Minimum Bend Radius Chart [Calculate Wire & Cable Types Bending/NEC] (2024)

Calculating a copper or aluminum wire & cable’s minimum bend radius is the smallest allowed radius the cable is allowed to be bent around an object.During installation, cables are bent or flexed in various environmental conditions (Sometimes bent way too far!). Furthermore, wires and cables are often bent around a curve in conduits or underground ducts during installation, and bending radius is an input that installers need to know in order to get the cable and wire correctly pulled on their job.

Below you will find the best resources on bending radius for wire and cable, including an easy-to-use chart for figuring out your minimum bend radius per the NEC and ICEA, and a step-by-step calculator/guide for making this determination for your current or upcoming project.

Be sure to bookmark this page as a tab on your computer or smartphone by saving to favorites so you can reference back to use this handy bend radius tool.

Also, please remember there are some specialized bending radius calculations for different cables types per ICEA that we will cover further below such as DLO cable. Additionally, we sell electrical wire & cable all over the world so wherever you are working on calculating minimum bend radius and getting ready to buy your wire & cable, we can get you exactly what you need.

Call 1-888-651-9990 or message us for your pricing now.

How to Calculate Minimum Bend Radius of Cable and Wire? (Step-by-Step Formula & Calculator Tool per the NEC & ICEA)

  • 1st Step: First, determine your Cable Type (Types listed in Chart below)
  • 2nd Step: Second, is your cable single conductor or multi-conductor?
  • 3rd Step: Third, verify your Cables Voltage.
  • 4th Step: Fourth, is your Cable Shielded or Non-Shielded (Depending on Type)
  • 5th Step: Fifth, is your cable classified as a mining cable?
  • 6th Step: Sixth, does your Cable have Metallic Armor (MC)?
  • 7th Step: Seventh, cable type has been verified. Calculate Minimum Bend Radius using the formula in step 8.
  • 8th Step: Eighth, get Min Bending Radius by taking your wire & cable O.D. Outside Diameter x Cable Multiplier shown in Minimum Bending Radius Chart below. (Wire O.D. x Multiplier, depending on Cable Type)

Minimum Bend Radius = Wire & Cable Outside Diameter (O.D.) x Cable Multiplier by Wire & Cable Type

Examples Calculating Minimum Bend Radius using step by step guide above and 1XTech® Bending chart below.

Example 1: First, using the Bend Radius chart/tool below we see that a single conductor wire/cable without a shield, and less than 1000V has a minimum bending radius of 8x overall diameter.

Specifically, if we want to calculate the Minimum Bend Radius for a single conductor 500 MCM CU 600V THHN with an outside diameter of 0.902 Inches we would use the bending radius chart below paired with the step-by-step guide above to determine that single conductor THHN is less than 1000 volts, 1C, non-shielded, not a mining cable, not an MC Cable.

With this in mind, we see that the graph says we would use the table for NEC 300.34 after making our determination.

Minimum Bend Radius for 500 MCM THHN is the O.D. of Wire (0.902 Inches) x Cable Multiplier of 8X O.D. (1. NEC 300.34 / Graph below ) = 7.216 (MBR) Minimum Bending Radius

More MBR calculation examples are listed below the graph for your reference.

DLO CABLE MINIMUM BENDING RADIUS

First of all, during installation, DLO cables are bent or flexed according to the installation requirements. DLO cables are often bent around a curve in conduits, trays, or underground ducts. To prevent cable damage, cable standards associations, such as the Insulated Cable Engineers Association (ICEA), set requirements for minimum bend radius. Moreover, as per ICEA S-75-381, the applicable minimum bending radius for non-shielded power cables without metallic sheaths or armor are:

  • The DLO Cable Overall Diameter (O.D.) x 6 (Multiplying Factor Chart above))

COPPER THHN WIRE & CABLE MINIMUM BENDING RADIUS

First of all, during installation, THHN Wires and cables are bent or flexed according to the installation requirements. THHN/THWN-2 cables are often bent around a curve in conduits, trays, or underground ducts. Taking precaution, and to prevent cable damage, cable standards associations, such as the NEC, set requirements for minimum bending radius. Moreover, as per NEC 300.34, the applicable minimum bending radius for non-shielded power cables without metallic sheaths or armor are:

  • The Overall Diameter (O.D.) x 8 Multiplying Factor (Chart above)

