Before starting any project, it’s important to make sure that you’ve got the right tools for the job. One of my biggest personal pet peeves is having to stop mid-project and go to the hardware store to buy a tool because I need it immediately and can’t continue without it. After working on various solar arrays both in lab conditions and out in the field, I’ve started to notice a pattern of tools that I commonly needed emerge. I’ve listed them below and provided a little about why they’re important, as well as how much they can cost. I recommend having a toolbox with at the very least these essentials before attempting any solar-related project.
Digital Multimeter (DMM)
This is by far the most useful and handy tool that you will ever need for projects listed on this website. A DMM is basically your standard diagnostic tool for electrical-personnel, including a voltmeter, a current meter, resistance and conductivity tests. There are additional features for more advanced users that come standard with most modern DMMs, however the average PV-professional or even hobbyist will only need the basic voltage and current measuring features. For PV applications, make sure you get at least 1000V and 10A operating ranges.
Simply look up “multimeter” on Google and you’ll pretty much be taken straight to the source: Fluke. Sure, there are other DMM companies out there, however when it comes to quality, durability, and reliability, I’d trust the lab-rated Fluke over any $15 multimeter from Radio-Shack. I had a friend in college plug a small Radio-Shack multimeter into the wall and try to measure the voltage coming out of the grid. The device wasn’t able to handle the input and it exploded in his hands, leaving shards of burning plastic that had to be removed at the hospital. As a result, I have a strong distrust for any tool that I feel is “cheap,” and I wouldn’t recommend spending anything less than $100 for a good-quality DMM. My personal favorite is the Fluke 87 Digital Multimeter, as I’ve worked with one in some form or another for nearly a decade now and never had one fail on me yet. I’ve done my bit to put them through testing, dropping them off roofs, putting them in industrial ovens…I even accidentally set one on fire and it still worked afterwards.
At nearly $400, however, it’s obvious that Fluke products don’t come cheaply. If the price is just not agreeable, then I recommend trying out the Fluke 233 Remote Display DMM. It’s basically like the Fluke 87, except the display pops off and can be remotely controlled, so you don’t have to always in line of sight of whatever you’re measuring. It’s a nifty feature, but the main reason for this option is that it sells for about $300 instead.
Before moving on however, I need to point out that for Solar applications, the included current-measuring features of the multimeter alone is not sufficient. This is because most current-meters (also called Amp-meters or ammeters) require that the current being measured pass through the measurement device. This would mean that if I wanted to measure the current output of my array, I would need to run the entire array’s output in series through the DMM. That obviously isn’t practical or safe, so in order to measure current, another option is needed in the form of a “clamp meter.”
A clamp-meter is a special type of current-meter that uses Maxwellian mechanics to measure the current running through a wire without interfering with the circuit. This is important, as most of the circuits within a solar-array are not safe to touch and thus cannot be interrupted. The clamp meter side-steps the issue by allowing the user to enclose the wires within the clamp and release the wire again the same way when done.
Fluke offers a special clamp-meter attachment product, called the Fluke i410 AC/DC Current clamp. I recommend this model for those of you interested in residential and small-scale solar projects, at the Fluke i410 has a maximum current of 400A, which is way beyond anything you’ll encounter. However, if by some off chance you’re interested in the higher power applications, the Fluke i1010 allows you to go up to 1000A without a problem. There are special clamp-only meters that are sold separately to the DMM and are not attachments, however these can run upwards of $300 as well, so I recommend sticking with the clamp-meter attachment, as they operate virtually identically and the attachment is cheaper.
1000V Electrical Safety Gloves
I’ve been shocked and burned by electricity enough times in my life to know that safety gloves should always be toward the top of this list. I would normally advise anyone working with solar power to always wear gloves at all times, however I have found from experience that there are just times in the lab and out in the field where having gloves on for extended times makes things harder to deal with. Electrical safety gloves are usually some form of latex or rubber, so they allow absolutely no breathing whatsoever. After about two minutes, your hands start itching and get sweaty, and the rest of the time you’re in those gloves, you have this slimy, swampy feel to everything that is rather distracting.
I will however, urge anyone interesting in becoming a solar hobbyist in at least acquiring a pair of HV-safety gloves. I personally like to put them on for whenever I am connecting or disconnecting the DC-homeruns in an array or working inside a combiner box, basically, anywhere where I can accidentally touch an exposed energized surface. They’re not too expensive, and can generally be found for around $60 at electrical equipment distributors. If you’re having trouble finding a company of quality product, I’ve had success with Salisbury, a company that specifically caters to high-voltage linemen.
MC3 and MC4 Crimpers/Assemblers
If these terms sound foreign to you, then you’re not alone, these are rather esoteric tools that only industry installers would know about or have use of. The MC in the name designations above stand for “Multi-Contact,” which is the name of the company that somehow got the monopoly on all connectors for the DC wires coming out of the back of all PV-modules shipped to the United States. The 3 and 4 at the end designate the type of connector, but that’s not as important as the fact that these two connector types have become the industry standard for DC-wire connections. Sine this is the case, anyone looking to work with PV-modules in the United States is going to have to wire to one of these two connector types, hence the need to purchase the tools to fabricate these connections. I’ve stored and linked to a PDF file (here) of a catalog at Multi-Contact’s website that has all of the pieces needed to create the Male and Female ends of the connectors as well as the crimper tools and the assembly tools. It’s been a while since I’ve had to buy the tools, but the last time I did was in 2010 and the MC3 Crimper/Assembly tool combination ran about $700. For all of the tools and components for about 100 connectors, be prepared to spend about $2500 total.
