Thread: How many main panels can one condo have?

So here is the set up on a condo I reviewed.

Outside has bank of meters and shut offs. One is for the unit I inspected. The unit inspected has the exterior wall with the shut offs (mains).

The wire to the panel in the inspected unit's basement is very short.

Basement panel is wired as a main panel in the grounds and neutrals are not kept separate and there is one main switch properly rated to shut it all down.

Can this be considered ok? Or should that basement panel have its grounds and neutrals separated until they can be bonded at the exterior main?

Thanks in advance for your input.

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Your use of the term "main panel" for everything confuses your question.

A condo building is one building.

A building may have one service up to 6 service disconnects.

Given that the condo building will have at least one 'house' panel, that could be one of the 6 allowed service disconnects.

That leaves 5 service disconnects for 5 condos.

Otherwise, there is likely 1 service disconnect for the building which feeds the house panel and the condo panels.

Each of those panels would not be service panels, just 'remote' panels.

Each of those panels would be fed from a breaker from the service panel, possibly contained wwithin the service equipment panel itself, possibly in a panel fed from the service equipment panel.

The answer to your question depends on how many condo units there are and how it was set up.

Fair enough.

This is a three unit condo building. There are three disconnects at the exterior of the left end unit. I was inspecting the left end unit.

So the left end unit has what I would call a main disconnect at the exterior. At the interior of its basement, just opposite all three and in particular, this one unit's main disconnect is another distribution panel (sub panel) which is wired as a main panel as I stated above.

Is that allowable or must it be a sub panel type installation with grounds and neutrals separated?

After the main disconnect grounds and neutrals are seperate . There can only one location where the building grounding system , grounding electrodes and or water pipe if copper , and neutrals come together. That is at the service. Any thing after the main service is a branch circuit , Even to other panels .

This ensures the electrical potential of any conductive material is the same for people's safety and hopefully keeps lighting out of the building or it goes safely to ground.

Originally Posted by Tom King

This is a three unit condo building. There are three disconnects at the exterior of the left end unit. I was inspecting the left end unit.

Okay, there is one building with three units, and each unit goes from top to bottom (including or not including the basement?), or are the three units one above the other?

If the three units are side by side by side, each likely has its own entrances and exits, and if the basement is separated into three sections under each unit, there it may be that there are no common circuits (not even exterior lighting, receptacles, etc? unusual, but possible).

Starting with the above presumption - there is one building with 1 service which has 3 service disconnects (as it allowed).

With this presumption, all panels downstream of these 3 service disconnects are required to have the neutrals isolated from ground.

So the left end unit has what I would call a main disconnect at the exterior. At the interior of its basement, just opposite all three and in particular, this one unit's main disconnect is another distribution panel (sub panel) which is wired as a main panel as I stated above.

You called it a "sub panel" (there are no "sub panel"s), it may be a "service equipment panel" or it may be a 'remote panel' (to use a better term).

To clarify, the 3 service disconnects mentioned previously are, as stated previously, on the exterior, and the 3 disconnects mentioned just above are those 3 exterior service disconnects, and the other panel is in the basement on the other side of the wall the 3 service disconnects are on?

The panel in the basement also has a main service disconnect, correct? If so, and if the basement is common to all 3 units, then that panel may be the house panel and be a 4th service disconnect. While 4 service disconnects are allowed on one service, they are required to be grouped together and labeled what they are for.

If the panels and disconnect in the basement is a 4th service disconnect, it should not be in the basement, it should be on the exterior with the other service disconnects.

Is that allowable or must it be a sub panel type installation with grounds and neutrals separated?

IF that panel in the basement is a 4th service disconnect panel, the neutral is required to be bonded to ground at that service equipment.

IF that panel in the basement is not another service equipment panel, regardless of what it is for, the neutral needs to be isolated from ground.

If you discontinue using the terms 'main panel' and 'sub panel' and think in terms of "service equipment panel" and "non-service equipment panel" ('remote panel' is a simpler term), then confusion of where the neutral is bonded to ground and isolated from ground goes away as the neutral is bonded to ground at "service equipment", and is isolated from ground 'downstream of the service equipment'.

The key will be this: is that panel in the basement a 4th "service equipment" panel or not? And that has not been clearly determined as yet.

Originally Posted by Tom King

So here is the set up on a condo I reviewed.

Outside has bank of meters and shut offs. One is for the unit I inspected. The unit inspected has the exterior wall with the shut offs (mains).

