Mike Dolt Enterprises
Mike Dolt Enterprises
User: SteveO NE, Location: Northeast
Asked on: Tuesday, December 17, 2024 at 1:33 am EST
Answered on: Thursday, March 6, 2025 at 6:24 am EST
Question: I've attached an image to hopefully help paint the picture here but here is the scenario:2020 NEC277/480 4wire wye service fed by a pad mount transformer3 services all 3 phase 4 wire: 100A, 60A, 400A (cl320 self-contained)Services are cold sequenced with a meter switch in gear outsideThese meter disconnect switches would not comply with the requirements of 230.71 to be electrically isolated - each meter can has a separate bucket but its not fully isolated, though the dead front has built in barriers they are not vertical sections and the 3 meter disconnects are within the same enclosure.The meter disconnects do comply with 230.82 and 230.85The meter switches are service rated and have adequate KAIC for the available fault currentThere is absolutely nothing in this gear that can be serviced without utility coordinationThe utility does not lock these breakers, at this time but utilities are known to change their mind - they already did on these siteServices have separate service disconnects where the PE/N bond is for each servicethese are separate individual fused disconnects outside of the mod meter gear.these are grouped inside and comply with 230.71, 230.72Does cold a sequenced meter center require a main breaker with service disconnects located downstream and in separate enclosures from the meter center?Follow up: If yes, just because the code allows it, would you do it? Essentially are we just calling it what we want to get our way.Alternate Follow up: What if the 3 disconnects had barrier kits between them?The reason the question matters is because for reasons before my involvement, and beyond my control, this site has a lot of step-down transformers to 120/208, it's also very far behind the curve of ordering equipment and needs it yesterday. It is relatively easy to coordinate with the meter disconnects, but I worry about black-start with a 600A breaker there. A fuse would be fine but getting a fused disco integral to the cabinet adds nearly a year to the lead time - the utility won't let us install an upstream fused disconnect to the cabinet. The breaker that seems to have a curve with a reasonable margin of safety adds a metric crap ton of cost to gear that is already overrun because of a last-minute change of utility rules (the utility originally approved the project with 480V metering separate cold sequenced cans, now they mandate group metering which is 60k or so more)In some areas the utility is more controlling of disconnects ahead of the meter, which makes this a no brainer in that its POCO jurisdiction, I have no say. Here they don't care and people use these meter disconnects as their service disconnects and AHJs are used to that and expect it. I don't agree with this because, well, they could change their rules at any time and lock them, some AHJs seem confused about this and don't really understand the concept of a Meter disconnect - this has become easier since the introduction of the outside emergency disconnect but AHJs in this area are still confused so this site is going to be a challenge anyway because of the neutral bonds being inside at what I am calling the service disconnects.My personal take is that service disconnects and the requirement for two-six disconnects has nothing to do with the meter disconnects and that meter disconnects do not have to comply with the rule as a separate and distinct switch - its unmetered power and not serviceable without utility involvement anyway. This of course only has 3 disconnects but the issue of course is their electrical isolation from one another. I worry I am technically right, but I am pulling a technicality of wording to make what I want to do work, as I mentioned in my follow up question.I know similar questions have come up before but what I found seems more around the philosophy of modular metering with service disconnects/ hot sequenced (load side) disconnects.
Okay, this is a complex situation with a lot of nuances. Let's break it down and address your questions point by point, referencing the 2020 NEC where applicable.1. Does a cold-sequenced meter center require a main breaker with service disconnects located downstream and in separate enclosures from the meter center? NEC Perspective
Based on the NEC alone, the answer is no, provided that the downstream disconnects meet all the requirements for service disconnects.
230.70(A)(1) states the service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors. 230.71 allows for up to six service disconnecting means to be used. 230.72 requires these disconnects to be grouped and marked. The key is that your downstream fused disconnects, being grouped and each providing overcurrent protection for each service, technically fulfill the requirements for the service disconnecting means. 230.82 Meter Equipment. Meter equipment, including instrument transformers, shall not be connected to the supply unless connected through a disconnecting means as described in 230.71. The "Cold Sequence" Argument
The meter disconnects, being cold-sequenced, are before the service point. You're not performing routine work on them. Only the utility works on them, and they take responsibility for the unmetered power.
