 30 AWG wire. For a cable that must flex, the strand construction matters as much as the size, so the strand count belongs on the drawing next to the AWG size.

Metric sizes do not map to AWG exactly. If your design is in square millimetres and the supplier quotes in AWG, put both on the drawing and say which governs; a 0.5 mm2 conductor and the nearest AWG size are not automatically interchangeable.

What to write on the drawing

The goal is that two suppliers reading the same drawing build the same cable. Put these items on it:

• A core-to-pin table. Connector A pin, connector B pin, core number, color or color pair, and conductor size. The pin map is the requirement; the color is the aid.
• The table you follow. Name it: DIN 47100 as a convention, the cable maker's datasheet table, or your own table. Never leave it implied.
• Protective earth. Mark which conductor is protective earth and state green/yellow where your market and machine standard require it.
• Size notation. AWG, strand count and square millimetres, with the governing one stated.
• Marking on the assembly. What is printed or labeled on the cable and where, and the revision of the drawing it was built to. See the kitting and labeling page for how that carries through to the line.

If you want a second pair of eyes before release, a drawing review is the right place to catch a missing table or an ambiguous size note.

Verify the cable, not the colors

Color is easy to get wrong in a way that still looks right: two similar colors swapped at one end, or a striped core mistaken for a solid one. The check that does not depend on eyesight is continuity from connector pin to connector pin against the pin map, recorded in the test report. Where insulation matters, add the insulation tests your specification calls for; the wire harness testing page explains how those are defined. A cable that passes the pin map is correct whatever the colors look like, and a cable that fails it is wrong even if the colors match.

Three views on the same decision

• Engineering: wants the table on the drawing and a pin-map test, so a color mismatch becomes a documented finding instead of a field surprise.
• Purchasing: wants one table all suppliers quote against, so the quotes compare like for like and a substitution is visible.
• Quality: wants the pin-map report and the drawing revision recorded, so a returned cable can be traced to the table it was built to.

What to send with the RFQ

Send the drawing with the core-to-pin table, the table you follow, the conductor sizes in AWG and square millimetres, the strand requirement for flexing sections, the protective-earth marking, the label content, and the test record you expect. Pair it with the robot arm or collaborative robot routing information if the cable moves with the arm.

FAQ

Is there one color code that all robot cables use?

No. Wiring color rules vary by locality, country or region, and the IEC works to harmonize them rather than having made them uniform. For multi-core signal and control cables the widely used table is DIN 47100, which was withdrawn without replacement in 1998 yet remains in widespread use by cable manufacturers. Because of that, write the core-to-pin table on your drawing instead of relying on color alone.

What color is the protective earth conductor?

Green and yellow. Most jurisdictions now require the protective earth conductor to be insulated to the same standard as the current-carrying conductors with green/yellow insulation. Check the requirement of the market and the machine standard you build to.

How do I read a stranded wire designation like 22 AWG 7/30?

It is a 22 AWG conductor made from seven strands of 30 AWG wire: the overall AWG size, then the strand count, then the AWG of each strand, separated by a slash.

Can I use AWG sizes on a drawing for a metric cable?

You can, but state both the AWG size and the cross-section in square millimetres, and say which one governs. The two scales do not match exactly, so a metric size such as 0.5 mm2 and the nearest AWG size are not interchangeable without a check against the cable datasheet.

How do I make sure the colors on the finished cable match the drawing?

Test the finished assembly against the pin map, not against the colors. A continuity test from connector pin to connector pin catches a swapped core even when both colors look plausible, and the test report records that the map was met.

Have a robot cable drawing that needs a core table and a clear size note? Send it through our contact page and we will review it with you before the first build.