Solar Power Wiring

[Martin B.]

Solar power seems to have it's own style of wire and fittings. I'd like to know: 1) How #12 awg PV (photo-voltaic) wire is different than other #12 awg wire.
2) Why MC4 connectors are used in solar wiring rather than other low voltage, high amperage connectors, such as Anderson Power Pole.

[steve dunham]

Originally Posted by Martin B.

Solar power seems to have it's own style of wire and fittings. I'd like to know: 1) How #12 awg PV (photo-voltaic) wire is different than other #12 awg wire.
2) Why MC4 connectors are used in solar wiring rather than other low voltage, high amperage connectors, such as Anderson Power Pole.

Standard #12 AWG building wire comes in solid and stranded and with multiple types of
insulation for different applications IE temperature , voltage , wet or dry locations ,direct burial ,insulation thickness . insulation color and sunlight resistance. Solar wire is rated for exposure to sunlight , wet locations and solar usage,
IE the conditions the wire will encounter in a solar application and are labeled / listed as such
The MC4 connectors are a code requirement . The terminations are
rated for there usage and provide a disconnecting means for isolating solar panels.
The Anderson power pole connectors are not rated for outdoor use , wet locations ,and have a limited voltage rating .
That being said I used 50 amp Anderson power pole connectors for my portable solar system without issue. The code differentiates little between solar used in a residential /commercial application or an RV application. IE One rule fits all. I would not use Anderson connectors where permanently exposed to the elements where they can degrade . In limited use such as in small portable RV system they probably do not present any major issues.

*Refer to Art 690 of the NEC for clarification*

[Ziggy]

MC4 connectors are (in theory) waterproof. You don't say if you are using a roof mounted or portable panel. This is what I use for a portable setup. 10 awg direct burial landscape wire connected to the panel with MC4 connectors (soldered). My controller is located inside the electrical cord bay. I have 5' of wire connected to the controller and an Anderson 50 amp connector on the other end. That allows me to easily keep the Anderson connector inside the bay if it is wet. Overall I'm happy but the landscape wire tends to get a little kinked up. In the future I would probably try something like this instead. 10/2 SOOW Portable Cord 600V UL/CSA | WireAndCableToGo.com

[Byron Kinnaman]

Any wire used on or near your trailer or tow vehicle should SAE GXL or SAE SXL wire. That's a wire with a teflon type insulation. It abrasive resistant and will NOT sustain fire. Required on all vehicles. SXL has a thicker insulation than GXL (Acronym explanation -- GXL == General purpose Cross Link SXL == Special purpose Cross Link)

[Raz]

My 60 watt (2x30) panel sits next to my trailer propped up by a 2x4. I cut the mc4 connectors off and soldered lug terminals to connect to the controller which is mounted on the back of one of the panels. I use 10 feet of 16 ga. lamp cord with a pair of oversized alligator clips to connect to the battery. When not in use the whole thing folds up and is stored in the pick up. No special connectors. No special wire. I'm living on the edge. Raz

[RogerDat]

Have heard of folks who have more respect for the proprieties than Raz use the connectors for 12 volt trolling motors available from boating stores to Walmart.

But I think those people are just putting on airs, lugs and clips are what made American campers great. Well that and the scenic locations, and smores, them too. And... JK don't you know.

[Raz]

All kidding aside Roger, if my panel were attached to my trailer, I would not be so casual. I have a great respect for the amount of energy stored in any lead acid battery. Raz

[RogerDat]

Originally Posted by P. Raz

All kidding aside Roger, if my panel were attached to my trailer, I would not be so casual. I have a great respect for the amount of energy stored in any lead acid battery. Raz

I have no doubt your "casual" approach is probably better implemented than some that employed the most expensive materials.

There was a long discussion on how to plug in the wires from a portable panel. One solution I thought was pretty decent was trolling motor plug. Does require one to do a good job of the splices but a nice solid fairly weather proof plug. With no way to cross the wires, plug ends only fit one way.

Me I think I would like the flexibility of a well done lugs and clips implementation. I could use it to charge any battery, tow vehicle, tractor in the shed, someone else's camper battery. Or move the whole thing to a sunny location if I was well back in the shade.

Built in is nice if it works for the way the person camps but making it permanent does demand a bit more investment in planning, materials and implementation.

[Raz]

Originally Posted by RogerDat

I have no doubt your "casual" approach is probably better implemented than some that employed the most expensive materials.

There was a long discussion on how to plug in the wires from a portable panel. One solution I thought was pretty decent was trolling motor plug. Does require one to do a good job of the splices but a nice solid fairly weather proof plug. With no way to cross the wires, plug ends only fit one way.

Me I think I would like the flexibility of a well done lugs and clips implementation. I could use it to charge any battery, tow vehicle, tractor in the shed, someone else's camper battery. Or move the whole thing to a sunny location if I was well back in the shade.

Built in is nice if it works for the way the person camps but making it permanent does demand a bit more investment in planning, materials and implementation.

The Renogy panels come with a small box on the back. When you remove the lid you find two cables, each with an mc4 connector. I unsoldered those and added my own wires. The back of the panel is aluminum and makes a nice place to attach the controller.

[RogerDat]

Nice Raz. That set up for two panels with the second panel red/black lines coming in from the left? Single batt line coming off the controller as the white lines?

What did you use to attach the controller with? Don't see any fasteners, double stick tape maybe?

[Raz]

Originally Posted by RogerDat

Nice Raz.

What did you use to attach the controller with? Don't see any fasteners, double stick tape maybe?

Same struff I use to keep the panels closed. Industrial adhesive Velcro