2. Follow-up: If yes, just because the code allows it, would you do it? Essentially, are we just calling it what we want to get our way?
This is where it gets subjective, and your concerns are valid. It boils down to risk assessment and future-proofing: Risk Assessment
You are right to worry about the utility changing their policies. If they decide to lock out those meter disconnects, you are stuck. However, if they have disconnects, and overcurrent protection that is independent and accessible you aren't going to be stuck.
Future-Proofing
Future upgrades or changes become much more complicated if the utility controls the only disconnect point.
Black Start
Your concern about black starting a 600A breaker is legitimate. Fuses are generally preferred for this reason, providing inherent coordination.
AHJ Acceptance
If the local AHJ is used to this arrangement, it makes things easier in the short term. However, AHJ interpretations can change.
Conclusion (Question 2)
If you can get away with using the downstream disconnects as your sole service disconnects, and if you are willing to accept the risk of potential future utility lockout and the challenges of the larger breaker for black start, you could do it. However, it's a calculated risk. Personally, I would lean towards avoiding this configuration if there's a reasonable alternative, even if it means extra cost and lead time, simply for the sake of long-term flexibility and control.
3. Alternate Follow-up: What if the 3 disconnects had barrier kits between them?
This addresses the concerns about the meter disconnects complying with 230.71. Barrier kits would improve safety and could sway an AHJ. Barrier Kits and Isolation
If the barrier kits are sufficient to provide true physical separation between the disconnects (meaning a tool couldn't accidentally slip and contact another phase or disconnect), it would be a stronger argument that each disconnect is effectively "isolated" and therefore could qualify as a service disconnecting means.
Still Doesn't Address Utility Control
However, adding barrier kits does not address the fundamental issue of the utility controlling these disconnects. They might still decide to lock them out. So, barrier kits might make it safer but don't address the core concern of reliance on the utility for disconnecting the service.
Your Personal Take & the Neutral Bond Issue
You are not wrong in saying the service disconnect requirements are not necessarily related to meter disconnects. Meter disconnects are before the service point. The NEC does not explicitly require a service disconnecting means at the meter location, particularly in cold-sequenced arrangements. You are correct to be cautious. Even if it's "technically" compliant, relying on a setup that depends on continued utility cooperation is risky. Neutral Bond
This is a huge red flag with how AHJs accept things. The POCO doesn't control your GEC system. While the service is technically the point where it exists, in practice, it could cause a lot of issues with parallel neutral paths and objectionable current flow. This alone might be enough to force you to have separate service disconnects ahead of the meter disconnects.
Recommendations and Next Steps
Talk to the Utility (Again)
Explain your concerns about potential lockout. Inquire about the possibility of them locking out the disconnects in the future. Get something in writing if possible (even email). If they are likely to do it, you have a stronger case for justifying the additional cost and lead time.2.
Talk to the AHJ (In Writing)
Get their interpretation in writing. Explain the situation, your concerns, and your proposed solutions. Emphasize the potential for utility lockout and the neutral bond issue. A written response will protect you later.3.
Document Everything
Keep a thorough record of all conversations, emails, and documents related to this decision.4.
Explore Alternatives
Keep looking for alternative solutions that reduce lead times while still meeting your needs. For example, could you use a different type of fused disconnect that is more readily available? Could you pre-order certain components now to mitigate delays later?5.
Risk Mitigation Plan
If you decide to proceed with relying on the meter disconnects, create a risk mitigation plan. This plan should outline the steps you will take if the utility locks out the disconnects, including the cost and time required to install a service disconnect.
In Summary: While you might be able to argue that your proposed configuration is technically compliant with the NEC, it's a risky approach due to reliance on the utility. Proceed with caution, document everything, and carefully weigh the risks and benefits. The best approach would be to minimize reliance on the POCO, and to make it clear who is responsible for the GEC system. While that might be the POCO, its unlikely, and the AHJ will make you fix it either way. Flag for review