When the main power drops, an automatic transfer switch decides whether your lights stay on. These four automatic backup transfer switches are built around the same job, but they do not all hand off power the same way or cover the same circuits.
Quick take
All four are automatic transfer switches, but they split into two practical groups: models aimed at a generator or inverter path and models built for heavier changeover duty. Use the comparison table below, then match pole count and control voltage to your existing setup.
Listed prices and standout specs
The listed prices run from $29.99 to $53.81, with the Dual Power Selector at the low end and the 3P 100A transfer switch at the high end.
| Product | Listed price | Price bar | Standout detail |
|---|---|---|---|
| Double Power Switch, Dual Power Automatic Transfer Switch | USD 43.96 | 63A, about 2s conversion | |
| Automatic Transfer Switch, 63A 110V/220V Dual Power Selector for Generator L1 | USD 29.99 | 63A, adjustable L1/L2 priority and delays | |
| Automatic Transfer Switch 3P 100A Transfer Switch Dual-Power Transfer Switch | USD 53.81 | 100A, under 0.1s conversion | |
| Dual Power Automatic Transfer Switch Grid to Alternator 2P 100A 220V AC 50/60Hz | USD 32.99 | 100A, 2P, 220V AC control |
Decision matrix
- For a generator or backup inverter setup where you want to control which source is primary, the Dual Power Selector for Generator L1 gives you adjustable transfer behavior.
- For a grid-to-alternator changeover, the Dual Power Automatic Transfer Switch Grid to Alternator is the direct match.
- For a speed-focused handoff between primary and backup power, the rapid-changeover model is the pick.
- For a general dual-power switch in a fixed location, the Double Power Switch's screw-mounted body suits a home, office, or public building install.
Product notes
Double Power Switch, Dual Power Automatic Transfer Switch
Rated at 63A and 110V AC, this dual-power switch is positioned for homes, high-rise buildings, shopping malls, factories, and office buildings, including locations where fire protection is required. Its plastic and red-copper construction is formed through die-casting, and the screw-mount body makes it a fixed-location option. The transfer time is about 2 seconds, so it is not the fast-changeover pick. For a straightforward dual-power switch that covers both everyday and public building use, this model pairs a broad application list with a simple screw-mount install.
Automatic Transfer Switch, 63A 110V/220V Dual Power Selector for Generator L1
The Elecbee Dual Power Selector is built for generator and backup-inverter use. You can adjust the overcurrent value, startup delay, transfer delay, and priority phase through its buttons, then hold SET to save the parameters. The housing uses PA6 material with a V-0 flame retardant rating, which adds insulation and heat resistance. The trade-off is condition: it is new open box, so the packaging or seals may be different from a sealed unit. For a tunable automatic transfer switch, it offers hands-on control over when the switch leaves the primary source.
Automatic Transfer Switch 3P 100A
This is a three-pole automatic transfer switch with a conversion time under 0.1 seconds, the fastest in the group. The body is cold-rolled sheet with a plastic-spraying process, and the insulation voltage is 690V AC. It is wall-mounted, so it suits a fixed installation. The trade-off is applicability: a three-pole switch is not the match for a two-pole changeover path. It also sits at the top of the price spread among these four, which is worth weighing if you only need a smaller two-pole setup.
Dual Power Automatic Transfer Switch Grid to Alternator (2P 100A)
This GraceGalaxy switch is a two-pole 100A unit with a 220V AC control voltage and CE certification. The new-condition status and 50/60Hz operating range keep it aligned with the other automatic switches here. It is designed for grid-to-alternator changeover, and the packing list includes the 2P 100A 220V AC transfer switch. Because the control path is specified at AC220V, it is not the flexible 110V/220V option. If your backup source is an alternator and you need a two-pole transfer switch on that 220V AC path, this model lines up with the application directly.
Final recommendation by use case
Match the switch to the poles and amperage of your existing power path. For a generator or inverter backup circuit that should favor one source, the Dual Power Selector for Generator L1 is the control-focused pick. For a grid-to-alternator system, the Grid to Alternator model is the direct match. For a speed-focused installation, the rapid-changeover Automatic Transfer Switch fits. And for a fixed-location install, the Double Power Switch covers homes and public buildings without a complex setup.
