Quick answer: UL1007 is commonly supplied as 80°C, 300 V PVC-insulated appliance wire; UL1015 is commonly sold as 105°C, 600 V PVC-insulated appliance wire. But the bigger manufacturing issue is often insulation outside diameter (OD). At the same nominal AWG, a UL1015 construction can be substantially thicker than a UL1007 construction. Changing the wire can therefore affect terminal insulation support, connector exits and routing. A matching AWG does not guarantee a drop-in replacement.
For an OEM buying a custom wire harness, the correct choice is the wire and termination combination that meets the drawing, service conditions and approved component specifications—not automatically the style with the higher rating.
1. UL1007 vs UL1015: Key Differences
| Feature | UL1007 | UL1015 |
|---|---|---|
| Commonly sold temperature rating | 80°C | 105°C |
| Commonly sold voltage rating | 300 V | 600 V AC |
| Insulation family | PVC | PVC |
| Typical insulation construction | Thinner-wall construction | Thicker-wall construction at a comparable conductor size |
| Common selection consideration | Compact internal wiring where the approved ratings are suitable | Internal wiring needing the specified insulation construction or higher published ratings |
| Critical production check | Conductor, insulation OD and contact fit | Conductor, larger insulation OD and contact fit |
These are representative commercial products, not a statement that every manufacturer supplies identical constructions. In particular, the historical UL Style 1015 listing includes 80°C, 90°C and 105°C variants; consult the selected manufacturer's current documentation and applicable UL records for the specific product.
2. What Do the Temperature and Voltage Ratings Tell You?
A wire style helps identify the construction and rating category. It does not independently qualify a finished harness for a particular appliance, temperature zone or connector system.
For example, specifying 105°C UL1015 wire does not establish that the connected terminal, plastic housing, protective tubing or complete assembly can operate at 105°C. Each part must be checked at its actual installed location. For more on system-level temperature limits, see our high-temperature wire selection guide.
A higher temperature or voltage rating also does not, by itself, mean higher allowable current. Current capacity depends on the conductor and installation conditions, including bundling, ambient temperature, allowable temperature rise and terminal limits.
3. The Manufacturing Difference: Insulation Thickness and Outside Diameter
One way to see the physical difference is to compare the same nominal conductor gauge in a published supplier catalog.
Taiwanese wire manufacturer Tong Wu's UL1007/UL1015 product table lists these nominal dimensions:
| Manufacturer's example | Nominal gauge | Approx. insulation wall | Approx. finished OD |
|---|---|---|---|
| UL1007 stranded PVC wire | 22 AWG | 0.41 mm | 1.60 mm |
| UL1015 stranded PVC wire | 22 AWG | 0.79 mm | 2.40 mm |
The 0.80 mm difference in nominal outside diameter is substantial when a wire must enter a compact housing or be held by a crimp terminal's insulation-support wings. These figures belong to the cited supplier's catalog. They are not measurements of Shengxin stock, universal UL dimensions or accepted tolerances for a customer order. The published table also lists different strand constructions for its two 22 AWG examples, so its conductor details must not be assumed interchangeable without supplier confirmation.
The Impact on Crimping and Assembly
A terminal usually has separate design limits for the conductor crimp and the insulation support. Two wires may both be labeled 22 AWG, while their insulation diameters differ enough that one falls outside the approved insulation range of the same contact.
The resulting concerns can include:
- Insulation wings that do not grip the wire correctly.
- A wire that is difficult to route through a housing exit, grommet or sleeve.
- Different stripping or crimp-tool setup requirements.
- Increased bundle diameter and a different bend path.
A matching AWG does not guarantee a drop-in replacement. Check the contact manufacturer's approved conductor and insulation ranges, application tooling and the customer's drawing. Our electrical terminal types guide explains how crimp integrity and terminal retention must be evaluated separately.
4. Can UL1015 Replace UL1007 in the Same Connector?
A substitution needs a technical review and customer approval. Before proposing a change, verify the following:
- Electrical conditions: Does the replacement meet the specified voltage, temperature, insulation and application requirements?
- Conductor construction: Is the conductor size, stranding and conductor material compatible with the approved terminal?
- Insulation OD: Does the actual purchased wire fall within the contact's approved insulation-support range?
- Termination tooling: Can the specified terminal and applicator process the proposed wire correctly?
- Housing and routing: Does the completed wire fit the housing exit, sleeves, clamps and allowed bend route?
- Change control: Has the OEM approved the alternate wire and any necessary terminal or process changes?
A thicker wire may fit through an opening but still fail an approved terminal-crimp requirement. Physical assembly alone is not evidence that a substitution is acceptable.
5. Is UL1015 Always the Better Wire?
No. The wire should be selected against actual product requirements.
A thicker insulation construction can be useful where its required rating and construction are appropriate, but it can also occupy more space, change termination settings and increase routing difficulty. Conversely, a smaller UL1007 wire is not automatically acceptable where the product requires different electrical, thermal or safety performance.
