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The panels sit on the far end of the RV roof, the charge controller waits by the battery bank, and the cable that came in the box stops short of the run. A solar wire size calculator closes that gap: it takes the voltage and current of the run and the length of the cable, and gives back the gauge that keeps the loss low. The steps below show what to feed it, how to read what it gives back, and how to match the answer to a cable that states the same figures.
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What a solar wire size calculator needs
Three figures go in: the voltage of the run, the current it carries, and the length of the cable from the panels to the controller. Read the voltage and the current from the labels on the panels and the controller, and measure the run along the path the cable will take, not in a straight line. The calculator then gives back a gauge, usually in AWG, and the loss it expects on that run. A thicker gauge loses less over the same length, which is why the Feotech listing states that longer distances require thicker wires to minimize voltage drop. See the parts of a solar power system for where each figure sits.
How to read the result
Take the gauge the calculator gives and match it to a cable that states the same gauge. Then check the two ratings that sit beside it: the voltage rating and the current rating. The SJZ SUN RUN cable (on Amazon) states 1500V DC with a max of 1800V and a rated current of 50A, while the Kimbluth cable (on Amazon) states a max voltage of 600V. If the run needs more than the cable states, the cable does not fit, whatever the gauge says. A solar wire size chart gives the same answer in table form: find the run length and the current, then read the gauge. See the 10 AWG vs 14 AWG solar cable comparison for how two gauges differ on the same run.
The gear: cables that match the numbers
The 4 cables below state the gauge, length and ratings the calculator asks for, so match the calculator result to the cable that states the same figures.
| # | Product | Solar Score | Buy |
|---|---|---|---|
| 1 |  SJZ SUN RUN 100FT 10AWG Cable | 9.7/10 | Buy on Amazon |
| 2 |  Kimbluth 100FT 10AWG Cable | 9.6/10 | Buy on Amazon |
| 3 |  Feotech 40FT 10AWG Cable | 9.5/10 | Buy on Amazon |
| 4 |  MOOKEERF 100FT 10+14AWG Cable | 9.5/10 | Buy on Amazon |
SJZ SUN RUN 100FT 10AWG Cable
A 100 ft red and black pair of 10 AWG tinned copper cable with IP68 connectors, TUV certification and a 1500V DC rating.
Pros
- TUV certified to EN50618:2014 as stated in the listing
- IP68 pre-installed female and male connectors
- Rated 1500V DC with a max of 1800V and a rated current of 50A
- 100 ft red plus 100 ft black with dust plugs and cable ties included
Cons
- No warranty term is stated
- Fixed at 100 ft per side, so a short run leaves spare cable to manage
- Only 10 AWG is offered in this listing
- A system above the stated 1500V DC rating needs a different cable
Detailed Review
The listing states 10 AWG tinned copper wire with XLPE dual insulation and PPO connectors, TUV certification to EN50618:2014, IP68 connectors, a rated voltage of 1500V DC with a max of 1800V, a rated current of 50A, 84 strands of 0.285 mm wire, conductor resistance of 3.39 ohms per km at 20 C, an operating range of -40 F to 248 F and -40 C to 120 C, and a service life of 25+ years. It includes 100 ft of red cable plus 100 ft of black cable with 2-pair pre-installed connectors, dust plugs and cable ties. The title, bullets and spec table agree on the gauge, length and ratings.
Who it's for: long runs on RVs, boats and off-grid arrays where the stated 1500V DC and 50A ratings match the system. Who should skip it: short runs where 100 ft per side leaves spare cable, or systems above the stated ratings.
Its Solar Score of 9.7/10 comes from performance 32/35, build 22/25, value 21/25, safety 9/10 and warranty 0/5: 84 of 100 points, placed on our 9.2 to 9.8 scale.
Key Specifications
| Gauge | 10 AWG, tinned copper |
|---|---|
| Length | 100 ft red + 100 ft black |
| Rating | 1500V DC, max 1800V, 50A |
| Connectors | IP68, 2-pair pre-installed |
Figures as published on the retailer listing, collected 12 November 2026. Performance figures are manufacturer rated.
Safety and Warranty
What this listing states. TUV certified to EN50618:2014, IP68 connectors, rated 1500V DC and 50A stated, so safety scores 9 of 10. No warranty term, so warranty scores zero. See How We Pick.
Size and fuse it. Match wire gauge and fuses to the current the maker specifies, keep MC4 connectors matched to the same type, and keep connections dry and strain relieved.
This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.
Kimbluth 100FT 10AWG Cable
A 100 ft length of 10 AWG tinned copper cable with IP68 connectors, a 600V max rating and a 20+ year service life.
