Does the requirement to install an exterior emergency service disconnect apply to when an electrical panel replacement will be performed to an existing dwelling? Or only to new electrical services?

Another question pertaining to existing dwellings. Is whole house surge protection required when an electrical panel replacement will be performed?

We’re planning on having the 200A panel replaced with a new modern 200A panel. This is the dwelling I mentioned in my recent thread where one contributor brought up the service disconnect but said It may or may not be required

The service conductors leave the meter, penetrate into the dwelling, and go directly into the whole house 200A electrical panel. The main 200A breaker in the panel currently serves as the main service disconnect.

The NEC2020 introduced language on replacement but it's not all that clear whether article 230 is applicable to panel replacements on existing dwellings. Some nfpa.org publications reference section 230.85 stating, it is a requirement to have an exterior emergency disconnect not only for all new electrical services, but also when electrical service is modified or upgraded.

Is section 230.67 referencing an outdoor emergency disconnect requirement for a panel replacement to an existing dwelling?

If it’s not entirely correct that a meter can and riser would not need replaced when a panel replacement is performed, then when might a situation necessitate it when the electrical panel is replaced ?

Around five years ago, the utility replaced the old (original) meter on the cabin with a digital read out type and never gave us prior notification they were going to

2 Answers 2


In my non-expert opinion and based on limited personal experience, the key phrase is:

electrical service is modified or upgraded

TL;DR You are not modifying or upgrading your service so the new rules don't apply

A very common situation is that an older 100A (or similar, anything less than 200A) service is upgraded to 200A. That is a heavy up. It is commonly done when the original panel is replaced, whether the reason for the replacement is:

  • Increased electric power demand (i.e., actually need a heavy up)
  • Replace a dangerous panel (Zinsco, etc. or damaged due to corrosion, etc.)
  • Add more circuits (this can be done to a limited extent by adding a subpanel, but there are often practical limits to what you can do without replacing the main panel)
  • Replace Rule of 6 panel with a main breaker panel
  • Add GFCI and/or AFCI breakers if no GFCI or AFCI breakers are available for the old panel
  • Add a generator interlock
  • Add solar power
  • Add whole house generator or battery backup

Only the first of these requires an increase in service. But many utilities and/or jurisdictions will use the excuse of a full panel change with existing service below 200A to be treated as a heavy up. Once you are in a heavy up situation, in certain respects it is very much like new service. In particular, everything from the utility pole to the main panel is likely to be replaced.

In reality, not everything needs to be replaced. For example, if the meter was already replaced with a 200A-capable smart meter then it is very likely that the utility will reinstall the exact same meter when done. Or the feed wires (service drop) from the pole to the weatherhead may have been replaced a few years earlier when the utility upgraded wiring in the entire neighborhood and so those wires are already 200A capable (but then again, they may do it anyway...). Or the utility may choose to not replace the service drop until they determine (based on the smart meter) that you regularly exceed a particular demand level.

But once they are, at least nominally, requiring replacement of everything from the pole to the main panel, they can require upgrade of any of those components to current (per local rules/NEC) standards. That can include requiring an outside disconnect at the meter.

It should not include surge protection as that is normally inside your main panel and straight functional replacement does not normally trigger upgrade requirements. Move the main panel to a different place in the house or make the old main panel a subpanel with a new main panel on the other side of the house feeding it and you likely will need to add surge protection.

Similarly, main panel replacement (heavy up or not) does not normally trigger requirements for GFCI and AFCI on any existing circuits. Add new circuits and the requirements apply.

Nor does it trigger requirements to have dedicated bathroom, kitchen or laundry circuits - if they were legal when originally installed and you are doing a straight replacement of the panel at one end of those circuits then you don't need to suddenly add more circuits to meet the latest rules. But renovate a bathroom at the same time and the rules will likely apply.

But your situation is a little different. It is not a heavy-up because you already have 200A service. With a heavy-up the utility would pull the meter and you would need a new meter pan and a new cable from the meter to the main panel, you don't need any of that. You need the meter pulled so that the main panel can be safely replaced, but the service is not changing and the feed (pole to weatherhead to meter to main panel) is not changing. Therefore, there should not be any need to satisfy any new requirements in the "weatherhead to meter to main panel" area.

