# MTW vs TC-ER Cable: What's the Difference and When Do You Need Both?

> Compare MTW and TC-ER cables, UL 1063 vs UL 1277, exposed-run requirements, and dual-rated cable options for industrial machinery.

- Canonical page: https://devcable.com/blog/mtw-vs-tc-er-cable/
- Language: en
- Published: 2026-10-21
- Category: Technical Guide
- Topics: MTW vs TC-ER cable, UL 1063, UL 1277, industrial machinery

A European machinery manufacturer is preparing equipment for North America. Its cable schedule says “MTW TC-ER cable,” but the supplier offers a tray cable with a different insulation system. Are these descriptions interchangeable?

**MTW means Machine Tool Wire, covered by UL 1063; TC-ER means Tray Cable — Exposed Run, covered by UL 1277.** They address different construction and application requirements. Some products carry both designations, but neither proves the other. You need both when the project requires a single cable to satisfy both sets of requirements, supported by its actual marking and certification.

## MTW vs TC-ER Cable at a Glance

Use this comparison to screen a specification. Specific characteristics depend on the actual construction and documented ratings.

| Selection point | MTW | TC-ER |
|---|---|---|
| Full designation | Machine Tool Wire | Tray Cable — Exposed Run |
| Relevant UL standard | UL 1063 | UL 1277 |
| Primary application | Industrial machinery wiring | Power/control tray wiring and permitted exposed runs |
| Typical construction | Thermoplastic-insulated wire; specified multi-conductor constructions also covered | Insulated circuit conductors under an overall jacket; materials vary |
| Installation context | Machinery requirements, including NFPA 79 where applicable | NEC Article 336 and other applicable installation provisions |
| Key markings | MTW and applicable electrical/environmental ratings | TC-ER and applicable electrical/environmental ratings |
| Industry usage | Machine tools, OEM equipment and machinery panels | Plant power/control routes and equipment connections |
| Purchasing focus | Machine wiring duty, construction, terminations | Route, support, protection and equipment entry |

## What Is MTW Cable?

Type MTW is associated with wiring industrial machinery, including machine tools. The official [UL 1063 scope](https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=44807) covers all-thermoplastic machine-tool wires and cables. It describes PVC-insulated single-conductor constructions, with a nylon covering in one construction, and specified multi-conductor assemblies enclosed in a PVC jacket. MTW is therefore not limited to loose single wires.

[NFPA 79](https://www.nfpa.org/codes-and-standards/nfpa-79-standard-development/79), the Electrical Standard for Industrial Machinery, supplies machinery context; it is not a substitute for product certification. Select MTW cable for machine tools by reviewing circuit voltage, conductor temperature, wet or dry conditions, oil/coolant exposure, conductor identification and terminal compatibility. Ratings associated with another designation on the same cable may differ.

Flexible stranded conductors can ease routing, but do not establish continuous-flex or drag-chain suitability. Specify movement separately. Likewise, MTW alone does not establish permission for a cable-tray route or an exposed installation outside the machine.

## What Is TC-ER Cable?

TC means Tray Cable. [UL 1277](https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=34913) covers electrical power and control tray cables, including constructions with optional optical-fiber members. TC-ER adds an exposed-run designation relevant to permitted connections between a cable tray and utilization equipment.

For a proposed exposed run, review mechanical support, protection against physical damage and equipment entry under the adopted NEC and project requirements. The standard's scope describes continuous support and mechanical protection such as struts, angles or channel. Specific installation permissions and exceptions must be checked in the applicable code edition. TC-ER is not unconditional permission to eliminate conduit everywhere.

DEV CABLE's [XLPE/PVC TC-ER tray cable construction](/products/tc-er-cable/) uses stranded copper conductors, XLPE insulation and a PVC outer jacket, with a UL 1277 construction-specification reference. This does **not** establish UL Listing, UL 1063 Type MTW status or dual certification for that product. XLPE insulation must not be presented as the thermoplastic MTW construction described above.

