I need an answer...Quick

[David P. Valley]

All the years I've been doing inspections, I've never ran into this situation.

Ok...Here's the situation. See the picture below.

"Click To Enlarge"


I have several 50 Amp metered panels wired into a 200 Amp service. There is only one (1) main disconnect (Long Handle) at the main SE panel. This will shut down the entire building. The other smaller metered panels do not contain main disconnects per panel and there are no other main disconnects anywhere for these individual smaller panels.

Are these considered to be sub-panels/load side equipment, where all the grounds should be bonded?

And aren't individual shut-offs required somewhere, for these smaller panels?

[Marc D. Shunk]

You've got your main disconnect ahead of the meters, so your main is handled there. Each tennant panel does not require a main, but does need to be wired as a subpanel, since the main bonding jumper or screw will be in the main disco and the grounding electrode conductors will be there also.

What you picture there is called "cold sequence metering".

[David P. Valley]

Originally Posted by Marc D. Shunk

You've got your main disconnect ahead of the meters, so your main is handled there. Each tennant panel does not require a main, but does need to be wired as a subpanel, since the main bonding jumper or screw will be in the main disco and the grounding electrode conductors will be there also.

What you picture there is called "cold sequence metering".

Marc,

That's what I thought and that's what I had told my client, but wanted a firm answer before I finalize my report.

So this situation does indeed require bonded grounds and floating neutrals in every panel after the main SE.

Thank you kindly, Sir.

[Marc D. Shunk]

Originally Posted by dvalley

So this situation does indeed require bonded grounds and floating neutrals in every panel after the main SE.

Yup. Your terminology is a little weird, but I get your meaning.

What screws people up here is that they look at a situation like this as 5 services, but what you really have there is one service, metered 5 times. What's interesting is that there is an exception that will permit the neutral to bond the meter cans internally if they're mounted directly adjacent to the main disco, as you have pictured. It's only 4-wire inside the panels. There's a heck of a lot of confusion out there related to exacltly how you do these apartment building setups, but it sounds like you pretty much had it straight to begin with and just wanted confirmation.

[Greg Fretwell]

There are AHJs that consider this whole cludge "service equipment" and don't expect to see the isolated ground until it leaves this assembly in a 4 wire feeder to the units. Certainly the panel in each unit should be treated as a sub.
I also believe each unit needs a disconnect.

[David P. Valley]

Originally Posted by Greg Fretwell

There are AHJs that consider this whole cludge "service equipment" and don't expect to see the isolated ground until it leaves this assembly in a 4 wire feeder to the units. Certainly the panel in each unit should be treated as a sub.
I also believe each unit needs a disconnect.

That's what I had thought also, and that's the reason why this subject came up, as I wasn't 100% postive. I've always seen this type of electrical installation, but never with the individual disconnects missing.

So now I have two different opinions. I'm going to add "Recommend disconnects at each sub-panel" to my report.

Thank you Greg.

[Marc D. Shunk]

Originally Posted by Greg Fretwell

There are AHJs that consider this whole cludge "service equipment" and don't expect to see the isolated ground until it leaves this assembly in a 4 wire feeder to the units.

They'd be entitled to that opinion, but this absolutely doesn't square with the NEC one bit. After you hit the disco, you have zero relief in the NEC from running 4-wire. It would be nice if each tennant panel had a disco, but there's no mandate for that either.

[Greg Fretwell]

Sad but true. Fortunately a HI only has the responsibility to warn the client about things they will hate later. If the guy in 101 is having his panel serviced it may be necessary to power down the whole building to do this work safely.

[David P. Valley]

Originally Posted by Greg Fretwell

If the guy in 101 is having his panel serviced it may be necessary to power down the whole building to do this work safely.

Very good point Greg.

I knew there was something wrong here when I inspected it yesterday.

Thanks guys.

[Paul W. Abernathy]

David...in your picture you have posted.....what are the BOXES ( in your actual visual description ) below the meter housings.

Since you label the meters themselves and the 200A disconnect.....but not the boxes below the meters.......just for additional clarrification.

[David P. Valley]

Originally Posted by pabernathy

David...in your picture you have posted.....what are the BOXES ( in your actual visual description ) below the meter housings.

Since you label the meters themselves and the 200A disconnect.....but not the boxes below the meters.......just for additional clarrification.

Those are the individual breaker panels for each tenant, with no main disconnects in them.

Simply just breakers to individual circuits.

Do you have something to add?