Choosing electrical distribution switchgear protection comes down to matching the breaker to the circuit, not matching logos. The GE THED134150 and the Square D 12-718012-38 are both used three-pole breakers, but they protect very different loads. The practical payoff is avoiding two mistakes: buying a far heavier breaker than your panel needs, or trying to protect a large feed with a breaker that is too small. One of these units is built for much higher current than the other, and that difference drives the buying decision.
Quick verdict
Pick the GE THED134150 if your distribution board needs a three-pole molded case breaker and a moderate protection point. Pick the Square D 12-718012-38 if your switchgear needs a high-current three-pole breaker and your system is built around Square D equipment. The decision is about capacity and fit, not which brand is better.
At a glance
| Product | Condition | Price | Price bar | Current rating | Voltage | Poles |
| GE THED134150 150A 480V 3P Molded Case Circuit Breaker | Used | $460.00 | | 150A | 480V AC | 3 |
| Square D 12-718012-38 900A 600V 3 Pole Circuit Breaker | Used | $799.90 | | 900A | 600V | 3 |
Where each product wins
- GE THED134150 wins when you need a lower-priced, thermal-magnetic molded case breaker for a standard distribution panel and you do not need the huge current capacity of the Square D.
- Square D 12-718012-38 wins when you need the huge current capacity and the part number matches Square D MHL/MH-series switchgear.
GE THED134150 150A 480V 3P Molded Case Circuit Breaker
This GE breaker comes from the THED frame series and is specified as a three-pole molded case circuit breaker with a thermal-magnetic trip system and bolt-on mounting. That makes it a reasonable match for a 480V panelboard or motor control circuit where the circuit fits the rated current. It is a used tested unit, so you are not paying for a new component, and it costs less than the Square D, which makes it the more economical entry point for the smaller job. The limitation is that it cannot be stretched to a much larger feed: it is built for a moderate protection point, and if you try to use it where the system demands high current, you will undersize the protection. Match it to the actual load rather than hoping it will cover more.
Square D 12-718012-38 900A 600V 3 Pole Circuit Breaker
The Square D is the heavy-duty side of this pair. The part number is associated with Square D MHL/MH-series equipment, which points this breaker at large switchgear rather than a small panelboard. It is a preowned unit removed from a working environment, so it may show minor cosmetic wear from previous service. The reason to choose it is capacity: it is built for a much larger three-pole feed, and that is exactly what a 600V switchgear application needs if the bus is sized for high current. The trade-off is that it is not a general-purpose panel breaker; it is aimed at a specific class of Square D gear, and for a smaller 480V panel it is more breaker and more money than necessary. Match it to the bus that was designed for it.
Final choice by use case
Use the GE THED134150 for a standard panelboard or motor control circuit where the load is moderate and you want the lower-cost used breaker. Use the Square D 12-718012-38 for a high-current switchgear assembly where the part number is the right fit for the existing Square D equipment. If you are still deciding, start with the voltage and current rating of the existing bus. The breaker that matches that rating is the one to buy; the other one will be either undersized or wasteful.
