I am planning on installing the CHSPT2ULTRA Type-2 surge protector on my outside main panel. I am planning on:

  1. turning off main being careful to note that the utility service lines and the terminals they connect to inside the panel remain live
  2. using a knockout closest to neutral bar for the CHSPT2ULTRA
  3. adding a 2-pole 50amp breaker in the open slot under existing breakers
  4. Connecting the White wire to the neutral/ground bus bar. (pictured on right)
  5. Connect the Green wire to the same neutral/ground bus bar.(looks like there are two open terminals)
  6. Connect the Black and Red wire to the 2-pole 50amp circuit breaker added in step 2
  7. go get a beer

Would this be a correct and efficient installation? Am I missing anything that might improve performance from the surge protector?

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outside main panel cover on

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  • Seriously well done for a first post! Welcome to Home Improvement!
    – FreeMan
    Jul 25, 2020 at 23:58
  • Thanks! basically I just want to make sure this is a correct installation and that I'm not missing any details that might make for more effective performance. Long time lurker, first time poster. I've gleaned so much great info from the site over the years!
    – james_m
    Jul 26, 2020 at 0:22
  • By the way if you ever decide you want to make use of all 16 spaces, note the part where it says "Fits box size B". It may well be a CH12L125R. Another one that fits box size B is CH16L125R. Acquire one, swap bus assembly, profit. Jul 26, 2020 at 2:19

1 Answer 1


Several ways to do that.

Fit a surge breaker

Replace the Dryer breaker with a CHSPT230 breaker, which is simply an Eaton surge suppressor built into a 30A breaker. The 30A breaker isn't for the surge suppressor, it's for any general 30A load. The point of that is to save you 2 spaces in your panel.

That means you'd install the CHSPT230 to replace your dryer breaker, or the CHSPT250 to replace your subfeed breaker (honestly the first one feels safer; dryers will always be 30A... but subfeeds might be upgraded, especially once you realize #6 wire can be breakered for 60A lol).

Your planned CHSPT2ULTRA device

Feed it from a 50A breaker, yes... except locate it right across from the main breaker. Move the other breakers down.

Why? Because, check your label, but most CH bus stabs are only rated for 140A. The 125A main, plus the 50A breaker across from it, is 175A on that bus stab. Whereas surge suppressors flow zero power, except when suppressing surges of course. So it is a good option for that limited "across from the main" breaker space.

By the way, if you want more spaces...

Your box is a "B" sized box, as stated on the label. As you might guess, other breaker panels also use a "B" sized box. One is the CH16L125R, which is 16-space and makes full use of the knockouts on your cover. One could be acquired, and its bus bars bolted up inside your panel, without the need to remove all the wires and tear the box off the wall.

  • Interesting. Didn't even know they made breaker surge protectors. Certainly is an option, even though i've already purchased the ULTRA and since I've been putting this project off it's WAY past the return window, I could always use both and put the ULTRA downstream in the sub-panel for "second-tier" protection. Seems like if I replaced the Dryer breaker with the Eaton breaker that the pigtailed neutral wouldn't reach across to the bus on the right?
    – james_m
    Jul 26, 2020 at 4:10
  • With my planned ULTRA device, not sure if I understand. If the CH bus is only rated for 140A then why is the 125 main and 60 sub side-by-side? wouldn't that put it at 185? Why wouldn't they have installed say the 30A dryer breaker next to the main. Are you recommending putting the ULTRA next to the main because it would be closest to main feed and furthest upstream? @Harper - Reinstate Monica
    – james_m
    Jul 26, 2020 at 4:21

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