Pros
- 105 strands of tinned copper wire stated
- IP68 proof level stated for the connectors
- Max voltage up to 600V stated
- Service time up to 20+ years stated
Cons
- No warranty term is stated
- Max voltage of 600V, below the 1500V DC rating of the SJZ SUN RUN cable
- Only 10 AWG and 100 ft in this listing
- No TUV or other certification is stated
Detailed Review
The listing states 10 AWG cable with 105 strands of tinned copper wire, PVC insulation with UV resistance, IP68 proof level, a max voltage of 600V, a working temperature of -40 F to 224 F and -40 C to 105 C, and a service time of 20+ years. Both ends carry male to female solar connectors with a built-in lock. The title, bullets and spec table agree on the gauge and length.
Who it's for: 100 ft runs on RVs, boats and home arrays within the stated 600V rating. Who should skip it: systems above 600V, or runs that need a stated certification.
Its Solar Score of 9.6/10 comes from performance 29/35, build 21/25, value 20/25, safety 8/10 and warranty 0/5: 78 of 100 points, placed on our 9.2 to 9.8 scale.
Key Specifications
| Gauge | 10 AWG, 105 strands tinned copper |
|---|---|
| Length | 100 ft |
| Rating | Max voltage 600V |
| Connectors | IP68 male to female |
Figures as published on the retailer listing, collected 12 November 2026. Performance figures are manufacturer rated.
Safety and Warranty
What this listing states. IP68 proof level and max voltage up to 600V stated, so safety scores 8 of 10. No warranty term, so warranty scores zero. See How We Pick.
Size and fuse it. Match wire gauge and fuses to the current the maker specifies, keep MC4 connectors matched to the same type, and keep connections dry and strain relieved.
This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.
Feotech 40FT 10AWG Cable
A 40 ft twin wire pair of 10 AWG tinned copper cable with 6 pairs of IP67 connectors for shorter runs.
Pros
- 6 pairs of IP67 male and female connectors included
- Tinned copper with weather-resistant insulation stated
- 40 ft length suits shorter runs with less spare cable
- Twin wire pair keeps both conductors in one run
Cons
- No warranty term is stated
- No voltage or current rating is stated
- IP67 connectors, below the IP68 connectors on the other picks
- 40 ft suits shorter runs; a longer run needs the 100 ft listings
Detailed Review
The listing states 10 AWG (6 mm²) tinned copper wire in a 40 ft twin wire pair, with 6 pairs of IP67 male and female solar connectors and weather-resistant insulation. It states that longer distances require thicker wires to minimize voltage drop, and that the wire suits outdoor, automotive, RV, boat and marine use. No voltage or current rating is stated. The title, bullets and spec table agree on the gauge and length.
Who it's for: shorter runs where 40 ft reaches and IP67 connectors suit the install. Who should skip it: runs over 40 ft, or systems that need a stated voltage and current rating.
Its Solar Score of 9.5/10 comes from performance 27/35, build 20/25, value 19/25, safety 7/10 and warranty 0/5: 73 of 100 points, placed on our 9.2 to 9.8 scale.
Key Specifications
| Gauge | 10 AWG (6 mm²), tinned copper |
|---|---|
| Length | 40 ft |
| Connectors | 6 pairs, IP67 male/female |
| Insulation | Weather-resistant |
Figures as published on the retailer listing, collected 12 November 2026. Performance figures are manufacturer rated.
Safety and Warranty
What this listing states. IP67 connectors stated, so safety scores 7 of 10. No warranty term, so warranty scores zero. See How We Pick.
Size and fuse it. Match wire gauge and fuses to the current the maker specifies, keep MC4 connectors matched to the same type, and keep connections dry and strain relieved.
This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.
MOOKEERF 100FT 10+14AWG Cable
A 100 ft one-piece solar extension cable with 10AWG and 14AWG conductors, IP68 connectors and a flame-retardant PVC VW-1 jacket.
Pros
- IP68 male and female connectors installed at the wire ends
- Flame-retardant PVC VW-1 jacket stated
- One-piece design with no separate black and red wires to manage
- Connectors join multiple cables together for longer length
Cons
- No warranty term is stated
- Mixed 10AWG and 14AWG conductors: the thinner 14 AWG leg sets the limit for the pair
- No voltage or current rating is stated
- No strand count or conductor resistance figure is stated
Detailed Review
The listing states a 100 ft one-piece solar extension cable with 10AWG and 14AWG tinned copper conductors, IP68 male and female connectors, a flame-retardant PVC VW-1 jacket, and heat resistance to 80 C. The title and bullets agree that the pair mixes 10AWG and 14AWG, so the thinner 14 AWG conductor sets the limit for the run. No voltage or current rating is stated.
