A Complete Guide to Selecting Ideal Wire Nuts
A wire nut, also known as a twist-on wire connector, is an electrical connector used to fasten two or more low-voltage (i.e., not more than 600 volts) electrical conductors together. They are widely used in North America for making electrical connections. A wire nut looks like a colorful cup made of plastic.
This guide will help you select an ideal wire nut based on type, color, ampacity, and the application.
Wire nuts serve two main goals. First of all, they hold electrical connections together. Second, they cover the exposed metal. Here are some of the most common applications of wire nuts:
: Wire nuts are often used for connecting wires inside junction boxes, outlets, switches, and light fixtures for residential and commercial indoor electrical systems.
: Wire nuts can be used for their ease of installation and removal during electrical testing or when making temporary connections.
: Wire nuts are commonly used for splicing wires together in a junction box.
: Wire nuts can be used in low-voltage circuits like doorbell wiring or thermostat wiring.
: When adding new fixtures or changing existing electrical setups, wire nuts are often used to connect the new wiring to the existing system.
Wire nuts are not a great connector option for high-voltage applications, permanent outdoor applications, specialized circuits, and applications with permanent movements. If not installed safely, wire nuts can melt and lead to dangerous overheating of electrical cables.
Wire nuts, or twist-on wire connectors, work based on a simple principle of mechanical and frictional grip on the wires they're meant to connect. Here is the step-by-step guide to how you use a wire nut:
: Before you use a wire nut, you need to strip the insulation from the ends of the wires you want to connect, revealing the bare metal conductors.
: Hold the stripped ends of the wires together so they are aligned evenly.
: Place the wire nut over the aligned wire ends and rotate twist it clockwise. As you twist, the internal threads of the wire nut will grip the cables and pull them together. Ensure no bare wire is exposed beneath the wire nut and the connection is tight. Sometimes, for added security, electricians may also pre-twist the wires together before applying the wire nut.
: Give a gentle tug on each wire to ensure it's securely held by the wire nut and won't come loose.
These are the most common type used in residential wiring. They are typically color-coded to help users select the right size for their connecting wire combination. The name twist-on comes from the fact that they should be twisted to make a connection. They are used with light switches, ceiling fans, outlets,HVAC, and many other applications.
These have "wings" or protrusions on their sides, making them easier to twist and provide a better grip, especially when wearing gloves. Other than that, they are a variation of a standard wire nut.
Instead of the typical round design, these have a square or rectangular shape, which can provide a better grip in some situations. This works great if you're wearing gloves or the wire nut is in a hard-to-reach place. Other than that, these wire nuts are similar to standard round ones.
These have an extended skirt to provide extra insulation, especially when exposed wire ends are possible. The longer skirt ensures a better cover and minimizes the chances of flash-over between connectors.
For applications that might be exposed to moisture, these wire nuts contain a gel or silicone sealant to protect the connection from water. They are often used in outdoor or underground connections.
With push-in wire nuts, you simply push the stripped end of the wire into the connector instead of twisting them together. They have a transparent body, allowing you to see the wire inside, ensuring a proper connection. Push-in wire nuts are used because of their convenience, but some electricians prefer traditional twist-on connectors. The reason for this is that push-in connectors don't accommodate a wide range of wire gauges and are not reusable.
These are similar to standard wire nuts but have a flexible spring instead of a coiled metal insert. This design can provide a more robust grip on the wires.
Specifically designed for grounding applications, these connectors have a hole through which a grounding wire can pass straight through while other wires are twisted inside. Some grounding wire nuts come with an integrated hole or port where a single, uncut ground wire can pass through and extend out of the connector. This can be especially useful when a ground wire needs to be attached to a device.
Designed for applications where elevated temperatures are expected, such as in light fixtures. They can withstand higher temperatures without melting or degrading. High temp wire nuts are made either of ceramic or thermoplastic materials designed to withstand high temperatures. High-temperature wire nuts are used in lighting fixtures and heaters.
For extremely high temperatures, you might come across entirely ceramic connectors. These can withstand much higher temperatures than plastic or thermoplastic connectors but are also more brittle and must be handled carefully. They do not have a metal coil inside. Instead, their design relies on the ceramic material's properties to maintain a tight connection. Ceramic wire nuts can handle temperatures much higher than their thermoplastic counterparts, often upwards of 650°C (1200°F) or more.
Older homes might have aluminum wiring. These special wire nuts are designed to safely connect aluminum to copper wires, as direct connections can lead to corrosion and overheating. Inside these wire nuts, there's typically an anti-oxidant compound to prevent oxidation of the aluminum wire. This compound ensures a secure and corrosion-resistant connection.
Manufacturers use color coding to help users identify the correct type of wire for their respective applications. Though colors of wire nuts can vary according to the manufacturer, they are usually quite consistent. Here are the common color codes of wire nuts:
: Used for small wire combinations, such as two 22 AWG wires.
: Common for small to medium wire combinations, like three 16 AWG or three 18 AWG wires.
: Often used for connecting two 18 AWG wires. Typical for light or fan fixtures.
: Frequently used for two or three 12 AWG or 14 AWG wires.
