What types of Solar Cable does Allied Wire and Cable carry?
We offer three different kinds of solar power cable:
- UL Rated PV Wire – Photovoltaic wire
- USE-2 Solar Wire – Also known as RHW/RHH wire
- THHN Wire – General-purpose building wire
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What are the differences between USE-2 and Photovoltaic (PV) Solar Wire?
These two solar cables have varying constructions which give them different ratings and uses. USE-2 wire is crush and impact-resistant, but PV wire has thicker insulation. This gives it better sunlight resistance, flame resistance, and low-temperature flexibility. PV Wire also has a higher temperature rating. It is rated for 90°C in wet conditions and 150°C in dry conditions, whereas USE-2 wire is rated for 90°C in both wet and dry conditions. USE-2 solar wire is also often available in larger gauge sizes. It is suitable for use in PV module solar connectors and grounded PV arrays that do not exceed 600V. PV Wire is suitable for use in both grounded and ungrounded arrays. PV Wire can have a voltage rating of 600V, 1000V, or 2000V.
Can PV Wire and USE-2 Solar wire be used in above-ground or underground applications?
Single-conductor constructions of both solar cables are suitable for use in exposed outdoor arrays according to Sec. 690.31 (B) of the National Electrical Code (NEC). However, it is more common to choose PV Wire for exposed applications and USE-2 Solar Cable for underground use.
Are Allied Wire and Cable's PV Wires UL-approved?
Yes! Our PV Wire meets UL Style 4703. Our USE-2 solar cable also meets UL Styles, 4703, 44, and 854.
Can I use THHN Wire instead of USE-2 or PV Wire?
No. If standards specifically call for USE-2 or PV Wire, you cannot replace them with THHN Wire. While THHN wire can be used in solar connector applications, using it in place of designated Solar Cables can cause system failures due to their construction differences. For an in-depth look at how solar and wind energy have evolved, check out our insights on solar cable standards and wind standards.
Can I customize my Solar Cables?
Absolutely! Allied Wire and Cable offers many value-added services for all of our wire and cable. We offer custom printing and striping for all of our solar power cables. We also offer twisting and cut & strip for THHN Wire. Allied Wire and Cable can also help you design a completely custom solar cable.
What sizes do Solar Cables come in?
Solar cables come in a wide variety of AWG sizes. USE-2 solar cable is available from 4/0 to 14 AWG, PV Wire is available from 250 to 18 AWG, and THHN Wire is available from 1000 MCM to 14 AWG.
What is PV Wire?
Solar Panel PV Wire is a very popular solar power cable. This cable is used for interconnection wiring in photovoltaic systems. Most PV Wire features XLPE insulation and either bare or tinned copper conductors. This XLPE insulation makes the wire ozone, UV, sunlight, and moisture resistant. PV Wire is an extremely durable cable, designed specifically to withstand the environmental conditions of solar power applications.
It has a maximum temperature of +90°C in wet environments and +150°C in dry applications. It comes with varying voltage ratings, with either 600V, 1000V, or 2000V ratings. PV Wire can be used as an underground service entrance wire and is appropriate for both grounded and ungrounded PV arrays. These solar cables are also suitable for use in direct burial applications due to their thick insulation. PV Wire meets UL Standard 4703.
What is USE 2 Wire?
USE-2 Wire is another type of solar cable. It is an Underground Service Wire, meaning it is designed for and should only be used in grounded PV arrays. USE-2 Wire also features XLPE insulation and is available with a bare copper, tinned copper, or aluminum conductor. It is also often dual-rated as RHW/RHH Wire. This wire shares the high heat resistance of RHH wire and the water-resistance of RHW wire. This solar cable is crush, oil, gas, and impact-resistant. USE-2 wire also has a voltage rating of 600V and a temperature rating of 90°C in both wet or dry conditions. Because of this, it is ideal for more industrial applications.
While USE-2 solar cable is crush and impact-resistant, PV wire has thicker insulation and jacket. PV Wire also has better sunlight resistance, flame resistance, and flexibility at low temperatures. This makes PV wire the best choice for ungrounded PV arrays that encounter harsher weather conditions.
What is THHN Wire?
THHN wire is also commonly used in solar applications. It is a building wire used to carry electrical currents through power applications. Like USE-2 wire, THHN wire has a voltage rating of 600V and a maximum temperature of +90ºC in dry locations. However, it only has a maximum temperature of +75ºC in wet locations. Because of this, it should never be used in applications that specifically call for USE-2 or PV wire.
If a standard specifically calls for USE-2 or PV Wire, THHN wire cannot be used. These standards account for the extra strength and resistances found in PV and USE-2 Wire constructions. While THHN wire serves virtually the same purpose as these wires, its construction doesn’t account for the severe conditions of solar power applications. Using THHN wire in these applications may result in a system failure.
What is Type XHHW-2/XLPE Wire?