Who it's for: installs where the one-piece orange cable suits the run and the 14 AWG leg fits the current. Who should skip it: runs that need a matched pair of 10 AWG conductors.
Its Solar Score of 9.5/10 comes from performance 24/35, build 20/25, value 19/25, safety 7/10 and warranty 0/5: 70 of 100 points, placed on our 9.2 to 9.8 scale.
Key Specifications
| Gauge | 10AWG + 14AWG, tinned copper |
|---|---|
| Length | 100 ft |
| Connectors | IP68 male and female |
| Jacket | Flame-retardant PVC VW-1 |
Figures as published on the retailer listing, collected 12 November 2026. Performance figures are manufacturer rated.
Safety and Warranty
What this listing states. IP68 connectors and flame-retardant PVC VW-1 stated, so safety scores 7 of 10. No warranty term, so warranty scores zero. See How We Pick.
Size and fuse it. Match wire gauge and fuses to the current the maker specifies, keep MC4 connectors matched to the same type, and keep connections dry and strain relieved.
This is general buying information, not professional advice. Follow each product manual and local rules, and see our Safety Disclaimer.
As an Amazon Associate I earn from qualifying purchases.
Where the points went
The Solar Score weighs performance, build, value, safety and warranty. For cables, safety means the stated connector code and the voltage and current ratings, and build means the conductor metal and the jacket. None of the cables here states a warranty term, so warranty adds nothing to any score. How we pick explains the weights.
Match the cable to the run
Start from the run length
Measure the run first. The Feotech cable (on Amazon) runs 40 ft, while the SJZ SUN RUN, Kimbluth and MOOKEERF cables run 100 ft, so the run length decides which of them reaches. A run that needs more than the cable states needs a longer cable or a joined pair, and the MOOKEERF listing states that its connectors join cables together for longer length. For an RV install, see the solar setup for RV guide.
| Cable | Gauge | Length | Voltage and current stated | Amazon |
|---|---|---|---|---|
| SJZ SUN RUN 100FT 10AWG Cable | 10 AWG | 100 ft red + 100 ft black | 1500V DC, 50A | View on Amazon |
| Kimbluth 100FT 10AWG Cable | 10 AWG | 100 ft | Max 600V | View on Amazon |
| Feotech 40FT 10AWG Cable | 10 AWG | 40 ft | Not stated | View on Amazon |
| MOOKEERF 100FT 10+14AWG Cable | 10AWG + 14AWG | 100 ft | Not stated | View on Amazon |
Check the voltage and current ratings
Match the ratings to the run, not just the gauge. The SJZ SUN RUN cable states 1500V DC with a max of 1800V and a rated current of 50A, and the Kimbluth cable states a max voltage of 600V. The Feotech and MOOKEERF listings state no voltage or current rating, so check the manual for the panels and the controller before using either on a run that needs one.
Pick connectors that suit the install
The connectors on these cables come pre-installed, male and female, so the run needs no extra assembly. The SJZ SUN RUN, Kimbluth and MOOKEERF cables state IP68 connectors, and the Feotech states IP67 connectors with 6 pairs in the box. See the solar panel connector types for how the connector styles differ. If the run connects to home wiring, a licensed electrician should install it.
FAQ: power away from the grid
What size wire do I need for solar panels?
It depends on the voltage, the current and the length of the run, so feed those figures into a solar wire size calculator and match the gauge it gives to a cable that states the same gauge. The cables here state 10 AWG, except the MOOKEERF, which states 10AWG and 14AWG in one cable. Check the voltage and current ratings beside the gauge before you buy.
Does a longer cable run need thicker wire?
Yes. The Feotech listing states that longer distances require thicker wires to minimize voltage drop, and the SJZ SUN RUN listing states that its 10 AWG tinned copper cable offers low-loss long-distance transmission. Measure the run, feed the length into the calculator, and use the gauge it gives.
Do solar extension cables come with connectors fitted?
Yes, on the cables here. The SJZ SUN RUN cable comes with 2-pair pre-installed female and male solar connectors, and the MOOKEERF cable (on Amazon) has a male and a female connector installed at the wire ends. The Feotech cable comes with 6 pairs of IP67 male and female connectors.
Can I join two solar extension cables for a longer run?
Yes, when the connectors match. The MOOKEERF listing states that its connectors join multiple cables together for longer length, and the Feotech listing states 6 pairs of connectors in the box. Match the gauge and the ratings on both cables before joining them.
Related solar guides
See the solar wire size calculator guides, the solar setup for RV guide and the solar charger calculator.