: Suitable for larger wire combinations, such as two 10 AWG with one 12 AWG wire or three 10 AWG wires. Also suitable for 3 to 4 14 AWG or 12 AWG wires.
or
Brown: These are often used for intermediate wire sizes, such as two 12 AWG with one 14 AWG wire, as well as 2 to 3 14 AWG or 12 AWG wires. In this color, wire nuts are usually a twister type.
: Used for grounding applications only.
: Aluminum-to-copper wire nuts.
The size chart below indicates the minimum and the maximum size and numbers of wire that go with the wire nut of a particular color.
To select a wire nut, determine the type (solid or stranded) and size (gauge) of the wires you are connecting. Next, count how many wires you'll be connecting together.
Wire nut packaging typically provides a chart or list of wire combinations the connector can safely accommodate. The color code of the wire nut will help you understand which wire you need. Finally, consider the environment where the wire nut will be installed. For example, if the conditions are damp, you will need a waterproof wire nut. Also, you should consider which shape of the wire nut is the most convenient for you in terms of installation.
NNC sells different
wire nuts
for all potential purposes.
In metal stamping, achieving precise and efficient results is paramount. Among the crucial elements that contribute to this success is the careful selection of die springs. These seemingly humble components play a vital role in maintaining optimal performance, prolonging tool life, and ensuring consistent quality in metal stamping operations.
But how does one navigate the myriad options available and make the right die spring choices? Read on.
What is a die spring? Simply put, it’s a spring that holds materials in place during manufacturing processes. Die springs are designed to perform under high compression force and apply a specific amount of pressure to compression points on the materials they hold in place. They are also designed to withstand extremely high and low temperatures.
Some common applications of die springs include metal stamping, custom machining, and plastic injection molding.
There are a variety of die spring options available, and selecting the right ones will depend on your use case. Some of the most important considerations for die spring selection are required functionality, material, shape, and end style.
There are two main types of die springs: mechanical and nitrogen gas springs. Mechanical springs are helically coiled metal springs that work by storing and applying compressive force mechanically by expanding and contracting. Mechanical die springs are the traditional type of spring used in dies and are similar in appearance to springs used broadly in other applications.
Nitrogen gas die springs exert force using compressed nitrogen gas, which is contained in a cylinder and compressed by a piston. Such designs can produce greater force than standard mechanical die springs and are also engineered with more safety features.
When deciding between mechanical and nitrogen gas springs, it’s crucial to consider:
— Mechanical die springs will have a significantly lower upfront cost than nitrogen springs. But remember, with lower/higher cost often comes lower/higher quality.
— Nitrogen gas springs will last much longer than mechanical springs, reducing the overall cost of the component over its lifetime
— Nitrogen die springs are capable of exerting more force than mechanical options, which means that you may need more mechanical springs to obtain the same result.
— Mechanical die springs are just springs; for extreme conditions or complex dies, nitrogen gas die springs are the only option that offers safety features.
Some of the most common die spring materials include oil-tempered steel, steel alloys, chrome alloys, chrome silicon, and chrome vanadium. Chrome layers on alloys improve corrosion resistance. Chrome silicon and chrome vanadium are less common due to their increased cost, but they are much stronger than other die spring materials.
Mechanical die springs are typically coated or marked with colored vinyl that is color-coded to indicate the working load of the die springs. The working load required will correspond with the appropriate die material. Stronger materials such as chrome silicon are called for in applications requiring fewer stress points, greater accuracy, or high temperatures.
While the shape of mechanical die springs themselves is helical, there are three different wire shapes out of which die springs can be made: rectangular, round, and oval.
Rectangular wire die springs are compliant with ISO Standard 10243 and are available in inch and metric sizes. Rectangular wire produces more force than round or oval wire, and therefore, rectangular wire die springs are available with higher load capacity options. However, because the wire is rectangular, this results in the spring twisting as it moves, resulting in stress that can lead, eventually, to the failure of the spring.
Round wire die springs are commonly used in the US and are generally smaller in size and used for lighter compression applications. Round wire will withstand stress well but cannot produce the same force as rectangular wire springs of the same dimensions.
Oval wire die springs are standard in the US. Their design optimizes for the perfect compromise between the stress resistance of round wire and the load capacity of rectangular wire. Moeller Precision Tools now carries new and improved oval die springs, our R series, which include four load capacity options and are completely interchangeable with Raymond and other competing brands.
Mechanical die springs can have either open or closed ends. Because mechanical springs are helical, their ends can terminate in one of two ways: with a complete helix, leaving an end of the spring coil unattached, or with an incomplete helix, attached to the previous helix and connecting the coil end back to the spring. Open ends result in an uneven surface unless they are grounded; depending on the application, this may or may not affect the performance of your die. Closed-ended die springs will have even end surfaces, but because the final helices are incomplete, the compression of the spring may be altered or reduced.
Moeller Precision Tool carries an extensive variety of mechanical and nitrogen gas die springs to meet the needs of your application, including load options not carried by our competition. Learn more about our reliable, high-quality die springs, check out our die spring offerings, or contact us today.