Is this a correct installation of a whole house Surge Protector?

Note that it's not closest to the main lugs, will that matter?

I was unable to bring it closer to the main lugs since those had special breakers which I did not have and I did not want to mess with that wiring.

I have installed the Square D 80 whole house surge protector at the first available breaker that wasn't GFI. It's a brand new breaker rated at 30 A. I could not find a 20 A breaker at Lowe's so I opted for the next one up.

Should I have used a 20A?

Notice that one of the neutral wires has a slight bend to it and I've read to avoid drastic bends. Will that affect the surge protection?

Also, since it's not closest to the main lugs, will the breakers above the whole house surge protector still be protected or should I redo the whole panel?

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    Does that breaker power the suppressor exclusively? Or is it sharing the breaker with an appliance? Commented May 9, 2019 at 22:21
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    I take it you plan to flush-mount the surge suppressor into the wall as part of finishing the install? Commented May 9, 2019 at 22:30
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    The breaker powers it exclusively there is nothing else powering the breaker it's just straight into the protector.
    – tempnexus
    Commented May 9, 2019 at 22:51
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    @tempnexus, if you cut out a section of the panel's deadfront to feed in wires, it'll never pass an inspection. Part of the panel's job is to keep any fire that may occur safely inside the panel, and if you cut holes in it in a non-standard way, you can easily defeat that.
    – Nate S.
    Commented May 9, 2019 at 22:56
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    Cutting an appropriately sized hole for the surge suppressor in sheetrock can be basically free and would be the way to go so you can feed the suppressor into the panel through one of the panel’s knockouts. Not sure why you are saying it is more expensive to cut a hole in one vs the other. Commented May 9, 2019 at 23:50

1 Answer 1


You will need to flush-mount the protector, feeding the wires through a knockout

Since your panel is flush-mounted into the wall, and you generally are best off not modifying a deadfront if you can help it (while the UL listing on the loadcenter cabinet is not technically necessary, modifying the cabinet deadfront could confuse an inspector). Instead, you'll need to use a HEPD58MKF or HEPD80MKF flush mount kit to mount the surge suppressor into the drywall, along with the short length of flex conduit and supplied fittings to route the wires from the HEPD80 surge suppressor into the panel.

As to making a knockout for the surge suppressor wires to go through, you'll want to make a 7/8" hole in the panel's side (this is the actual size of a knockout hole for a 1/2" nominal conduit fitting) that is directly aligned where the breaker you put in for the surge suppressor is. The easiest way to do this is with a tool called a knockout punch; a cheap set will do you just fine. I would not use a drill for this; even with the panel dead, it's very hard to guarantee that stray chips from drilling haven't gotten places that would cause bad news when the power is turned back on.

That 30A breaker, it turns out, is OK after all

The instructions for the HEPD80 allow for the use of a 30A maximum breaker; this isn't an issue since the conductors to the SPD carry practically no current in normal operation, and the device can't generate an overload condition, so short-circuit/ground-fault protection is the only concern here, and UL has tested the device with 30A breaker protection.

Note that while it is possible to tap an existing breaker of suitable size to install a SPD like yours, that has the downside that an overload or short on that circuit will cause a loss of surge protection; as a result, it's recommended to do as you did and use a dedicated breaker for installing the SPD. (It's also possible to install the HEPD80 tapped directly off the busbar, but that has the downside that you have to kill power to the whole panel to service the surge protector, so having it on a dedicated breaker makes sense.)

  • I thought these knockouts were meant to be knocked out as with blows from a hammer driven punch or screwdriver positioned at a point of best effect, but when I removed mine I found it pretty hard to remove. Is it OK to bang away on a panel with breakers installed? I've seen an Eaton-Cutler Hammer panel with a surge protector fitted in an opening in the dead front. In that panel where are the leads to the surge protector connected? I assume on the house side of the main breaker, but exactly how is it connected-- through it's own breaker (e.g. 50 A 2-pole) or otherwise? Commented May 10, 2019 at 12:45
  • @JimStewart -- normally, with factory KO provisions, they're more of a "pryout" sort of thing (loadcenter instructions specify how to do it these days). In the Eaton surge panels, I believe they have their own breaker for the surge suppressor, but I'm not at all certain. Commented May 11, 2019 at 0:56

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