I've attached an image to hopefully help paint the picture here but here is the scenario:
2020 NEC
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.
2020 NEC
- 277/480 4wire wye service fed by a pad mount transformer
- 3 services all 3 phase 4 wire: 100A, 60A, 400A (cl320 self-contained)
- Services are cold sequenced with a meter switch in gear outside
- These 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 230.85
- The meter switches are service rated and have adequate KAIC for the available fault current
- There is absolutely nothing in this gear that can be serviced without utility coordination
- The utility does not lock these breakers, at this time but utilities are known to change their mind - they already did on these site
- Services have separate service disconnects where the PE/N bond is for each service
- these are separate individual fused disconnects outside of the mod meter gear.
- these are grouped inside and comply with 230.71, 230.72
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.
