1. Define the replacement boundary before comparing cables

Start with the equipment tags, complete drive model numbers, motor model and the intended operating duty. Record whether the project changes only the drive, or also the motor, feedback device, brake, output filter, enclosure position or machine motion. Obtain the applicable manuals and project drawings, including their revisions.

Create a separate cable ID for the incoming supply, drive-to-motor connection, brake circuit, encoder or resolver feedback, control wiring and communication link. A combined power-and-feedback assembly needs its own review against both equipment interfaces. Do not treat a common connector housing as evidence of identical pin assignments or signal requirements.

Industrial automation and control cabling

2. Build an evidence record for the installed cable

Trace both ends and the actual route. Record the cable marking, manufacturer and part number where available, conductor arrangement, installed length, intermediate joints, termination details and the corresponding drawing reference. Photograph identification and accessible terminations under the site work procedure. If a marking is unreadable, record the identification as unresolved rather than guessing a rating from diameter or jacket color.

Review visible damage, previous repairs, heat or chemical exposure and known movement history. An intact jacket is useful evidence of condition, but does not establish insulation performance or remaining flex life. Decide which checks are required with the responsible engineer. Electrical inspection and testing require the approved isolation procedure, verification of a safe state and the manufacturer’s instructions; connected drives and electronics must be protected from unsuitable test voltages.

3. Fill in the old-versus-new requirements matrix

Use one copy of the fillable comparison sheet per cable or identical, traceable cable group. Enter the old requirement, the new requirement and the actual evidence in different columns. Cite a document and page or an inspection record for each relevant entry. “Same as before” is not a substitute for the new equipment requirement.

Use the companion form to enter actual values and save the completed record. The prompts above identify the required information; they are not equipment specifications. A justified “not applicable” entry is preferable to an unexplained blank.

Open the fillable record template (save and print)

4. Resolve the differences that can change the decision

For power circuits, compare current-carrying requirements under the actual installation conditions, insulation ratings and termination limits. Equal motor power alone does not prove cable suitability. For the motor circuit, check the replacement drive’s permitted cable construction and length, together with any required output filter and motor-insulation conditions. Use the exact model documentation instead of a universal cable-length rule.

For feedback, brake and control circuits, compare the signal interface, conductor and pair arrangement, shielding, pin assignment and any manufacturer-approved assembly or adapter. A passive adapter changes the physical connection only; it does not establish protocol or electrical compatibility. Record approval for any changed assembly. Safety-related circuits require review within the machine’s applicable safety validation process.

Check the practical installation too: available conductor reach after retermination, connector clearance, cable-gland range, strain relief and the route at moving sections. Treat a new drag-chain or torsion duty as a changed requirement even when the route length stays the same.

Servo motor and encoder cable selection

5. Assign a disposition with a clear release condition

Assign a decision to each cable after reviewing all relevant rows. A conditional decision must name the missing action, its owner and the evidence required to close it. Do not allow a procurement status such as “material available” to replace engineering acceptance.

Illustrative decision logic: if a terminal accessory must change, keep the cable on hold until the new termination arrangement and available length are accepted. This is a workflow example, not approval for a particular cable or drive.

6. Convert approved actions into the retrofit materials list

For each approved change, list the cable or assembly specification, length basis, quantity, connector or terminal parts, glands, shield clamps and identification materials. Tie every line to a cable ID and the matrix decision. Separate mandatory replacement items from contingency spares so the buyer can see which materials are needed to release the work.

Close the record with the final drawing revision, installed configuration, inspection results and the responsible reviewer’s approval. Retain unresolved items separately if the work scope is reduced. A completed cable checklist supports the equipment change process; drive commissioning and machine-function checks still follow the approved project procedure.

Frequently asked questions