US & Metric Tool Size Guide: AWG, Inches, psi and More

Wire size: AWG, mm² and kcmil

AWG means American Wire Gauge. mm² is conductor cross-sectional area, not diameter. Ø mm means diameter in millimeters. The outside diameter of an insulated cable includes insulation and cannot be read directly from its AWG size. A larger AWG number generally means a smaller conductor; 1/0, 2/0, 3/0 and 4/0 are progressively larger sizes.

These are rounded AWG conductor-area references, not a die-selection chart or an electrical current-rating chart:

1 kcmil = 1 MCM ≈ 0.5067 mm². For example, 250 kcmil ≈ 126.7 mm² and 500 kcmil ≈ 253.4 mm². A 240 mm² rating does not automatically include 500 kcmil cable. Check both conductor area and the cutter’s maximum cable diameter.

Metric die labels such as 6, 10, 16, 25, 35 and 50 mm² are not exact equivalents of AWG die labels. Where a product lists both ranges, use the specified terminal, conductor construction and die schedule. Do not round a conductor into a tool’s capacity.

For Deutsch-style contacts, “contact size 12, 16 or 20” identifies the contact system; it is not the same as 12, 16 or 20 AWG wire. Match the exact contact part number, wire range, solid/stamped construction and tooling.

Connector pitch is center-to-center contact spacing, not wire size. 2.54 mm pitch = 0.100 in.; 2.50 mm pitch ≈ 0.0984 in. These are different dimensions. Lug stud-hole size is also separate from conductor size; an M8 marking does not mean 8 AWG.

Pipe & tubing: nominal size versus measured outside diameter

US plumbing sizes such as 1/2, 3/4 and 1 inch are commonly nominal system sizes. Do not multiply a nominal label by 25.4 to choose a metric press jaw. In contrast, ACR refrigeration tubing is commonly identified by actual outside diameter (OD). Confirm the tubing standard and fitting series.

This table describes US copper water tubing; it is not a universal pipe chart. A 15 mm, 16 mm or 22 mm jaw is not interchangeable with a nearby inch-size jaw merely because the measurements are close. Match the fitting system and specified jaw profile: V, TH, U, H, RF and SV are profile names, not unit conversions. DN is a nominal designation, not a measured diameter.

For PEX, match the nominal tubing size and connection method: copper crimp ring, stainless cinch clamp, cold expansion or stainless press sleeve. A matching size alone does not make these systems interchangeable.

Dimensions, weight, wire rope and strapping

Length × width × height describes the item or package identified in the specification. Tool weight and packaged shipping weight are different. “lb” in a weight row is pounds of mass; “lbf” in a force row is pounds-force.

Wire-rope diameter, sleeve size and swage-stud dimensions are separate specifications. A rounded metric equivalent does not approve a different rope or sleeve. Choose the matched rope, termination material, die and inspection method.

For strapping, compare both width and thickness. Nominal 1/2, 5/8 and 3/4 in. stock is often discussed alongside 13, 16 and 19 mm, but the dimensions are not exact equals. Check the tool’s stated tolerance, material and seal requirements.

Air pressure, force, torque and speed

These are conversion examples, not recommended operating settings. Use the selected tool’s rated supply pressure. Air consumption (L/min or CFM) is different from pressure; compare flow ratings only when their reference conditions match. Do not substitute a test pressure or hydraulic pressure for the required air supply.

“T” or “tons” can be ambiguous: US short ton-force and metric tonne-force differ. If the product does not specify which, request its force rating in kN or lbf. Crimping force and strap tension do not establish a finished assembly’s allowable working load.

Air connectors also require the correct thread and coupler. NPT and BSP are different thread systems; a matching fractional-inch label does not establish compatibility.

Voltage, frequency and temperature

Electrical units do not change between metric and US usage. Match the machine’s AC/DC supply, rated voltage range, frequency (Hz) and plug to the installation. A plug adapter does not change voltage or frequency. Do not assume a 200–230 V model covers every European supply, or that a “110 V” label guarantees every North American installation.

For temperatures, °F = (°C × 1.8) + 32. For example, 20 °C = 68 °F. Temperature limits must still refer to the specified component and operating conditions.

Send us the measurements that matter

Before ordering, send our product team the product/model link, selected option, country of use and a photo of your cable, terminal, fitting or strap marking. Include AWG or mm² for conductors; nominal size plus measured OD for tubing; rope/sleeve size for swaging; and width/thickness plus material for strapping. For powered machines, include the available air supply or electrical nameplate details.

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