IDEAL Industries WT4-1 WireTwist® Wire Connector, Model WT4 Yellow, Box of 100

The WT4-1 is a twist-on wire connector (a wire nut) in IDEAL's WireTwist line, the yellow WT4 model, sold in a box of 100 pieces. Inside the shell is a fixed, square-wire spring that bites into the conductors as you twist it down, so no separate crimp or tape step is needed to make the splice.

No, and they aren't interchangeable. The WT4 WireTwist is a twist-on splice cap for joining conductors inside a box or fixture. The Leviton 15W33 industrial grade straight blade connector and the Pass & Seymour Turnlok 27W watertight connector are cord-end devices that mate with a plug to carry a flexible cord. If you're terminating a portable cord, you want one of those; if you're splicing building wire, you want the WT4.

No. The WT4-1 is a WireTwist twist-on wire connector - a spring-type insulated cap that twists onto stripped conductors inside a box, with a deep skirt to protect against flash-over. The Leviton 8319-C is a hospital grade NEMA 5-20R connector, a cord-mounted receptacle body used to terminate a flexible cord so a plug can be inserted into it. Both ship 100 to a box, but they do different jobs: use the WT4-1 for splicing conductors, and the 8319-C where a cord needs a female 5-20R termination.

The WT4-1 is a twist-on WireTwist wire connector for joining conductors in a box, so it will not terminate a flexible cord. For cord-end female terminations, the Leviton 8319-C is a hospital grade NEMA 5-20R connector and the Bryant 8269T is a hospital grade NEMA 5-15R connector; the Leviton 15W33 is an industrial grade straight blade connector rated 3-wire 2-pole, 125V 20A. Pick by the amperage and configuration of the circuit you are feeding.

The WT4-1 WireTwist shell is a tough UL 94V-2 flame-retardant housing rated to 105 C / 221 F, which addresses heat and flame, not water ingress. Where a watertight or weatherproof connection is the requirement, the Pass and Seymour Turnlok 27W Series is a 20A watertight connector rated NEMA 4X/6P, and the Bryant WPC Series is a weatherproof wiring connector fitting. Choose by whether you are splicing conductors in a protected box or making a connection exposed to weather.

The WT4 shell is rated to 105 degrees C (221 degrees F) and is a UL 94V-2 flame-retardant material, so it holds up in the temperatures seen inside fixture canopies, junction boxes and recessed housings where splices run warm.

Both are sold 100 to a pack. The IDEAL WT4-1 is the yellow WireTwist model, a twist-on wire connector using a fixed square-wire spring and a positive grip shell for fast installation. The Leviton ML2-C is an ML2 series midget connector for electrical wiring. If you are standardizing a truck stock on yellow twist-on nuts for the conductor combinations yellow covers, the WT4-1 is the one to carry.

The two are not alternatives to each other. The WT4-1 is a twist-on WireTwist wire connector for in-box splices. Hospital grade applies to the cord and receptacle devices on patient-care circuits: the Leviton 8319-C is a hospital grade NEMA 5-20R connector and the Bryant 8269T is a hospital grade NEMA 5-15R connector. A healthcare job commonly uses both - hospital grade devices at the cord ends and standard twist-on connectors for splices inside enclosures, subject to your facility's specification.

The extended skirt on the WT4 covers more of the stripped conductor and insulation, which guards against flash-over at the base of the splice. It also means less bare copper is left exposed if the splice gets pushed around when you fold the wires back into a crowded box.

The positive grip shell is built to be turned down by hand quickly, and the spring is a fixed square-wire type rather than a one-shot crimp, so a connector backed off a splice can be reinstalled as long as the shell and skirt aren't cracked or distorted. Buying in the 100-count box is what most crews do for this reason, since a few get retired on any rework job.