The decision: match the coil voltage to your control circuit
When you need a definite-purpose contactor for a 40-amp motor load, the core decision isn't really about the contact rating - both of these Shopcorp contactors handle 40A inductive/motor loads and 50A resistive/incandescent loads. The choice comes down to the coil voltage that your control system can supply. Get that wrong and the contactor won't close, even if everything else fits.
You also don't have a price-based tiebreaker here: both are listed at USD 22.99. So the useful comparison is the coil voltage and what it means for your specific set up.
Quick verdict
If your control circuit runs on 110/120VAC - typical for line-voltage HVAC controls - go with the Shopcorp AC Contactor 40 Amp 50 RES 2 Pole 110/120VAC Coil. If your control system uses 24VAC, common with thermostats and low-voltage controls, the 24VAC Coil version is the right pick. Both offer the same contact ratings, same 2-pole normally-open configuration, and both carry UL listed wording in the product title.
At a glance
| Model | Coil Voltage | Current Rating | Listed Price |
|---|---|---|---|
| AC Contactor 40 Amp 50 RES 2 Pole 110/120VAC Coil | 110/120 V | 40 A | USD 22.99 |
| AC Contactor 40 Amp 50 RES 2 Pole 24VAC Coil | 24 V | 40 A | USD 22.99 |
Where each product wins
110/120VAC Coil version wins when you have line-voltage controls already in place. It's intended to be energized directly by a 110/120V circuit, which is common in residential and commercial HVAC equipment where no low-voltage transformer is needed.
24VAC Coil version wins when your control transformer or thermostat provides 24VAC. This is the standard for many HVAC systems, especially those using low-voltage thermostats or building automation controllers.
Product notes
AC Contactor 40 Amp 50 RES 2 Pole 110/120VAC Coil - Definite Purpose UL Listed
This 2-pole contactor is built for HVAC, refrigeration, lighting, and heat pump applications. It's rated AC-1 for resistive loads like incandescent lamps and heaters, and AC-3 for inductive loads like compressors and fans. That means it can carry 40A on motor loads and 50A on resistive loads. The coil is designed for a 110/120VAC supply, so if your control panel or line-voltage circuit operates in that range, this is the direct match. It's a new unit, panel mount, with a country of origin listed as China. The limitation to keep in mind: don't try to drive it with a 24VAC control signal - the coil is not rated for that voltage.
AC Contactor 40 Amp 50 RES 2 Pole 24VAC Coil - Definite Purpose UL Listed
This is the same 40A, 2-pole contactor package, but with a coil designed for 24VAC. It suits those low-voltage control setups, which are very common in HVAC thermostats and relay logic. The product description highlights the same AC-1 and AC-3 ratings for resistive and motor loads, so you get the same 40A/50A capabilities. It's listed as a new, panel-mount unit with a country of origin of the United States. The catch is inverse: if your control circuit provides 110/120VAC, this 24V coil is not the right match. Use this version only where 24VAC is available.
Final choice by use case
- For 110/120V line-voltage controls: Choose the AC Contactor 40 Amp 50 RES 2 Pole 110/120VAC Coil. It matches that supply voltage directly.
- For 24V thermostat or low-voltage controls: Choose the AC Contactor 40 Amp 50 RES 2 Pole 24VAC Coil. It's built for that lower coil voltage.
- For equal load capacity: Both handle 40A motor loads and 50A resistive loads, so neither has an edge in current handling.
- For same price: The listed price is identical, so your buying decision should hinge on coil voltage compatibility rather than cost.
