I'm considering a Type 2 SPD install in my garage sub-panel the which provides the majority of feeds inside my house. The main panel is already protected by a Siemens FS140 SPD, but since the sub-panel is approximately ~75 ft away, I feel I need some additional layered protection. The sub-panel breaker in the main is 100A. There are a handful of other important 240V (pool equipment, AC compressors, etc) as well as a few 120V feeds for inside/outside the house.

Garage sub-panel is an in-frame, dry-walled CH. I'm considering the Eaton CHN230SUR or CHN250SUR because they are on-breaker and very easy to add to my panel. I'm looking at these over the CHSP2ULTRA (don't want to tear up the wall) and CHNSURGE (less protection and no warranty). Both the 230 and 250 appear to have the same protection per the Eaton marketing material.

Question: Which would be the more appropriate for my situation, the CHN230SUR (30 AMP breaker) or CHN250SUR (50A breaker)? My Siemens SF140 calls for a 20A breaker, the CHSPSULTRA calls for a 50A breaker, but these apparently are very similar in performance. The breaker size aspect confuses me. Any help appreciated. Link below:

Eaton SPD Brochure


  • Drywall repair is easy. Drywall repair in a garage should be even easier, as standards of perfection and paint matching are generally lower than the living room, etc. Given that other things might need to be added at some point, perfectly reasonable to cut out the drywall above and/or below the panel and "finish" it by screwing on nice neat plywood panels that can be unscrewed when access is needed again.
    – Ecnerwal
    May 26, 2023 at 22:31

2 Answers 2


For the Eaton CHN230SUR or CHN250SUR you are considering, you look at your panel and say:

  • "Well I don't have any 30A dual poles, but I have 50A dual pole so I'll get the 50"
  • "Well I don't have any 50A dual poles, but I have 30A dual pole so I'll get the 30"
  • "I don't have either of those sizes but I have two free spaces" and pick one at random.
  • "I have both of those sizes" and pick one at random.
  • "I have two free spaces" and pick one at random.

They appear to be made for folks with full panels that want to add an SPD, or for folks that want the potential extra circuit if the panel isn't full. Given the surge ratings are identical, just pick one.

  • thanks for your feedback, that makes total sense. May 28, 2023 at 18:31

You're misunderstanding the Eaton CHN2x0SUR products.

If your panel is full but you have a 30A dryer circuit, you can install the CHN230SUR to replace your dryer breaker, and now you have the dryer on a 30A breaker like before, but also a surge protector you didn't have before.

If your panel had no water heater or dryer but had a 50A range, then the '250SUR.

They are the exact same surge protector either way. It doesn't relate to the breaker, the breaker's only role is to let the dryer work :)

That said, I am not a fan of space saver surge protectors. I feel a limited package size reduces how much protection they can fit in. But I am not a surge protector designer.

  • Thanks for your feedback, that makes total sense. May 28, 2023 at 18:31

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