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iQ means Interoperability Quotient, and is our proprietary, patented technology which allows the use of identical components on all of the Concentric Devices' product lines. This allows all our products to act effectively and efficiently together. Learn more...

Just some of the benefits to terminal block design and implementation through iQ Technology are captive hardware, faster termination, greater design flexibility, increased safety, laser strip ID, and higher circuit density. Read more...


Concentric Devices terminal blocks are manufactured in the United States to the most demanding specifications. See the entire physical specifications list.

iQ technology produces the terminal block with the fastest installation and termination, safest operation and best circuit identification available. View the product.

Fully captive hardware and isolated electrical paths provide the safest and fastest way to shunt circuits for CT testing. A simple turn of a screw does it. No lost hardware, ever. View the product.

Interruptible Link provides circuit opening with captive hardware and isolated electrical paths. No loose hardware or potential contact with live buss bars. A simple turn of a screw does it. View the product.

For maximum design flexibility and circuit density, use din rail mounting.

For those customers who want to stick with traditional panel mounting, our panel-mount hardware fits all major patterns for screwmounting, making switching to our terminal blocks simple. Read more...

Never loose track of circuits again. Customize, laser etched ID strips identify your specific circuit. Find out more...


From a cost-saving, safety and design-flexibility vantage point, this new terminal block technology will revolutionize your approach to electrical connections.

Old vs. New Technology:

The terminal block industry is one that has been around, virtually unchanged for decades. Technology has advanced in the electrical industry, and Concentric Devices has joined its iQ technology with innovative designs to produce the next generation of electrical terminal blocks.

This technology provides totally captive hardware, dead front and finger safe isolation, maximum design flexibility, highest circuit density, fastest termination, positive circuit identification, easiest installation and quickest circuit testing after installation. The combination of these features provides the user with dramatic increases in productivity, safety and reliability.

Captive Hardware

  • Captive hardware ends problems with lost or loose hardware
  • Captive hardware provides for fastest termination of lugs
  • Totally captive hardware used for CT/shunting and i Link functional blocks

Old Technology – Slow Process with Potential for Problems

The existing terminal blocks require that you either remove a screw from a buss bar or position a nut over a stud in order to make a circuit termination.  Loose hardware can easily be dropped or lost during both the manufacturing and maintenance operations.  During troubleshooting, this is not only time consuming, but can lead to circuits being shorted by the dropped hardware.

New Technology – Totally Captive Hardware

With the Concentric Devices product lines, all hardware is captive.  No worry about lost time because you have dropped or are missing hardware.  No worry about hardware shorting circuits during maintenance.  There is no need to remove or replace hardware during the termination of circuits in the manufacturing process.  Insert the lug, engage the screw and on to the next circuit.  Time savings is better than 50%.  This applies to the terminal block, CT and i Link products.

DIN Rail Mounting

  • Provides for maximum design flexibility
  • Provides for maximum circuit density
  • Provides for quickest installation of terminal blocks
  • All products interchangeable within seconds

Old Technology � Panel Mounted Terminal Blocks

The conventional terminal blocks were panel mounted or screwed into the control panel. This required the designer to take the schematic diagram, determine the number of circuits, the functions required and the size of the terminal blocks to determine the layout. The layout then went into the machine shop for the tapping of holes in exact locations. Changes to the schematic frequently required a repeat of the process.

New Technology: Maximum Design Flexibility & Highest Density

By using Concentric Devices terminal blocks and the DIN rail means of attachment, the designer determines the number of circuits and has the machine shop weld the required length of DIN rail to the control panel.

Our "iQ Technology" allows each terminal block to have the same footprint. A 12 position block can be replaced by two 6 position blocks, with no space penalty. A 6 position CT block can be replaced by a 6 position i Link block. These changes can be made in seconds, with no need to retap holes in the machine shop. The integral CT and i Link blocks have the same footprint as the standard distribution block.

There is never a penalty for the panel mounting space allowances. Depending on the number of circuits, the space savings is between 20% and 50% over the panel mounted approach. More circuits in the same space and the lowest installed cost. However, for those who prefer, panel mounting adapters are available.

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Dead Front, Finger Safe

  • Completely isolated electrical paths
  • Totally safe during operation

Old Technology – Exposed Buss Bars and Contacts

Traditional terminal blocks have buss bars and contacts that are exposed when in live operation. This has the potential for shock, short circuits, bridged circuits, etc.

New Technology – Isolated Electrical Paths

All Concentric Devices products have completely isolated and enclosed electrical paths. No buss bars or contact points, which are live, can be contacted by personnel. Safety during operation and maintenance is assured.

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Color Coded Function

  • Immediate function determination
  • Speeds circuit troubleshooting and improves safety

Old Technology: Black was the Color

In the past, there was no color indication of a terminal block's function. Manufacturers had only one or two products with different functions. You had to determine the function by visual inspection of the exposed buss bars.

New Technology: Color Coded Identification

Today, Concentric Devices offers three distinct functional products, the distribution terminal block, the CT or shunting terminal and the i Link, circuit interrupter block. With all buss bars and hardware being isolated, we use bright colors so that the functions are immediately identifiable. Additionally, the yellow CT block and the silver i Link block are permanently labeled by laser.

This provides for speed in the panel layout, and safety in circuit maintenance, once installed.


Laser Circuit ID

  • Permanent identification eliminates poor circuit ID
  • Permanent identification speeds circuit testing and improves safety

Old Technology: Poor or Limited Circuit ID

In traditional terminal blocks, circuit identification was limited to small, hand-marked ID strips which were difficult to use, difficult to read and, often, quite fragile.

New Technology: Customizable, Laser Etched ID Strips

Concentric Devices will laser etch circuit identification strips, which snap into the top of every terminal block. Standard numbered circuit identifiers are supplied. Customized circuit identification strips are available.

The permanent, specific circuit identification increases the speed of termination during manufacturing and dramatically speeds circuit troubleshooting, with increased safety.