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Easy to follow Step by Step Guide to setting up a solar energy system
Quick and easy projects for your Solar Energy System that will save you money!
Easy Solar Projects
Project #2 : Mini Junction Box
While this is really just a 'mini' project, this junction box is a very handy item to have. It securely and safely replaces those cumbersome and unreliable wire nuts. With the optional cover and gasket, this box is waterproof and can be used outdoors to combine multiple solar arrays or anything you want connected in parallel. I use mine to connect my 4-panel solar array and the 2 solar panels on my house. The Combiner Box is used on my 4-panel array to combine those 4 solar panels together.
Parts required : For this project you will need a plastic junction box like in the photo, a ground bar, and optionally, a cover plate with gasket. The junction box is made by Carlon and is available at Home Depot (034481084013) for $4.49. You can use any size ground bar that fits, but I bought a single 21 terminal bar (782114793398) for $3.98 and cut it in half with a hack saw. The idea is to use a ground bar long enough to just drop into the slots of the junction box and no fastening is required. To make it waterproof and give it a finished look, the cover plate is $2.96.(034481115120)
Internal Wiring : Cut the long ground bar in half or drop 2 shorter ones into the slots like in the photo. They fit nicely and the wires themselves hold everything in place. I have shown here 4 Gauge AWG wires for the large output wires and a 10 Gauge and 6 Gauge pair of Red(+) & Black (-) wires to demonstrate the wide range of sizes possible. If you need more room, you can drill holes for more wires. The bar on the left holds all of the negative wires and the bar on the right holds all of the positive wires.
Finished Mini Junction Box : Here is the finished junction box shown with the optional cover plate installed. This makes it waterproof and gives it a nice finished look. The total cost for this project as shown is $11.43 at Home Depot, prices as of March 22, 2006. Now, don't you think that beats the xxxx out of wire nuts? And yes, I do shop at Home Depot a lot. They have a wide range of products and at the right price... usually. Hope you like the 'Mini Junction Box'.
DISCLAIMER : Alway make sure that all of your equipment is properly fused and grounded for safety. Also, be sure to read and follow the advice and instructions that come with your equipment. While our projects have actually been constructed and tested under actual operating conditions, we do not guarantee that they will meet all electrical codes in all locales. Nor do we suggest that our advice supercedes the recommendations of a licensed electrician. Hey, we're just trying to help!

Design your system quickly with our Interactive Design Tools
(Note : These design tools require javascript to be turned on in your browser)
* Check out our easy point & click System Sizing Estimator to quickly & easily calculate the number of solar panels and storage batteries you'll need for a wide range of system sizes.
* Our Battery Bank Design Tool will take the confusion out of wiring up your battery bank. Use 2, 4, 6, or 12 volt batteries to build a system voltage of 12, 24, or 48 volts using series and parallel wiring with just 4 clicks. Battery bank capacities from 300 AmpHours to over 4000 AmpHours are displayed graphically so you can see exactly how to wire the batteries together.
* This Wire Size Calculator will allow you to quickly find the correct wire size in AWG (American Wire Gauge) based on the distance to your solar panel array & the amount of amperage your panels put out. No math required!

New Feature!  Check out our new feature Solar Projects where you can build easy, do-it-yourself projects for your solar power system to save money and have fun doing it!

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