COPPER XHHW-2 WIRE & CABLE MINIMUM BENDING RADIUS

First of all, during installation, Copper XHHW-2 Wires and cables are bent or flexed according to the installation requirements. XHHW-2 cables are often bent around a curve in conduits, trays, or underground ducts. Taking precaution, and to prevent cable damage, cable standards associations, such as the NEC, set requirements for minimum bending radius. Moreover, as per NEC 300.34, the applicable minimum bending radius for non-shielded power cables without metallic sheaths or armor are:

  • The Overall Diameter (O.D.) x 8 Multiplying Factor (Chart above)
Minimum Bend Radius Chart [Calculate Wire & Cable Types Bending/NEC] (2024)

FAQs

What is the minimum bend radius for NEC wire? ›

In the 2023 NEC®, Section 334.24 requires the radius of the curve of the inner edge of any bend in type NM or NMC cables to be at least five times the diameter of the cable. For flat cables, the major diameter dimension of the cable is used to determine the bending radius.

How to calculate minimum bending radius of cable? ›

The minimum bend radius is based on the diameter of the cable and the type of cable. The following formula is used: Minimum bend radius = cable outer diameter X cable multiplier Cable multipliers are determined by industry standards and vary depending on the cable type.

What is the code for cable bending radius? ›

The radius of the curve of the inner edge of any bend during or after installation shall not be less than five times the diameter of the cable. 2023 Code Language: 334.24 Bending Radius.

What is the minimum bend radius for a wire bundle? ›

Dimensions, layout and identification meet design requirements. Cables insulated with materials other than Kapton® shall not be bent less than six (6) outer diameters. The recommended long-term bend radius is ten (10) diameters.

What is the NEC 360 bend rule? ›

According to Sec. 358.26, the maximum degrees of bends permitted in one run is 360°. To reduce the stress and friction on conductor insulation, the total bends (including offsets) between pull points cannot exceed 360°.

What is the minimum bend radius rule? ›

We recommend a minimum bend radius of 1t for all sheet metal parts. Thus the smallest radius of any bend in a sheet should be at least equal to the thickness of the sheet. For example, if the thickness of the sheet is 1 mm, the minimum bend radius should be 1 mm.

What is the rule of thumb for wire bend radius? ›

According to the TIA/EIA-568 standards, the minimum bend radius for unshielded twisted pair (UTP) cable is 4 times the cable's diameter. Example: A typical Cat cable has a diameter of 0.25 inches. Using the formula, 0.25" x 4 = 1", the bend radius must be at least 1 inch.

What is the formula for bend radius? ›

The minimum bend radius formula is: L = A/360° x 2πr.

What is the minimum bend radius of a single wire? ›

Both the NEC (National Electrical Code) and C68. 10 (CSA cable standard these cables are built to) allow for 7 x cable OD min bend radius of multi-conductor cables and 12 X OD for single conductor cables.

What are the requirements of the NEC for bending conduit? ›

There shall not be more than the equivalent of four quarter bends (360 degrees total) between pull points, for example, conduit bodies and boxes.”

What is the minimum bend radius for 12 AWG wire? ›

Bend Radius: 5 x overall diameter installed / 8 x overall diameter during installation pull-in.

What is the bend radius of a flexible cable? ›

The minimum bend radius of an FPC cable is dependent on the thickness of the cable itself. Teledyne FLIR recommends a bend radius of 10X the cable thickness for reliable function.

What is the minimum bend radius for cat6 cable? ›

Minimum Bend Radius for a Category 5e or 6 Cable

The minimum bend radius for Category 6, 5, and 5e cable is four times the cable diameter, or approximately 1 inch. When cabling is bent beyond this specified radius, it can cause transmission failures.

What is the bending radius of conduit NEC? ›

Additionally, the NEC specifies minimum radius requirements for bends to prevent damage to the conduit and the enclosed wires during bending. The bend radius varies depending on the type and size of the conduit. For example, for 1/2-inch EMT, the minimum radius is 4 inches.

What is the minimum radius of a wire? ›

Minimum Bend Radius for Cable

According to the TIA/EIA-568 standards, the minimum bend radius for unshielded twisted pair (UTP) cable is 4 times the cable's diameter. Example: A typical Cat cable has a diameter of 0.25 inches. Using the formula, 0.25" x 4 = 1", the bend radius must be at least 1 inch.

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