XHHW-2 Wire, also known as XLPE wire is a general-purpose wire that is suitable for applications in conduits, raceways, feeders, and branch circuits. It is also often found in power distribution systems in industrial, commercial, and residential buildings. "XHHW" is an acronym that stands for "High Heat-Resistant, Water Resistant". "XLPE" stands for "Cross-linked Polyethylene" which represents the Cross-linked Polyethylene that is used as insulation for XHHW-2 wire.
The thermoset material used in XHHW-2 wire provides excellent heat and water resistance. XHHW-2 building wire has a maximum temperature of 90°C in dry and wet locations, whereas Type XHHW wire can only be used in temperatures as high as 75°C in wet locations. The XHHW-2 specification has superseded the Type XHHW specification.
What are Common Applications of XHHW/XLPE Wire?
XHHW-2/XLPE wire is highly versatile and used in various applications across industrial, commercial, and residential settings. It is commonly found in power distribution systems, service entrance cables, and feeder circuits. Additionally, XHHW-2 wire is suitable for installations in conduits and raceways, making it ideal for use in wiring buildings, including high-rise structures. Its excellent resistance to heat and moisture also makes it suitable for environments where these factors are a concern, such as in underground or damp locations.
What are Alternatives for XHHW-2/XLPE Wire?
While XHHW-2/XLPE wire is a robust option for many applications, alternatives include other types of high-temperature resistant wires such as RHW-2 and USE-2 wires. RHW-2 wire, with its rubber insulation, offers similar heat and moisture resistance, making it another viable option for high-stress environments. USE-2 wire, designed for underground service entrance applications, also provides excellent durability and moisture resistance. For applications that do not require the high-performance characteristics of XHHW-2 wire, THHN/THWN wires can be considered as a more cost-effective option.
What are THHN and THWN wires?
THHN and THWN wires are single conductor, general-purpose building wires that are also suitable for installation in conduits and raceways. THHN and THWN wire are also suitable for use as machine tool, control circuit, or appliance wiring. Both THNN and THWN have PVC insulation with nylon jackets. The thermoplastic PVC insulation makes THHN and THWN wire have flame-retardant properties, while the nylon jacketing also adds resistance to chemicals such as gasoline and oil.
The "THHN" part of THHN wire stands for "Thermoplastic High Heat-Resistant, Nylon-Coated". "THWN" wire has the same properties, but the "W" part of THWN adds "Water resistance". The main difference between THHN and THWN wires are their maximum recommended operating temperatures in wet locations. While THHN wire is rated to be used in wet locations with ambient temperatures up to 75°C, THWN wire has a higher maximum recommended operating temperature of 90°C in both wet and dry environments. Although THHN and THWN wires can often be used interchangeably, it is important to ensure that THHN or THWN wire will perform it's best for your specific application. Please reach out and contact us with any questions.
What are Common Applications of THHN and THWN Wire?
THHN and THWN wires are widely used in building construction for electrical distribution systems. These wires are typically used for general-purpose wiring in residential, commercial, and industrial buildings. They are suitable for installation in conduit or other recognized raceways for services, feeders, and branch circuits. THHN/THWN wires are also frequently used for wiring machine tools, control circuits, and appliances due to their flexibility and flame-retardant properties.
What are Alternatives for THHN and THWN Wire?
Alternatives to THHN and THWN wires include TFFN and TFN wires, which are also thermoplastic insulated wires but are more flexible and used for lighter applications. For environments that require higher temperature ratings or additional durability, XHHW-2 wires provide a suitable alternative. MTW (Machine Tool Wire) is another alternative that offers superior flexibility and durability, making it ideal for industrial applications where frequent movement and bending are required. Lastly, NM-B (Non-Metallic Sheathed Cable) can be considered for residential wiring applications where conduit is not used.
What are the Differences Between XHHW-2/XLPE Wire and THHN/THWN Wire?
The major difference between XHHW-2/XLPE wire and THHN/THWN wire lies in their insulation materials. XHHW-2 wire uses Cross-Linked Polyethylene (XLPE), while THHN/THWN wires use Polyvinyl Chloride (PVC) with a nylon jacket. The XLPE insulation in XHHW-2 wire provides superior heat resistance and durability, making it more suitable for high-stress environments. In contrast, PVC insulation with a nylon jacket, used in THHN/THWN wires, is less expensive and still provides adequate performance for many general-purpose applications. Additionally, XLPE insulation does not emit toxic smoke when burned, making it a safer option in the event of a fire. XHHW-2 wire also maintains flexibility and durability in low-temperature applications, which can be advantageous over THHN/THWN wire.
Despite their differences, both types of wire are suitable for similar voltage ratings and applications, offering users various options depending on their specific needs. Allied Wire & Cable carries an extensive stock of both XHHW-2/XLPE and THHN/THWN type wires, including RoHS Compliant THHN Wire and Custom Wire configurations. If you have any more questions, please contact us today.