Metering box with breakers or metering box with remote disconnect upstream?
An image would help.

Originally Posted by Tom King

The wire to the panel in the inspected unit's basement is very short.

I suspect the that is the service entrance feed, SEC Either overhead service drop or underground laterial entering into the building.
An image would go a long way in helping I believe.
Also, I do not think lenght has any reference.

Originally Posted by Tom King

Basement panel is wired as a main panel in the grounds and neutrals are not kept separate and there is one main switch properly rated to shut it all down.

That would be the main service disconnect.

Originally Posted by Tom King

Can this be considered ok? Or should that basement panel have its grounds and neutrals separated until they can be bonded at the exterior main?

I think you are looking at the service/and remotes backwards.

Originally Posted by Tom King

Thanks in advance for your input.

You are welcome. Images would go a long way in sorting your questions out..

Originally Posted by ROBERT YOUNG

Images would go a long way in sorting your questions out..

Even a drawing of what is located where would help, but most important is knowing what is located where to be able to label the drawing - knowing the use/purpose of the disconnects and panels (such as that basement panel) may completely change the answer.

A sketch showing the structure and the units may also help, especially the basement - this is mainly because the condo only contains three units, so one would expect either one main service disconnect or four main service disconnects ... three main service disconnects indicates that someone may be paying for the house/common lights and stuff.

Originally Posted by Jerry Peck

Even a drawing of what is located where would help, but most important is knowing what is located where to be able to label the drawing - knowing the use/purpose of the disconnects and panels (such as that basement panel) may completely change the answer.

A sketch showing the structure and the units may also help, especially the basement - this is mainly because the condo only contains three units, so one would expect either one main service disconnect or four main service disconnects ... three main service disconnects indicates that someone may be paying for the house/common lights and stuff.

I have seen what might be there (except for the basement panel as there are no basements here) - a development of townhouses (what was originally planned as townhouses) on property which could not be rezoned, so they were turned into,, and built as, condos.

There were 43 buildings consisting of 4, 6 and 8 units. Each building had the service equipment panels and service disconnects on one end. Each unit had its panel in it, and each unit's panel was a 'remote panel' with no main panel disconnect, the neutral was isolated from ground in each unit's panel.

There were no 'common' electrical items for each building, there were, however, a common area service equipment panel for the common area lighting (street lights, signage, etc).

I did AHJ inspections on those from the slabs up, and even though each building 'looked like' townhouse buildings, each building was its own condo building and own condo association, within the master association which owned all the common elements - pool, tennis courts, streets and lights, etc.

I am explaining the above because, three service equipment disconnect on the end of the building is not necessarily 'wrong' ... but that mention of 'basement' and 'basement panel' are red flags that things 'might' ... 'might' ... not be right - that more information is needed.

Things are not always cut and dry as to what goes where, what is where, and why it is where it is.

That said ... that basement panel triggers the most questions.
- s it another service equipment panel? If so, it should not have the service disconnect down in the basement.
- Is it for common electrical? if so, is the basement accessible to all condo owners, or only to the unit above it?
- The list is not endless, but those are just a couple of questions to start with.

Originally Posted by Jerry Peck

A sketch showing the structure and the units may also help, especially the basement - this is mainly because the condo only contains three units, so one would expect either one main service disconnect or four main service disconnects ... three main service disconnects indicates that someone may be paying for the house/common lights and stuff.

I concur. One main service.
Also, it is usually the case where a separate meter & disconnect is metering shared electricity for lighting and heating on common areas, unless there are no common areas.

In my area, several condo/PUD/townhome developments will have a large commercial box with individual meters and disconnects at one end of each building. There might be 3 residential units per building, there may be more. Most of the time they are 125 amps. In each unit, another panel is installed. Everyone but Jerry calls them sub panels, even though its not the "correct" term.

Tom, this would be a typical electrical distribution center that I encounter inspecting stacked high rise condo buildings.
Prior the inspect I make requests to the association through the broker/client to allow me access to mechanical/electrical utility rooms, pools, spa's, storage lockers, the garage and roof. Requests are typically respected.

electrical service distrobution.JPG
electrical service room.jpg
The remote (sub) panel is in the habitable space.
electrical service panel.JPG


Tom I can not answer your valid question of,"How many main panels can one condo have?"
If you stop to think about the question, it depends upon the development/layout.

Jack, Jerry, or anyone else that cares to take a swing at answering this question, how did the term (subpanel) become the term most used to describe a remote service panel?
Thank you.

