Not Your Average WireNut- What to Consider When Sizing a Terminal Block

Unlike a WireNut that just serves a function to keep wires bound together, Terminal Blocks actually carry current and can perform multiple functions - there’s much more to consider.  Let’s take a look at five attributes to consider when sizing your terminal block in most any application - they happen to be Function, Load, Wire Size, Voltage and Physical Size.

Function - What is the terminal block doing in your application?  Is it at feedthru, fuse, disconnect, sensor or ground block?  Does it require jumpers, fuse failure indication, disconnecting means, have multiple connections, or be of an unusual dimensional size?  These (as well as many more) are all important things to consider.

Load - How much current is downstream of the terminal block at peak times?  This is the number to be used as a baseline for sizing - you want a terminal block that will carry 30% more than the peak load to provide for a safety factor.

Wire Size - This is self explanatory but you have to make sure the terminal can accept the wires being brought to it!  Pay attention to welding wires and other types of non-standard wires, they can be quite different than a standard THWN wire.

Voltage - Most control cabinets are rated 600V - make sure your terminal block is too !  Voltage ratings apply to minimize the arcing and failure of base materials when subjected to high potentials.

Physical Size - You don't want to put 10lbs of potatoes in a 5lb bag!  - make sure the block is going to physically fit on the DIN Rail, in the housing, or in the control enclosure.  Make sure terminals can be accessed easily with no obstructions when using screwdrivers etc.

American Electrical, Inc (AEI) sells many types of DIN Rail mounted Terminal Blocks manufactured by Klemsan (  They are UL approved and used worldwide.  AEI stocks most versions and can ship today.  Most of all, the pricing is the most competitive in the WORLD - try us!  Call us at 804.379.2899 or visit us here on the web:

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