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25' MC 4 Solar Panel (PV) Wire, UL4703
- Item #: STG.HRJ.10MC4.DJ.25
Designed to permit time-saving, dependable series cabling of solar panels and is compatible with the largest range of solar panel system products.
This 25' solar panel PV wire is used between photovoltaic arrays with Multi-Contact (MC4) cable connectors.
- Black solar panel cable
- UL listed 4703
- 10 AWG wire size,
- Sunlight resistant cables
Use to extend module output cables or cut anywhere along the wire to obtain the needed length of male and female cable to run from string of modules to a combiner box or to a longer cable.
Differences Between PV Wire and USE-2 Wire
Whereas USE-2 wire has long been accepted for PV module interconnections, PV wire is newly introduced in the 2008 edition of NEC. Though their construction and performance requirements are similar, some variations do exist due to their unique installation conditions. Below is a comparison of these two types of wires, based on their usage, construction and testing requirements.
• Usage
PV wire, with 90ºC wet rating and up to 150ºC dry rating, is dedicated for interconnecting PV modules. USE-2 wire is designated as underground service entrance cable typically for connecting to the terminals of service equipment. It is limited to installations in maximum 90ºC wet and dry conditions.
Both USE-2 wire and PV wire can be rated 600 V. However, PV wire can also be rated 1000 V and 2000 V to accommodate photovoltaic modules intended for use in systems with a system voltage greater than 600 V.
Per the NEC, USE-2 wire is suitable for use in grounded PV arrays only but PV wire can be used within both grounded and ungrounded PV arrays.
• Construction
PV wire comes with a thicker insulation or jacket to provide additional mechanical protection against the physical abuse that USE-2 wire is typically protected from.
PV wire has to employ stranded copper conductors to make it flexible for the intended application. On the contrary, USE-2 wire can employ either solid or stranded conductors made of copper, copper-clad aluminum or aluminum because it is typically installed in locations not subject to movement or mechanical damages.
The minimum conductor size for USE-2 wire is 14 AWG but PV wire can employ a smaller conductor size down to 18 AWG.
• Insulation and Jacket Materials
Both PV wire and USE-2 wire use thermoset insulation and jacket typically made of XLPE or EPCV. Nevertheless, other thermoset materials such as CP over EP, CP over EPCV, SBR/IIR/NR and EP are also available. PV wire may also be constructed similar to Type UF but using an additional 15 mils more of 90ºC wet and dry rated integral PVC insulation and jacket.
• Testing Requirements
Considering USE-2 wire is typically installed underground or in similar locations where a flame may not propagate but PV wire can be installed exposed, a flame test is only required for PV wire. On the other hand, the overload test and the mechanical abuse tests including crushing resistance and impact resistance are just applicable to USE-2 wire.
As for sunlight resistance and flexibility at low temperature tests, PV wire has to comply with more stringent requirements. It has to undergo 720-hour weatherometer and -40ºC cold chamber conditioning respectively. The requirements for USE-2 wire are 300-hour weatherometer and -25ºC cold chamber conditioning.
In summary, PV wire has superior sunlight resistance and low-temperature flexibility when compared to USE-2 wire, in addition to a thicker insulation or jacket and a proven level of flame resistance. Given PV wire can facilitate the use of ungrounded PV arrays as well as transformerless inverters, it is anticipated to become popular for module interconnections soon.
For more information on UL certification service for PV wire, please contact your local UL office.
Technical content of this article is provided by Leo Chung, UL Conformity Assessment Services, Hong Kong
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- Part No.: STG.HRJ.10MC4.DJ.25
