Service requirements

[bigdog]

I looked at a multifamily building the other day built in 1955 Palm Beach County 6 units maybe 400 SF each. The building has a new (2009) 200A service with no sub panels for each unit or separate breakers for each unit.

Each unit has 3 circuits coming from the main panel. Building has a gas water heater, common laundry equipment and the units have gas mini ranges.
Is there an exception for each habitable unit not having it own 100A service?
Has this been grandfathered in.....until someone wants to modify this arrangement?

David

[Jerry Peck - Codeman]

After doing some research through my older NEC codes books, I find that in 1959 there was a minimum requirement of 60 amps if a switch was used, and 50 amps if a breaker was used, with the exception that dwelling units required 100 amps if ... if the computed load (based on the section the code referenced) exceeded 10 kw - otherwise there was only the 60/50 amp rating of the service to the building.

I could not find the same minimum rating requirement in my 1956 NEC or any of the older NEC codes I looked in, which indicates that the minimum requirement can into the NEC in 1959 ... after that building was built.

Additionally, for 400 sf apartments, if that section had been in the code it is likely that each 400 sf apartment would not have computed out to over 10 kw, which means that 100 amp minimum would not have applied anyway.

I looked at a multifamily building the other day built in 1955 Palm Beach County 6 units maybe 400 SF each. The building has a new (2009) 200A service with no sub panels for each unit or separate breakers for each unit.

Each unit has 3 circuits coming from the main panel. Building has a gas water heater, common laundry equipment and the units have gas mini ranges.

The key may be in information included in the above - where were the overcurrent devices located and did all occupants have access to the overcurrent devices?

Another question raised is what was the larger service for? Air conditioning units? If so, then the apartments may have been rewired and it is possible (not enough information given) that the apartments would have needed to have been upgraded to include their own remote panel ("sub panels" are only found in "submarines"). Was the upgrade of the service permitted? What did the permit say the scope of the work was? The permit scope of the work was likely kept to reflect minimal work and thus not trigger the full upgrading of each apartment.

Has this been grandfathered in.....until someone wants to modify this arrangement?

"Grandfathering in" is a misnomener - the term should be 'allowed to remain as it legally existed', and if it did not meet the code at the time, or changes took place which were not permitted, then it was no longer 'legally existing'. But those are things that would take a complete permit search and review of the building to the permits to determine and the original permits are quite possibly no longer available, or are incomplete if available.

[bigdog]

Thanks Jerry,
The service was permitted and the units somewhat rewired but but who knows what was the stated scope of the work. owners tend to not disclose all the work they are doing. Wall unit A/C's were added at some point.

Sub panel and "grandfathered in" are the only nomenclature (word of the day) I have ever known and most in the trades use them and know what your referring to. What would your preferred term be for differentiating a sub panel from a power or lighting and appliance panel with the main disco?

David

[Jerry Peck - Codeman]

David,

Sub panel and "grandfathered in" are the only nomenclature (word of the day) I have ever known and most in the trades use them and know what your referring to. What would your preferred term be for differentiating a sub panel from a power or lighting and appliance panel with the main disco?

There are two types of panels:
- service equipment panels
- panels other than service equipment panels

The problem with the term "sub panel" is that it means different things to different people. Most people who use the term "sub panel" also use the term "main panel", which has different meanings to different people.

Starting with "main panel" - let's say there is a service equipment panel on the outside of a house (using house just as a type of building) and that service equipment panel includes the main service disconnect only (or maybe it contains a couple of other breakers for A/C units, sprinkler pump, pool pump), and there is an inside panel which has all the other breakers for all the other circuits ... which one do many people think is "the main" panel? The inside panel will most of the breakers in it.

The term "sub panel" came from the fact that there is a service equipment panel and sub-fed from that service equipment panel is a remote panel (remote from the service equipment, the two may be side-by-side). That "sub fed panel' became shortened to "sub panel". That remote panel (non-service equipment panel) may be a distribution, power, or lighting and appliance panel, its use is not related to the fact that it is either a service equipment panel or is not a service equipment panel.

The main mix-up comes in with "where is the neutral bonded to ground" - and that is "at the service equipment panel" ... all other panels are non-service equipment panels (not serving as service equipment, regardless of where the panels be physically be located).

Remember the "old days" where there was a panel (usually in the kitchen) which had pullouts? That was the one and only panel, it was the service equipment panel, and the pullouts were the main service disconnects (there were typically two mains, one for the range, and the other for the fuses located below the pull outs - i.e., the pull outs were "the mains". That panel became known as "the mains panel" because that was where "the mains" were, over time it was shortened to "main panel" ... nonetheless, though, that panel was and is "the service equipment panel".

There are service equipment panels, and panels which are not service equipment, and panels which are not service equipment panels are remote from the service equipment panels ("remote" is not used as meaning 'a great distance from', just meaning 'remote from' or 'not part of' the service equipment) and those panels which are not service equipment can have any number of uses - but being used as service equipment is not one of those uses.

The reason I point out the difference, and that "sub panels" are found in "submarines" is because of the common confusion of where the neutral is bonded to ground

The typical home owner only 'knows' what they are told, and most often does not even 'know' that, they are just repeating words someone told them. If people would tell them this is the 'service equipment' panel where the main service disconnects are' ... those same people would 'know' that. And if people would tell them this is your 'electrical panel', they would 'know' that too (and that would be an easy one to understand as that is where 'all those breakers are').

The only panel which needs a name is the service equipment panel - the owners and occupants need to know where to go to shut off the electrical service (power) in case of an emergency.