Thomas & Betts RA18-250F Disconnects, 100 Pack

The RA18-250F is sized for 22-18 AWG stranded or solid wire, and the red nylon insulation is the standard colour code for that range. It will accept insulation up to 0.136 inch outside diameter, so heavier-jacketed appliance or fixture wire in that gauge still seats in the barrel.

It carries a 600V rating with a 105 degree C temperature rating, which covers 120V and 277V control and fixture wiring as well as low-voltage work. The nylon body is UL 94 V-2 for flammability, and the terminal is UL and CSA recognized.

ERG4001 is the recommended tool. Also listed as suitable are the WT145C, WT2000, WT112M and ERG4003. A standard insulated-terminal crimp die is what these need; the serrated barrel has a brazed seam, so the crimp is what carries the tensile load and a proper die matters.

The RA18-250F is a female 250 series disconnect sized for a .250 x .032 tab, so it mates with a male quick disconnect terminal of that tab size. The 3M MVU10-250DMX Scotchlok male disconnect terminal is a vinyl insulated male 250 disconnect sold in packs of 100, which pairs with a female 250 on the other end of the splice. Note the insulation difference: the RA18-250F uses insulated nylon, while the MVU10-250DMX is vinyl insulated.

No. Both are nylon insulated female disconnects for 22-18 AWG wire, but they terminate differently. The RA18-250F is a crimp disconnect with a brazed seam serrated barrel that you crimp onto a stripped conductor end using a tool such as the ERG4001. The 3M Scotchlok 951X is a female T-tap disconnect, designed to tap onto a run of wire rather than terminate a cut end. Use the 951X where you need to branch off an existing conductor, and the RA18-250F where you are terminating a wire end onto a .250 x .032 male tab.

They ship 100 to the inner pack and that 100 is also the order multiple, so quantities go up in hundreds rather than by the piece. The outer carton holds 500. Larger jobs that standardize on this terminal usually buy by the carton.

The barrel and contact are brass with an electro tin-plated finish, which is the normal combination for copper-wire terminations and resists corrosion better than bare steel. Stock thickness is 0.030 inch. They are also RoHS compliant.

The RA18-250F is a crimp-on female disconnect: you strip the wire end and crimp it into the barrel. A T-tap style such as the 3M Scotchlok 951X female T-tap, also rated 22-18 AWG, instead clamps onto a run of wire without cutting it, letting you branch off an existing circuit. Use the crimp version for wire ends and terminations; use the T-tap when you need to pick up power mid-run.

Use the 3M Scotchlok 951X female T-tap disconnect, which is a nylon insulated female disconnect for 22-18 AWG supplied in packs of 100 and intended to tap an existing conductor. The Thomas & Betts RA18-250F is a crimp-on female 250 series disconnect for a stripped wire end, so it requires cutting the run. Both cover the same 22-18 AWG wire range.

It is the main material difference between them. The Thomas & Betts RA18-250F uses insulated nylon rated UL 94 V-2 for flammability, with a 105 degree C temperature rating and 600V rating. The 3M MVU10-250DMX is a vinyl insulated male disconnect. Nylon sleeves generally hold up better to abrasion and handling during pull-through, while vinyl is softer; choose based on the environment and on whether you need the male or female half, since the RA18-250F is the female 250 and the MVU10-250DMX is the male.

Two dimensions are published for it: A at 0.91 inch and B at 0.29 inch. Useful when you are checking whether the terminal clears a crowded switch stack or fits inside a tight fixture canopy.