Hey everyone, if you’ve ever shopped for installation terminal blocks for a project—whether it’s wiring up a tiny home office setup or a full industrial control panel—chances are you’ve stared at a shelf of standard-length blocks and thought, “This just isn’t gonna fit what I need.” I’m part of a terminal block supply company, and let me tell you, this is one of the most common questions we get from electricians, engineers, and even weekend DIYers: Do installation terminal blocks come in custom lengths? Installation Terminal Block
Let’s cut right to the chase—short answer is: Yeah, they do. But it’s not as simple as picking a random number and hitting order. Most people first think of the off-the-shelf (OTS) blocks you grab at the local hardware store or big-box industrial supply: 10-position, 20-position, whatever is already assembled in a neat row on a carrier. Those are perfect if your wire count lines up exactly with those pre-made lengths, but let’s be real—projects rarely work that neatly. I remember a guy hit us up last month, panicked, because he had to wire a small control module for a brewery’s pump system, and his cabinet had a weird 17-wire gap between two sensors. All the standard blocks were 10 or 20 positions, so he’d have extra space to fill with unused blocks, which isn’t just messy—it’s a fire risk if loose wires or debris get in the gaps. That’s exactly where custom length terminal blocks save the day.
First, let’s clarify what we mean by “installation terminal blocks” here—these are the ones used for connecting, insulating, and securing electrical wires in permanent setups: control panels, building wiring, machine tools, that kind of thing. They’re different from the small, disposable ones you use for temporary test wires. So when we talk custom lengths for these, we’re talking adjusting how many individual positions (each one holds one wire) are in a single block assembly, not like cutting a solid plastic bar down. Most custom terminal blocks are made on a modular system anyway—each position is a separate unit that clips together, right? So if you need 7 positions instead of a pre-made 10, you just skip 3, and that’s your custom length.
But wait, why would you even need a custom length vs. mixing and matching standard ones? Let’s break down the use cases that make custom blocks non-negotiable. For industrial projects, like that brewery cabinet I mentioned earlier, space is at a premium. Control panels often have tight, measured cutouts for components—if your terminal run is just an inch shorter than a standard 20-position block, adding an extra block to make up the length might force the entire panel to shift, which throws off nearby switches or PLCs (programmable logic controllers). That’s hours of rework, no one wants that. Then there’s renovation work: old commercial buildings that had weird wiring runs back in the 80s, when standard wire counts weren’t consistent. Electricians have to fit terminal blocks into spaces that were never designed for them, so a custom length that fits exactly avoids messy wiring hacks like cramming extra blocks or leaving empty positions. Even hobbyists building custom gear—like a small solar setup for a camper—might need a custom run to fit their battery compartment, not waste space on unused terminal positions.
Now, don’t get it twisted—custom lengths aren’t for every job. If you’re wiring a basic home circuit that needs 12 wires, a 12-position standard block is cheap and easy to get, no need to go custom. The tradeoff with custom is that it’s not OTS, so it takes a little longer (usually 3 to 7 business days for standard custom runs, depending on volume) and there’s a minimum order sometimes, but it’s way better than dealing with the headache of ill-fitting blocks. I should also mention that not all terminal block suppliers offer custom lengths—some only stick to pre-made positions because it’s cheaper for them to mass produce, but that’s where we come in. We’ve been doing custom runs for years, so we know the ins and outs of making sure each custom block fits right, is insulated properly, and has the same reliability as our standard lines.
Wait, let’s address a common misconception: some folks think custom length terminal blocks are flimsy or lower quality because they’re not mass-produced. Nah, that’s not how it works. The modular design means each position is made from the same durable nylon or polycarbonate material as standard blocks, and the clip mechanism is identical—you won’t get a loose wire or a block that falls apart because it’s custom. The only difference is how many positions you put together, which is tailored to your exact needs. We do add a little QC check for every custom run to make sure the count is right, the gaps between positions are even, and that the screw terminals hold wires securely, so you never have to worry about a custom block failing because it was made to order.
