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Using & Choosing Wire Nuts

Any DIY home handyman who as undertaken any electrical work has used wire nuts (Figure 1). A wire nut is a device that aids in the connection of a group of electrical wires. It not only holds the joint secure, but provides insulation for the mechanical wire joint.

It should be noted that "wire nut" is a trademark of Ideal Industries, but like Kleenex, it has become the primary identification for the product.

Many manufacturer's make similar products under their own trade names and trademarks.

Assortment of different size wire connectors
Figure 1 - Assortment of wire connectors

To avoid problems, such as loose wire connectors causing intermittent power problems or even worse causing a fire, it is important that the proper size wire connector is used when joining wires.

Although many of the new wire connectors say that pre-twisting the wires is not necessary, in my opinion creating a solid mechanical joint, see Figure 2, will prevent wires from dislodging from the wire connectors at a later date, especially if multiple gauge wires and/or stranded and solid wires are being held by one connector.

Wire nuts on twisted wires
Figure 2 - Wire nuts on twisted wires
  • Using a wire connector that is to big will result in poor grip onthe wires.
  • Using a wire connector that is to small will prevent the twisted wires from entering the wire connector to a depth that provides proper holding power and insulation.

There are of course dozens of wire gauges and the combinations of wire gauge size connections that can be created are in the thousands.

But as most home handymen are working with normal house electrical circuits we will deal with the most likely gauges and connections that they will face.

Table 1 provides the basic wire nut/connector sizing considerations.

Table 1 - Wire Nut/Connector Sizes

Color

Wire Combinations

Gauges

Minimum

Maximum

Grey

  

#22 to #16

2 - #22

2 - #16

Blue

  

#22 to #14

2 - #22

3 - #16

Orange

  

#22 to #14

1 - #18 & 1 - #20

4 - #16 & 1 - #20

Yellow

  

#18 to #12

2 - #18

4 - #14 & 1 - #18

Red

  

#18 to #10

2 - #14

2 - #10 & 2 - #12

For the home handyman the wire connectors that will do 99.5% of the tasks around the home are red and yellow.

However, having a kit of assorted sized wire nuts means that you will be able to connect almost any combination of wires.

Note: Some wire connectors have a wire spring inside them that grip the wires, others do not. You should always use the wire connectors that have the wire spring inside.

Selection of wire nuts.

Wire nuts are also available for aluminum wires, weatherproof, underground and high temperatures.

Additional information on terminating wires

Additional information on wire gauges.