FAQ - Easyjoint Electric Co., Ltd.

1. What Is a Crimp Terminal?

A crimp terminal primarily relies on mechanical deformation and contact pressure to establish a reliable electrical and mechanical connection.

Unlike a solder terminal, which relies on molten solder to form the connection after cooling, a crimp terminal creates the connection through controlled mechanical compression of the terminal and conductor.

2. Basic Knowledge for Selecting Crimp Terminals

Cable Size: Conductor Cross-Sectional Area (mm²) and AWG

Crimp Terminal Selection Quick Reference Guide - Beginner-Friendly

Understand These Three Terms First

① Terminal Size

This refers to the size of wire that the terminal is designed to accommodate. It is normally specified in mm² (square millimeters).

Generally, the larger the number, the larger the terminal and the larger the conductor it can accommodate.

② Conductor Cross-Sectional Area

This indicates the size of the wire itself. When selecting a terminal, find the range that matches your conductor cross-sectional area.

③ AWG

AWG stands for American Wire Gauge, a standardized wire-sizing system used in the United States.

Important: The smaller the AWG number, the larger the wire. For example, a 2 AWG wire is much larger than a 10 AWG wire.

Terminal Size / Wire Size / AWG Reference

Terminal Size (mm²)	Compatible Wire Size (mm²)	Approx. AWG	Typical Application
0.5	0.1–0.5	22–16	Smallest size; signal wires and fine electronic wires
1.5	1.5–2.5	18–14	Small terminals; lighting and low-power appliances
2.5	2.5–4	14–12	Common size; sockets and switch wiring
4	4–6	14–10	Small-to-medium terminals; moderately powered equipment
6	6–10	12–8	Medium size; motors and power wiring
10	10–16	10–6	Medium-to-large size; high-current equipment
16	16–25	8–4	Large size; main circuits in distribution cabinets
25	25–35	6–4	Large size; high-current power distribution
35	35–50	4–2	Extra-large size; main power cables
50	50–70	1/0	Very large size; heavy-duty main cables
70	70–95	2/0	Extra-large size; high-current main cables
95	95–120	3/0	Heavy-duty size; main incoming cables
120	120–150	250 MCM	Extra-heavy-duty; large cross-section cables
150	150–185	300 MCM	Large industrial power cables
180	185–240	400 MCM	Extra-large cables; major engineering projects
240	240–300	500 MCM	Very large cables; power plants and heavy industry
325	300–400	600 MCM	Maximum-size range; very large conductors

Selection Tip

First, measure or identify the conductor size → find the corresponding wire-size range in the table → select the appropriate terminal.

Do not select a terminal that is too large, as it may not be crimped tightly enough. Do not select one that is too small, as the conductor may not fit properly.

3. Stud Size and Clearance Hole Size

Stud Size & Clearance Hole Size Chart

Know These Three Things First

① Stud Size

The stud size refers to the diameter of the bolt or screw shank.

Sizes such as #2, #4, and #10 are American screw sizes, while sizes such as 1/4" and 3/8" are fractional-inch bolt sizes.

A larger number or fractional size generally indicates a larger stud diameter.

② Clearance Hole

The clearance hole is the hole through which the bolt or stud passes.

The hole should normally be slightly larger than the stud diameter rather than exactly the same size.

③ How to Read the Chart

Each row shows a matched pair. Find the required stud size on the left, and the recommended clearance-hole size is shown alongside it.

Stud Size	Stud Dia. (mm)	Stud Dia. (inch)	Hole Dia. (mm)	Hole Dia. (inch)	Quick Note
#2	2	0.079	2.2	0.087	Smallest size; mini signal terminals
#3	2.5	0.098	2.7	0.106	Extra-small terminals
#4	3	0.118	3.2	0.126	Small terminals; low-current wiring
#6	3.5	0.138	3.7	0.146	Small-to-medium terminals
#8	4	0.157	4.3	0.169	Common small terminal size
#10	5	0.197	5.3	0.209	Medium terminal size
1/4"	6	0.236	6.4	0.252	General-purpose standard size
5/16"	8	0.315	8.4	0.331	Medium-to-large terminal
3/8"	10	0.394	10.5	0.413	Large terminal size
7/16"	11	0.433	11.5	0.453	Extra-large terminal
1/2"	12	0.472	13	0.512	Large size; common in power distribution
9/16"	14	0.551	15	0.591	Large-to-extra-large
5/8"	16	0.630	17	0.669	Heavy-duty terminal
11/16"	18	0.709	19	0.748	Extra-large, heavy-duty
3/4"	20	0.787	21	0.827	Very large terminal
7/8"	22	0.866	23	0.906	Jumbo terminal
15/16"	24	0.945	25	0.984	Largest size; high-current terminals

Pro Tip

Choose the required stud size first, then select the corresponding clearance-hole size.

If the hole is too small, the bolt will not fit. If it is too large, the connection may become loose.