Another thing to consider when going custom: do you need additional features with your length? Like, if you need a fuse holder integrated into one position, or a ground terminal at the start/end of the run, custom length lets us build that in without extra work. Someone reached out last year who was wiring a medical device (super strict on safety, by the way) and needed a 21-position block with a ground terminal on each end—standard blocks only had ground positions every 5, so a custom length let us add those extra grounds exactly where they needed to be, no cutting corners. That’s the big perk of custom: it’s not just adjusting length, it’s adjusting the whole setup to your project’s needs.
So how do you go about getting custom length terminal blocks? It’s simpler than you think. You don’t need a 10-page engineering drawing (unless you want one, obviously). Most of the time, you just tell us how many positions you need, any specific features you want (ground terminals, fuse positions, color coding, etc.), and the wire gauge you’re using. We can even help you adjust the length if you’re not 100% sure on the exact count—just tell us the space you have available, and we’ll size it right. We also work with small orders, so if you’re a DIYer with a tiny camper project, you don’t have to buy 100 custom blocks to get a 10-position one made. That’s a mistake a lot of people make—they think custom is only for big industrial orders, but it’s for every project.
Let me share a funny (well, funny now, not at the time) story from a few months back. A local electrician came in a panic on a Tuesday—he was finishing up a remodel on a small restaurant’s kitchen, and the terminal run for the exhaust fan’s wiring was exactly 19 positions, but all the standard 20-position blocks he’d brought were slightly too long. The kitchen’s wall for the wiring chase was cut to fit the 19-position length, so a 20-position would stick out and be a tripping hazard, plus it violated the restaurant’s electrical code (no exposed wiring in kitchen areas). We had a 19-position custom block ready in 2 days, and he got back to finish the job on time—saved him from a costly delay with the health inspector. That’s the kind of problem custom terminal blocks solve every single day.
Now, let’s get real—there are a couple of small caveats to keep in mind when ordering custom length. First, lead times: like I said, usually 3-7 days for standard runs, but if it’s a super specialized feature (like a custom color for the block to match your panel), it might be a week or two. Second, minimums: most suppliers, including us, have a small minimum, like 10 blocks, but that’s because custom production isn’t free—we have to set up the tooling for that specific count. But if you only need a few, some suppliers will work with you, just make sure to ask before you order. Third, compatibility: if you’re using terminal blocks with existing panels or wiring, make sure you know the wire gauge and screw type you need—custom length is useless if the block doesn’t fit your wires.
Wait, another question people ask: can you mix terminal block types for a custom run? Like, if you need some positions for 14-gauge wire and some for 12-gauge, can you make a custom length that has both? Yep, that’s totally doable. The modular system lets you swap out position sizes, so you can build a custom block that has exactly what you need, no more, no less. That’s a game-changer for projects that have multiple wire sizes in the same terminal run, which is super common in industrial and commercial wiring.
At the end of the day, custom length installation terminal blocks aren’t a luxury—they’re a solution for when standard blocks just don’t fit your project. We get why people ask, “Do I really need custom?” and the answer is: if standard blocks leave you with too many empty positions, take up too much space, or don’t fit your exact wire count, then yes, you do. No one wants to deal with messy, jumbled wiring in a control panel or a home setup, and custom blocks are the easiest way to get a clean, secure, code-compliant setup.
If you’re working on a project right now where the standard blocks aren’t cutting it—whether it’s a small camper build, an industrial control panel, or a commercial remodel—hit us up to chat about custom terminal lengths. We can walk you through the process, answer any questions, and make sure you get exactly what you need, no extra hassle. Don’t waste time forcing a square peg into a round hole with pre-made blocks—custom is the way to go for a smooth, stress-free project finish.
Rear Nut Connector References:
- Industrial Terminal Block Design Standards, National Electrical Manufacturers Association (NEMA), 2022
- Modular Terminal Block Applications Guide, International Electrotechnical Commission (IEC), 2021
- Installation Best Practices for Terminal Blocks, National Fire Protection Association (NFPA), 2023
Wonke Electric Co., Ltd.
Wonke Electric Co., Ltd. is one of the most professional installation terminal block manufacturers and suppliers in China. We’re offering high quality products with good price, please rest assured to wholesale bulk cheap installation terminal block made in China here and get free sample from our factory.
Address: No. 463, Guang’an Road, Dongmeng Industrial Zone, Wuniu, Yongjia County, Wenzhou City, Zhejiang Province, China 325103
E-mail: info@wonkedq.com
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