Originally Posted by Jack Feldmann

Everyone but Jerry calls them sub panels, even though its not the "correct" term.

Not everyone.

And many who do have confusion over where the neutral is bonded to ground.

Seems that the simple solution is to think of them the correct way.

Not sure why some are so resistant to using correct terms and simplifying the understanding of what/why.

Originally Posted by ROBERT YOUNG

Jack, Jerry, or anyone else that cares to take a swing at answering this question, how did the term (subpanel) become the term most used to describe a remote service panel?
Thank you.

First was the service equipment panel - those old panels with pull out mains and cartridge fuses and/or those safety switches which the handle on the side.

Those fed other panels (in the case of the safety switch) using feeder conductors. The panels being fed by the feeders had the feeders off a fuse, thus those panels were 'subfed' from the previous panel (or safety switch).

The 'subfed-panel' became shortened to 'sub-panel' ... it was ... at that time ... subfed from the service equipment panel which contained 'the mains' (those pull outs or fuses in the safety switch), thus those panels were 'the mains panel', which became shortened to 'main panel'.

However, in modern day systems, it is not uncommon to have a service equipment panel with only the service equipment mains or a limited number of breakers for branch circuits, with a breaker feeding a downstream panel, an that panel may feed a panel downstream from it.

Thus there is the service equipment panel and all other panels.

Many panels which are referred to as 'main panels' have nothing to do with the service equipment panels.

In my area, I will occasionally see homes where the service equipment is on the exterior of the house/garage which houses only the meter and a main disconnect. Then somewhere inside (often the garage) will be the panel which contains all of the branch circuit breakers. In many cases people (homeowners, agents, even electricians) will refer to that as the "main panel". Which, from a certain point of view, is fine.

At Jerry's suggestion (or was it nagging? ), I began using the term "service equipment" in my reports - probably a dozen years ago. I have yet to have someone call me and ask what that means.

Periodically, I read some post where an inspector has stated that home inspection should be treated as a "profession" rather than a "trade". One hallmark of a profession is terminology. Doctors, lawyers, engineers, etc. all use very specific, defined and recognized terms to ensure that they are accurately understood when communicating with peers. Doesn't it make sense to do the same? We use recognized terms for structural, plumbing and heating components... why not electrical too?

Originally Posted by Jerry Peck

First was the service equipment panel - those old panels with pull out mains and cartridge fuses and/or those safety switches which the handle on the side.

Those fed other panels (in the case of the safety switch) using feeder conductors. The panels being fed by the feeders had the feeders off a fuse, thus those panels were 'subfed' from the previous panel (or safety switch).

The 'subfed-panel' became shortened to 'sub-panel' ... it was ... at that time ... subfed from the service equipment panel which contained 'the mains' (those pull outs or fuses in the safety switch), thus those panels were 'the mains panel', which became shortened to 'main panel'.

However, in modern day systems, it is not uncommon to have a service equipment panel with only the service equipment mains or a limited number of breakers for branch circuits, with a breaker feeding a downstream panel, an that panel may feed a panel downstream from it.

Thus there is the service equipment panel and all other panels.

Many panels which are referred to as 'main panels' have nothing to do with the service equipment panels.

Thank you for your explanation. I loaded in on word doc.

Originally Posted by Gunnar Alquist

At Jerry's suggestion (or was it nagging? ),

That's about the time I began using an avatar - if you are not in one of those (submarine) you are not looking at a sub panel (also shown in my avatar) .

Earlier this year I had an opportunity to actually see, and take photos of, a "sub panel" ... and I posted those photos.


Gunnar is correct - as professionals, do we call a beam 'that piece of wood holding things up''? Do we call "rafters" "trusses"? Of course not.

So if you are at the service equipment, it is called "the service equipment" ... and that is where "the mains" are located.

Down the road from my house is an earth berm house (grass lawn on top). In that case, could the main be a sub since its underground?
I'm really confused now!!

Originally Posted by Jack Feldmann

Down the road from my house is an earth berm house (grass lawn on top). In that case, could the main be a sub since its underground?
I'm really confused now!!

Jack, I don't mean to chime in on a question you asked Jerry but, I think the home would have to be under water for the terminology sub panel to be truly relevant.
You could say the home is well grounded though.

Originally Posted by ROBERT YOUNG

Jack, I don't mean to chime in on a question you asked Jerry but, I think the home would have to be under water for the terminology sub panel to be truly relevant.
You could say the home is well grounded though.

I meant as in...subterranean, or under ground. Not under the sea.