## UL 1063 vs UL 1277: Key Differences

Product standards address cable construction and evaluation. Installation codes govern how the selected wiring method may be used. A listing or certification identifies an evaluated product within a defined scope; citing a standard is a different statement.

| Standards question | UL 1063 | UL 1277 |
|---|---|---|
| Scope | Machine-tool wires and cables | Electrical power and control tray cables |
| Construction | Defined all-thermoplastic MTW constructions | Jacketed tray-cable constructions with specified conductor systems |
| Application focus | Wiring associated with industrial machinery | Tray and other permitted power/control wiring methods |
| Evidence to check | MTW designation and model-specific certification | TC designation, ER marking where required, and model-specific certification |

Two black, stranded, multi-core cables can look similar while having different insulation, ratings and approvals. Neither appearance nor a supplier's “equivalent” description resolves UL 1063 vs UL 1277 applicability. A construction drawing helps compare materials and dimensions, but it cannot replace the relevant certification record.

## Can One Cable Be Rated Both MTW and TC-ER?

**Yes. Certain industrial cables can carry both designations when the particular construction has been evaluated and certified appropriately.** For example, LAPP's [ÖLFLEX CONTROL TM model information](https://vn.lapp.com/en/products/281004) identifies MTW under UL 1063 and TC-ER under UL 1277. This illustrates the possibility; it does not transfer those approvals to another manufacturer's cable or every size in a family.

Combining the designations can help an OEM specify one approved construction across machinery and tray-routing duties. It can reduce purchasing variants when both applications genuinely need that construction. It does not remove the installation requirements at either end.

Before accepting a claimed dual-rated MTW TC-ER cable:

1. **Obtain the exact datasheet.** Match manufacturer, model, revision, conductor size, core count and construction to the quotation.
2. **Check the full marking legend.** Request a legible jacket-marking example and the reel or package certification label, rather than an isolated logo photograph.
3. **Confirm certification records.** For a UL claim, check the relevant records through Product iQ and reconcile the manufacturer, file/category and covered product.
4. **Confirm both standards apply.** Establish UL 1063 and UL 1277 coverage for the ordered variant, including exclusions. Two standard numbers in marketing material are insufficient.
5. **Review the installation.** Map internal machine wiring, tray routing and the exposed transition; check the applicable requirements for each segment.
6. **Verify operating ratings.** Check voltage, temperature under each designation, wet/dry use, oil, sunlight, chemicals, bending and movement.

Keep three procurement statements separate:

- **Technical equivalence:** an engineering comparison for a defined duty. Similar dimensions or materials do not establish identical approvals.
- **Construction-specification compliance:** a claim that a product meets specified construction requirements. Ask what evidence supports the claimed scope.
- **Certified/listed product:** an identified product evaluated within a third-party certification program, with applicable marking and records.

UL's [Wire and Cable Application Guide](https://www.ul.com/thecodeauthority/knowledge/wire-cable-guide) explains multiple type designations and certification identification. Jacket printing is supplemental; include the reel or package label and certification information in the review.

## Which Cable Should You Specify?

### Scenario A: Internal Machine-Tool Wiring

Start with the machinery wiring specification and NFPA 79 where applicable. Review conductor size, terminal acceptance, identification, routing, protection, voltage and temperature. If MTW is required, obtain evidence for the proposed wire or cable. A TC-ER designation alone does not answer the machinery requirement; adding tray suitability offers little benefit if that duty is absent.

### Scenario B: Industrial Power/Control Wiring in Cable Trays

Review the tray wiring method, circuit duty, conductor loading, grouping, grounding and environment. Confirm a suitable tray-cable designation and certification for the actual route. MTW wording in a cable description does not establish tray suitability. Select shielding from the circuit's interference and termination needs rather than from either type name.

### Scenario C: Tray-to-Equipment Transition

Identify where the cable leaves the tray, how the transition is supported and protected, and how it enters equipment. Check whether TC-ER exposed-run provisions apply to that installation. Resolve fittings, bend limits, strain relief and potential damage before procurement. Do not infer a permitted unsupported distance from a general TC-ER description.

### Scenario D: European Machinery Exported to North America

Separate machine wiring from premises/field wiring and agree responsibilities with the project engineer and approving authority. Review the destination country and adopted requirements; U.S. installation assumptions do not automatically cover Canada. Ask whether both designations are actually required, which certification is mandatory, and whether each proposed size is covered. A European cable designation or CE marking alone does not establish the requested North American product certification.