When the drawing already specifies an approved style and manufacturer, a proposed change should be treated as an engineering decision, not a purchasing shortcut.
6. How These Styles Appear in Customer Harness Drawings
On the custom harness drawings we receive, the two styles often serve different roles rather than appearing as direct alternatives. UL1007 is frequently specified in smaller conductor sizes such as 22 or 24 AWG, including compact wire-to-board assemblies. UL1015 more often appears in thicker internal wiring such as 18 or 20 AWG, with larger connector or terminal arrangements.
For example, drawings may pair UL1007 with small-pitch XH-Type or PH-Type connector systems, while UL1015 may appear alongside 3.96 mm VH-Type housings, 0.187-inch and 0.250-inch quick-disconnect terminals, or ring terminals. Drawings that use both styles usually assign them to different circuits. These are observed drawing patterns, not compatibility rules: each wire-to-terminal combination must still be verified against its actual part numbers, conductor construction and insulation diameter.
The distinction matters during sourcing. If a customer wants to change a wire style, ask whether the required wire function, terminal and housing remain the same. Sometimes the correct solution is to retain the approved wire, not to change the entire termination system merely to obtain a higher catalog rating.
7. What to Specify on the Drawing or BOM
A useful wire callout identifies more than the UL style and AWG.
| Drawing / RFQ item | What to provide |
|---|---|
| Wire identification | UL style and exact manufacturer part number where specified |
| Conductor | AWG or mm², strand construction and conductor finish |
| Insulation | Material, color, finished OD limits when critical and required ratings |
| Terminations | Complete contact and housing part numbers, plus cavity/pin assignment |
| End preparation | Cut length, strip length, crimping or solder-dipped end requirements |
| Processing | Applicable crimp application specification and approved tooling/process |
| Acceptance | Dimensional tolerances, inspection plan and project-specific tests |
| Change approval | Whether alternative styles, suppliers or contact parts may be proposed |
If a wire specification says only “UL wire, 22 AWG,” the quotation may depend on unresolved assumptions. Our custom wire harness drawing guide explains how to organize the drawing and BOM. For conductor surface finishes, read tinned copper vs bare copper wire; conductor tin plating and solder-dipped wire ends are different requirements.
8. From Drawing Review to Production at Shengxin
For a build-to-drawing assembly, Shengxin reviews the specified wire, terminal and housing combination before production and confirms any mismatch with the customer. That review can include the purchased wire's dimensions, the contact's applicable crimp ranges, processing requirements and available assembly space.
In practice, the important question is not merely whether UL1007 or UL1015 can be cut and stripped. It is whether the complete proposed termination is compatible with the approved BOM and the intended installation. A supplier change or revised wire style should be documented and approved before production rather than silently substituted.
For examples of both formats, see our terminal wire assemblies, which include quick-disconnect and ring-terminal leads, and our wire-to-board connector harnesses built on XH-Type, PH-Type and VH-Type housings.
9. Frequently Asked Questions
What is the difference between UL1007 and UL1015 wire?
Both are commonly supplied as PVC-insulated appliance wire, but their commonly sold temperature and voltage ratings differ and UL1015 typically has a thicker insulation construction at a comparable AWG. The finished OD can affect crimping and connector fit.
Is UL1015 always 105°C and 600 V?
105°C and 600 V AC is a common commercial specification. However, the historical UL Style 1015 description also lists 80°C and 90°C variants. Confirm the actual selected manufacturer's marking, datasheet and current recognition information.
Can I substitute 22 AWG UL1015 for 22 AWG UL1007?
Not automatically. A matching AWG does not prove the insulation diameter will fit the existing terminal, housing or assembly route. Check the approved contact and wire data, then obtain customer authorization for the change.
Does UL1015 carry more current than UL1007 at the same AWG?
Not solely because of the style designation. Current suitability is an application-level engineering question involving conductor, installation, thermal conditions and terminations. Do not use the voltage rating as an ampacity figure.
Is the copper in UL1007 or UL1015 always tinned?
No single conductor finish should be assumed merely from the UL style. Check the actual supplier construction and customer BOM. Also distinguish a tin-coated conductor from a solder-dipped prepared end.
How do I measure a wire's insulation OD?
Use a suitable caliper across the unstripped insulation, without squeezing the soft PVC enough to deform it. Check the instrument's zero, use gentle contact, repeat at several points and compare the result with the supplier's documented tolerances. A handheld reading alone does not establish material certification or terminal compatibility.
Conclusion
The practical difference between UL1007 and UL1015 is not limited to temperature and voltage ratings. Insulation OD, approved contact fit, routing and the customer's controlled BOM determine whether a wire can be used in a specific harness assembly.
For an OEM quotation, share your wire style, exact material specification where available, connector and terminal part numbers, assembly drawing and operating conditions. Send Shengxin your drawing for review so potential wire and termination mismatches can be identified before sampling.