All that being said, a jurisdiction and utility could make such a rule. But as I understand it, that would not be the usual way things work with changes in the NEC.

  • Just want to be clear on one point because you mentioned the Zinsco brand. This panel actually is a 200A Zinsco. So excluding that fact and taking under careful consideration everything else mentioned, this would still NOT be a "heavy-up" then ? Am I correct? Commented Sep 3, 2023 at 17:25
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    Correct. I used that as an example of "reason why you might replace a panel even though service is already 200A". It is "less than 200A to 200A" that makes it a heavy up. Already 200A, not a heavy up. (Unless you upgraded to 320/400, of course.) Commented Sep 3, 2023 at 17:31

Yes, it's required

The answer to your question in NEC 230.85(C):

(C) Replacement

Where service equipment is replaced, all of the requirements of this section shall apply.

Exception: Where only meter sockets, service entrance conductors, or related raceways and fittings are replaced, the requirements of this section shall not apply.

Given that your main panel is clearly "service equipment" as per the NEC, then you'll have to do this, which'll require a changeout from a standard meter socket to a meter-main given the configuration of your service equipment. Note that you'll need a ringless unit that has either a horn or a lever bypass fitted to it to meet Penelec service requirements, and will likely need to use a unit with an "over/under" configuration : the Siemens MM0202B1200RLC fits the bill, as well as a variety of 8 space units with feed-through lugs. (Square-D, Milbank, and Siemens all make units that look to be suitable for this; if Penelec is being particularly persnickity, then a Milbank U5168-XTL-200-KK-BLG will certainly do the trick.)

And yes, changing out that Zinsco firestarter is a bloody good idea

Since your existing panel is a Zinsco, it belongs headed to the smelter to be permanently converted into something more useful (such as beer cans). Once you get the emergency disconnect taken care of, I'd replace it with a 40-space or 42-space, 200 or 225A, main lug panel, given that you'll be fitting a four-wire feeder when you install the new meter-main.

  • Then they've made drastic changes. Every residential owner in the country has been affected by the requirements who're in a similar situation as us needing to swap a 200 amp for a 200 amp panel where its their main panel, which is considered service equipment according to the NEC. They're mandating this requirement on homeowners where it only seems to be for one and only one reason - first responders That's just my opinion anyway Commented Sep 3, 2023 at 18:20
  • While I disagree with ThreePhaseEel's interpretation (but he may be right, I may be crazy), in defense of the idea - those first responders are there to save your life and your house. The issue is "what kind of changes require this change". Also keep in mind that a panel change (whether 200/200 or 100/200) is a once in 20-30 years (or longer) event. (For me, >60 years, though did have a small subpanel added 20 years ago). In my case disconnect wasn't needed because AHJ slowed down implementation due to equipment shortages, but if needed I would have paid the bill. Commented Sep 3, 2023 at 18:31
  • Well, Either way, we're going to need to budget in the added cost without knowing what additional costs we might be incurring as being added-on. When I read into article 230, I thought I might've been reading too far into it. As for the 40 or 42 space main lug panel that ThreePhaseEel mentioned, we're talking about a cabin. The sq footage of the entire place is about 1300 (maybe1400 sq ft max) which the homeowners insurance includes. A hot water heater, and a drop in range are the only two 240v appliances. Seriously Commented Sep 3, 2023 at 18:50
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    Maybe a smaller panel would be OK. But the difference in price between a 20 space 40 space panel is on the order or $100 or less, and the larger panel often includes some "bonus breakers". Admittedly you may not need to meet all current requirements, but a small - yet basic - house with current code (and your listed appliances) is minimum spaces: 2 water heater, 2 range, 2 kitchen countertop, 1 bathroom, 1 laundry, 2 dryer (unless you don't have one), 2 HVAC (unless you don't have any...), and figure at least 2 general receptacles/lighting - that's 14 spaces without anything fancy. Commented Sep 3, 2023 at 20:45
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    So you might put in a 20 space panel and find that is 100% full. For literally a few dollars more, get at least a 30 space panel and you will have room for future stuff. It doesn't affect your service feed. It doesn't affect working space requirement. Commented Sep 3, 2023 at 20:47

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