4. Terminal Selection

No.	Terminal Type	Design Features	Connection Method	Typical Applications	Selection Notes
1	Ring Terminal	Ring-shaped end with a center hole	Installed over a screw or stud and secured by tightening	High-reliability applications, industrial equipment, automotive circuits	Helps prevent pull-out or shifting under wire tension; suitable for large wire sizes and applications where vibration resistance is important
2	Spade / Fork Terminal	Fork-shaped end with two prongs	Slides under the screw head without completely removing the screw	Household appliances, test equipment, frequent connection/disconnection	Approximately 22–10 AWG; fast installation and removal, but may come loose if the screw loosens
3	Blade Terminal / Quick-Disconnect Tab	Flat blade with pressed serrations	Mates with blade receptacles through push-on or pressure-fit connection	Timers, motors, valves, relays, mechanical switches, wiring harnesses	Serrations increase friction and improve retention; suitable where installation space is limited; available in insulated and non-insulated versions
4	Hook Terminal	Hook-shaped end	Hooked around a screw or stud; requires clearance around the screw	Applications where the screw cannot be completely removed but sufficient space is available	Easy to install and helps prevent pull-out; generally not recommended for harsh environments or high-conductivity requirements
5	Pin Terminal	Pin-shaped end	Inserted into a round mating hole and secured by pressure	High-density connections and low-current signal transmission, including electronics and PCBs	Suitable when the mating position is a round hole
6	Positive-Lock Terminal	Locking latch / snap-fit design	Inserted into a receptacle or connector	Quick-connect applications	Automatically locks after insertion, providing retention and protection against accidental disconnection
7	Flanged Spade Terminal	Fork-shaped end with raised flanges	Slides under the screw head and is secured by tightening	Applications requiring additional anti-slide-out protection	The flange helps prevent the terminal from sliding out of the mating position
8	Recessed Blade Terminal	Blade-shaped end with a recess/notch at the tip	Secured by a screw or plate-type mounting method	Applications where multiple terminals are mounted on the same screw	The recessed design makes stacking multiple terminals on one screw more convenient
9	Copper Tube Terminal	Manufactured from high-purity copper tube	Crimped onto the conductor	High-current applications	Provides stable and consistent performance; suitable for high-ampacity applications
10	Continuous Terminal Strip (Machine-Applied)	Multiple terminals connected by a carrier strip	Automatically fed and crimped by semi-automatic or fully automatic machines	Mass termination for electronics, PCBs and automated control systems	Improves production efficiency and crimping consistency
11	Butt Connector / Splice	Tubular splice	Wire-to-wire connection	Joining or extending wires	Provides a more secure and stable connection than simply twisting wires together
12	Male/Female Connector (Quick-Disconnect)	Male and female plug-in pair; semi-insulated or fully insulated	Push-on plug-in connection	Low-current applications requiring frequent mating and unmating	H65 brass or phosphor bronze can be used; phosphor bronze is suitable for frequent mating cycles. A copper sleeve can be added to the barrel when higher pull-out force is required
13	Wire Ferrule (Cord End Terminal)	Tubular sleeve	Wire is inserted into the ferrule and crimped before installation	Stranded-wire termination where working space is limited	Prevents strand fan-out and loose connections; useful when other terminal types cannot fit the installation position
14	Copper Cable Lug	Copper cable lug designed for conductor termination	Crimped onto the conductor	Power distribution and high-current electrical connections	Select according to conductor size, stud size, material, plating and application requirements

5. Selecting the Right Copper Material and Plating Process

Common Terminal Insulation Options

Uninsulated Terminal
PVC Insulated Terminal
Nylon Insulated Terminal
Heat-Shrink Insulated Terminal

Uninsulated Terminals

The metal portion is completely exposed and is typically made from copper or tinned copper.

Because the metal is exposed, it may be more susceptible to environmental corrosion.

Temperature resistance:
There is no insulation layer. Temperature resistance mainly depends on the metal and surface plating.

Mechanical protection:
Limited mechanical protection; the exposed metal can be damaged by external forces.

Typical applications:
Suitable for applications requiring high electrical conductivity where environmental conditions are relatively controlled.

PVC-Insulated Terminals

The metal portion is covered by a colored PVC insulation layer.

Color coding, such as red, blue and yellow, helps identify terminal sizes and provides protection against moisture and corrosion.

Typical applications:
Applications requiring insulation protection, moisture resistance and corrosion protection.

Nylon-Insulated Terminals

The metal portion is covered by a colored nylon insulation layer.

Nylon generally provides higher mechanical strength, better impact resistance and greater toughness than PVC.

Typical applications:
High-temperature, high-humidity and corrosive environments, as well as applications requiring improved mechanical strength.

Heat-Shrink Terminals

The metal portion is covered by a colored heat-shrink insulation layer.

After heating, the insulation shrinks tightly around the connection, providing improved sealing and environmental protection.

Typical applications:
High-temperature, waterproof and demanding outdoor environments.

6. Common Mistakes When Selecting Cable Terminals

Inspection Window

The size and design of the inspection window can affect terminal selection.

For applications involving continuous high current, CKS copper tube terminal series can be considered, such as:

SC - Standard Copper Cable Lug
SCK - Square Inspection-Window Copper Cable Lug
DSC - Copper Cable Lug Without Inspection Window

The primary purpose of the inspection window is to make it easier to check whether the conductor has been fully inserted and properly positioned before crimping. It is not necessarily a required feature for every application.

Many customers can successfully use SC terminals with a semi-circular inspection window because the operating current does not exceed the terminal's maximum rated current.

Consider the Actual Application Current

Electrical current can generally be divided into:

Continuous high current
Short-duration or transient high current

When selecting a copper cable lug, the customer should provide information about the actual application and operating conditions.

Terminal selection should not be based solely on cost reduction. An inappropriate copper tube or terminal size may result in an unreliable connection.

Even when a terminal is used within its nominal current rating, that does not automatically mean the terminal is suitable for every application.

The nature of the current, duration of the load, conductor size, installation environment and actual application conditions should also be considered.