Wire Strippers
A good chunk of the work involved in building a PV array is cutting and stripping the DC wiring that connects the strings of modules to the inverter. It seems like it’s a trivial matter, but I recommend putting some time into thinking about what kind of wire strippers you’re going to use. If you’d have asked me a few years ago, I’d have laughed and told you that there’s no difference, but after a few years of sore hands from using the wrong type of wire strippers, I can tell you that getting the right tool is essential to keeping your hands in good condition.
For most PV-solar applications, I find that these wire-strippers work pretty well. The larger gauge of the wires combined with the thicker 1000V insulation tends to make it a chore to use the standard plier-type wire strippers, as your thumbs can start hurting from the pressure you’ll have to exhort when pulling away the insulation sheath. These “one-handed” wire strippers combine all three actions of slicing, gripping, and pulling all at once, taking the strain off your hands.
Despite being quite handy for the larger wires, such as 12 AWG to 8AWG, these wire-strippers do have notable trouble with smaller wire sizes. That is because the wires are smaller and therefore provide less of a surface area with which to grip between the wire’s insulation and the tool’s holding surface. As a result, smaller wires tend to just slide around uselessly when placed inside wire strippers like this. This is why I suggest also having a pair of plier-type wire stripper around specifically for the smaller wire-sizes.
One tool that I feel the need to point out to avoid, however, is this “electrician’s multi-tool” combination wire-stripper, wire-cutter, crimper thing.
I can’t stand these things. They’re bad at wire-cutting, they’re bad at stripping wires, and they’re useless at crimping. It’s like they’re designed to require the user to be as strong as the Hulk, but made in such a flimsy way that the joint breaks if you breathe on it wrong. I’ve honestly tried giving this tool a fair chance thinking that I was just using it wrong, but after using it for the last three years, I can say with certainty that’s one tool I’ll never miss.
Cutting Tools: Box Cutter, Wire Cutters, Bolt Cutters
Aside from the wire strippers, it’s helpful to have a box-cutter for wires that are too large for wire stripper tools. For extremely large wires, such as 4/0 (pronounced “four-ought”, like “fore-thought” without the “th” sound) and above, the wire diameter can reach an inch or larger, so the easiest way to remove insulation is literally to just hack at it with a knife.
As for the wire cutters, the obvious reason to include them is to be able to quickly and easily sever wires of various sizes. For tackling the larger wires, such as the 4/0 mentioned above, I suggest also bringing along some large bolt cutters as well. These will help out greatly if/when you have to slice through about an inch of copper.
Hardware Sets: Screwdrivers, Allen-Wrenches, Socket Wrenches, Torx-Wrenches (star-sockets), Crescent Wrench, Needle Nose Pliers
Like it or not, hardware is everywhere, and just like most other things in this world, solar arrays are literally held together with nuts and bolts, screws and lugs. All of these are going to need specialized tools to handle. The Screwdrivers will most likely be used to get in and out of enclosures, however I’ve seen them nowadays with security screws or Torx-screws. Allen-Wrenches will be needed throughout the array, from lugs in the combiner box to casing screws on the inverter. Socket-wrenches are almost always needed to reach in between the modules and get at the hardware that holds them to the frame.
The Crescent wrench is to me simply a “universal wrench” as you can adjust its size to fit pretty much whatever hex-nut you need. Typically when working with nuts and bolts, two wrenches are need to tighten/loosen a connection. One for the bolt-head, and one for the nut. The crescent wrench is always a handy second choice when your socket wrench is otherwise used. The needle nose pliers are specifically for bending solid-core wires easily as well as other useful applications where you need to apply a lot of force in a small area. When in desperate times, I’ve even been known to use needle nose pliers in place of a crimper.
Basically, there are a variety of needs and locations that will need a variety of tools. My best suggestion is to have as many of these tools as possible in order to make access and repair go by more quickly. The sets mentioned above are what I would consider “essentials” that would be expected to appear at any/every array site.
Flashlight
At first, this seems like about as absurd as bring an umbrella to a pool party. Why would you need a source of light out there? Wouldn’t there already be a lot of light in the area, by definition…hence the solar? Well…true.
But you’re not out there to just stand in the sunlight, you’re likely out working with a solar array because it needs repair or you’re working on some project. That means you won’t be standing around in front of the solar array, where it’s bright and sunny…you’ll be standing underneath it, where it’s hot and dark, and frequently infested with spiders. Since most ground-mounted arrays conserve space by hiding their equipment under the modules, the modules will act like a large dark ceiling. Add to that the high-contrast conditions of the sunlight outside around the array, and you make a situation where it can be very difficult to read a screen or equipment display. The same goes for roof-mounted arrays, when dealing with someone’s attic.
Zip-ties
It’s simple things like zip-ties that make all the difference in the world. When dealing with installing or repairing wiring, it’s often frustrating not having the ability to control where you want the wire to hang somewhere or stay put, however with such minimalist designs for the frame, there are often few choices to accomplish this. Over the years, I’ve found it’s always handy to just have a few bags of these just lying around the bottom of my toolbox. That way, whenever I need to hold or move some wires, fixing the issue is as easy as reaching for a zip-tie or two instead of having to go to the hardware store.
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