## Specifying MTW / TC-ER Cable in Metric Sizes

International RFQs often combine North American type designations with European core notation. In notation using **G**, the total conductor count includes a green/yellow protective conductor, as illustrated in [LAPP's cable notation guidance](https://products.lappgroup.com/online-catalogue/power-and-control-cables/servo-applications/pvc-sheath/oelflex-dc-servo-700.html).

- **3G6 mm²:** three conductors in total, including the protective conductor, with a nominal 6 mm² conductor cross-section.
- **5G2.5 mm²:** five conductors in total, including the protective conductor, with a nominal 2.5 mm² conductor cross-section.

These are illustrative requests, not statements of DEV CABLE stock or availability under either standard. Confirm whether the circuit needs a neutral, the protective conductor size and identification, and how the supplier records grounds in its core count. “Three cores plus ground” is not 3G.

Keep the original metric requirement alongside any proposed AWG alternative. An approximate area conversion does not establish interchangeability: conductor construction, resistance, ampacity assessment, terminal range and certification coverage also matter. Obtain engineering approval for substitutions and verify that the selected metric or AWG variant falls within the proposed product's documented scope.

For the distinction between thermoplastic and cross-linked insulation systems, see our [PVC vs PE vs XLPE insulation guide](/blog/pvc-vs-pe-vs-xlpe-cable-insulation/). A material name alone cannot establish a type designation.

## MTW / TC-ER Cable RFQ Checklist

Give the supplier enough information to quote a defined construction and identify unresolved engineering points:

- **Application and location:** machine interior, panel, tray, equipment transition; fixed or moving duty and route sketch.
- **Required designation:** MTW, TC-ER or both, governing standards and project-specified editions.
- **Mandatory certification:** third-party listing/certification, destination acceptance and records required before approval.
- **Electrical duty:** rated voltage, circuit/load information and operating temperature; distinguish wet/dry, ambient and conductor requirements.
- **Conductors:** original mm² or AWG size, material, stranding, core count, neutral and grounding arrangement, identification and terminal constraints.
- **Construction:** insulation, jacket, shielding, shield termination and any drawing requirements.
- **Exposure:** oil/coolant, moisture, sunlight and named chemicals, including exposure temperature and duration.
- **Dimensions and movement:** outside-diameter limits, bending constraints, fittings and any continuous-flex duty requiring separate evidence.
- **Supply:** total length, individual cut lengths, packing and destination country.
- **Documents:** model datasheet/revision, marking legend, certification label/records, installation instructions and agreed inspection documents.

DEV CABLE can review project-specific industrial cable requirements and provide a technical quotation based on the requested construction, ratings and documentation. Any mandatory certification or listing must be confirmed for the proposed product.

## Standards and Further Reading

The linked UL standard overviews and marking guide support the product distinctions above. For installation review, consult [NFPA 70 / NEC](https://www.nfpa.org/codes-and-standards/nfpa-70-standard-development/70), including Article 336, and NFPA 79 where applicable. Use the edition adopted for the destination and the complete requirements; this comparison does not determine project acceptance.

## Frequently Asked Questions

### Is MTW cable the same as TC-ER cable?

No. MTW identifies machine-tool wiring covered by UL 1063; TC-ER identifies tray cable with exposed-run provisions under UL 1277. One designation does not establish the other.

### Can a cable be marked both MTW and TC-ER?

Yes, when the exact construction has been evaluated for both uses and its certification covers both. Check the model, cable marking, certification record and reel or package label together.

### Does TC-ER cable always require conduit?

No. Exposed runs can be permitted under the applicable installation rules. TC-ER is not unrestricted permission to omit conduit; review routing, support, protection, terminations and the adopted code.

### Can MTW cable be installed in cable trays?

MTW alone does not establish tray suitability. Check any additional cable designations and whether the exact construction and proposed wiring method are permitted by the applicable installation requirements.

### What documentation should I request for a dual-rated cable?

Request the exact model datasheet and revision, complete marking legend, reel or package certification label, relevant listing records and installation information. Confirm the ordered size and construction are covered by both claimed designations.