Issue I've seen with using GE breaker on the a panel designed for Eaton BR or SD HOM is the the GE will practically require hammering them onto the bus of the Eaton BR style panel. The contacting points just don't make a clean contact onto the thicker BR bus as a result. Also removal practically need a pry bar to remove. Also if the BR style panel is full width bus stabs, the rejection device will prevent the GE breaker from seating fully onto the bus. (Seen it.)
How it works with breaker and panel mfrs is that the PANEL must be tested in its listing process for using specific breakers, and breakers must be listed by testing them in specific panels. For the most part, panel mfrs have zero incentive to list their panels with anything other than their own breakers. Breaker mfrs however can game the system a bit by testing their breakers in competitor’s panels, under a program called “Classified” breakers. Eaton has Classified breakers for use in many different brands of panels, Siemens as one or two, but that’s about it, the other mfrs steer clear of that.
In this case HAYWARD, who made the
panel, has apparently listed it for use with the BR, MP, QP or HOM breakers, so that’s what you can use. But since they did not SPECIFICALLY listed the GE breakers,
they cannot be used. One of the reasons why you rarely see the GE THQ breakers included in multi-listings such as this is for the reasons Fred B mentioned. They
appear to fit, but they actually were never made to and you have to force them on, which can lead to an improper connection to the bus. Lots of people do it and lots of hardware stores will tell you “they’re all the same” but it’s not true of GE THQ breakers and never has been.