Surge Protection Device

M

mhosier

Member
Location
Manteca, Ca
Just completed an NFPA class in which they took the stance that a surge protection device is required at BOTH the MSP and any sub panel location. I expressed the opinion, based on 230.67, that a surge protection device at the main meets the minimum intent of protection. Is this incorrect? In places like California, we are required to prewire for battery back up/critical load panel in new SFD. So, based off their class, it would be required at the MSP, the critical load back up panel, and the other sub panel that is needed due to breaker space from the GFCI and AFCI requirements. Any feedback would be appreciated.

Respectfully,

Micheal
 
Going to depend on which version your locality is on, but I'm of the opinion that you can never have too much, but you can always end up just a couple joules short.
 
They got a little mixed up there. The 2022 California Electrical Code introduced surge protection requirements to CA, 230.67. That section is still there in the 2025 code with a minor addition (effective Jan 1, 2026) but is basically the same for the purposes of this conversation.

This cycle did add new requirements found in 225.42 which does require surge protection whenever "a feeder supplies any of the following": Dwelling units, dormitory units, guest rooms/guest suites (R-1), and patient sleeping rooms.

260.67 has an exception in both the 2022 and the new 2025 cycle: "The SPD shall not be required to be located in the service equipment as required in (B) if located at each next level distribution equipment downstream toward the load."

The exception didn't make much sense in the 2022 cycle, but now makes more sense. So, if you think "okay, 2022 added requirement A, and now the 2025 added requirement B, so both are required," you'd be missing the exception. It's an understandable mistake.

If the local jurisdiction made a local amendment to void that exception, it's only valid if they got it on the books before September 30th, 2025.
 
Joe.B said:
They got a little mixed up there. The 2022 California Electrical Code introduced surge protection requirements to CA, 230.67. That section is still there in the 2025 code with a minor addition (effective Jan 1, 2026) but is basically the same for the purposes of this conversation.

This cycle did add new requirements found in 225.42 which does require surge protection whenever "a feeder supplies any of the following": Dwelling units, dormitory units, guest rooms/guest suites (R-1), and patient sleeping rooms.

260.67 has an exception in both the 2022 and the new 2025 cycle: "The SPD shall not be required to be located in the service equipment as required in (B) if located at each next level distribution equipment downstream toward the load."

The exception didn't make much sense in the 2022 cycle, but now makes more sense. So, if you think "okay, 2022 added requirement A, and now the 2025 added requirement B, so both are required," you'd be missing the exception. It's an understandable mistake.

If the local jurisdiction made a local amendment to void that exception, it's only valid if they got it on the books before September 30th, 2025.
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Thank you, that was my opinion too but they were adamant they’re both required.
 
I've been to a lot of trainings and I've learned to get the instructors email. Rather than de-railing the class to question something I think is wrong, I'll make a note to research it later. A simple email will often clear things up for them. We're all human and even the best instructors will get things wrong. In this case I would simply email the instructor with the quoted text of the code and ask "what's this exception meant for then?"
 
Isn't the scope of 225 outside feeders? So it would only apply to feeders to detached dwellings, dorms, etc. So if the subpanels are in a building and assuming the main panel to that building has an SPD, I don't see how 225 could require anything inside that building past its main source. I assume also the reference is to the California code, so maybe they have expanded the scope, but that would be unusual. The CA wording also doesn't seem much different than the NEC.
 
"Outside Branch Circuits and Feeders"

I wish the codes would use oxford commas, because you could read this either way:

Outside _ Branch Circuits and Feeders

or:

Outside Branch Circuits, _ and Feeders

In other words, does "outside" only apply to branch circuits, or is the intent to state "Outside Branch Circuits and Outside Feeders"

I've delt with this a few times in code enforcement issues and I generally error on the side of caution. This is why AHJ is defined, and why they are charged with making that determination. So even if we all agreed on one interpretation, another AHJ could have a different view, and it their town, it's their rule.
 
Both the branch circuits and feeders are  outside.
It makes sense to treat feeders and branch circuits as being indoor or outside rather than saying it doesn't matter where the feeder is but outside branches need to be treated differently.

It is fairly common in the industry to require SPD protection at the point of entry  into structures.
 
Joe.B said:
In other words, does "outside" only apply to branch circuits, or is the intent to state "Outside Branch Circuits and Outside Feeders"
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For Article 225, it's definitely the latter. I.e. "Outside (Branch Circuits and Feeders)" [Since the phrase "A and Outside B" is available, if you want Outside to apply to only one of A and B, you just put that item second, along with the modifier Outside.]

On the SPD requirements, in Chapter 2 of the 2025 CEC (based on the 2023 NEC), I find: 215.18, 225.42, 230.67, and 242 Part II. Seems to me that 225.42 is entirely redundant, as any outside feeder is still a feeder and must comply with all of Article 215, including 215.18.

If a dwelling unit has all of its loads supplied by a single feeder or service, then a single SPD suffices to satisfy 215.18 or 230.67 as applicable. [Of course, if you choose to use 230.67(B) Exception, you may need more than one.] But you could having a dwelling unit supplied by two different feeders as per 225.30(B). In that case 215.18 would apply to each of those feeders, so you'd need more than SPD.

Cheers, Wayne
 
wwhitney said:
But you could having a dwelling unit supplied by two different feeders as per 225.30(B). In that case 215.18 would apply to each of those feeders, so you'd need more than SPD.
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BTW, to have consistency and to have the above be true, the phrase "supplying a dwelling unit" needs to be understood as "bringing power to the dwelling unit from a location outside the dwelling unit." That way internal feeders within the dwelling unit that supply only part of the dwelling unit loads don't become subject to 215.18, which could lead to a proliferation of multiple SPDs being required within a dwelling unit.

If I'm correct that is the intent, the wording could be clearer.

Cheers, Wayne
 
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