What size meter breakers required for this multi-family house?

[LA-Sean]

My utility is giving me a single drop with a Single Phase 400AMP Conductor rated a 80%. So technically only 320AMPs. I need to upgrade my current configuration to a 400 AMP Disconnect with a Meter Module Configuration of 3 columns with 4 Stackable Meter Column, 3 Stackable Meter Column , and 3 Stackable Meter Column. So, a total of 10 Meter Spaces. 3 of which are spares for Future development. I currently have a total of 6 Apartment Units with individual meters, and 1 Common Area Meter.

My first Question: If I have 400 AMPs Disconnect what is the highest load, I can provide my Apartment Subpanels without a disruptions? What should be the Breaker Size at the Meter for the individual Apartments and what should be the Breaker Size of the corresponding Apartment Subpanel. I have received conflicting answers from electricians. Some say, I am only limited to a maximum of 60 AMP at the Meter and 60 AMP at the Subpanel. Others have said 80AMP outside and 125AMP at the Subpanel.

Here is some background: It so tough to get insurance for a small Multifamily building in California due to all the Disaster we have had here in the state Lately. This build has been in our family for decades. Our insurance company is requiring us to upgrade our electrical. We currently have the old Federal Pacific Panels. And we have never had any issues. There is 1 Utility Drop to the Building, 6 Apartment Units with individual Meters and Panel with 30 AMPS Each that runs to a subpanel on the interior of each unit. And there is 1 Panel for the common area which is also 30AMP mainly for exterior lights and garage door openers. I figured that if I am being forced upgrade the Electrical, I might as well get as much value out of it as I can. And since the government is forcing us to transition our Natural Gas Appliances to Electrical. I might as well do that at the same time.

When I started doing research on the electrical appliances. I found out that these appliances need a lot of Amperage. Electric Water Heater = 75 AMP with 2 double pole breakers of the 40AMP each, Electric Stove = 50 AMP Double Pole, Dryer = 35 AMP, Center HVAC 30AMP. After doing the Load calculation for all the connections. I found out that if I wanted to Electrify everything in the each of the units. I would probably need about 150 AMP Subpanel for each Unit.

I went to the Planner for the local Utility and asked the for my options. They said that I have overhead Service and the Maximum they can provide is 400AMP Conductor rated at 80%. So technically only 320AMPs. Their tariff only allows them to have 1 Drop per location for the same Voltage. I could have a One phase Drop and a three-phase drop but I don’t even know what do with a 3 Phase. And I don’t want to burden my tenants with additional cost of paying commercial rates with a 3-Phase. The 2nd option he offered was to go underground. But that would mean that I would need to pay and put this huge transformer on my property with 3-ft clearance all around and 7-ft in front of it. That is impossible because I don’t have the money or the space for that. Last option was to have put a larger transformer on the Pole and run the lines underground. And Utility Planner came to do a Site Survey. He saw the electric pole that is located at the far corner of my property but the Space around it is super limited, and he thinks that it cannot handle more then 1 riser. Thus, he concluded that I will only be limited to a 400AMP (320AMP Actual) connected overhead.

So here is my Second Question. Suppose that in the future my Utility is forced to take all the lines underground, or give me a second drops, or can give me 600AMP to 800AMP conductor. What should I do with my current upgrade where I am limited to 400AMPs, so I can set myself up to save money on a future upgrade. Here is what I was considering: (a) Purchase Meter Modules that rated for high Amperage like 150A or Higher per Meter but for now only put an 60A to 80A Breaker in it due to the limit of the 400A Disconnect (b) Run #2 or #1 Wire to the Subpanels that is rated for 150A but for now put only an 80A to 100A main Breaker in it. (c) Run all the homeruns to the Electrical Appliances from the Subpanel but for now leave them idle/not connect them to a breaker nor provide the outlet. So, I don’t have to destroy any drywall in the future.

Would this mean that all I would need to do for a Future Upgrade is to just upgrade the Disconnect to 600A or 800A. Change the Meter Breakers to 125A or 150A. And Change the Main Breaker on the Subpanels to 125A or 150A and connect all the idle wires to breakers and put in the outlets. Does this plan have any merit?

 

[tortuga]

There is 1 Utility Drop to the Building, 6 Apartment Units with individual Meters and Panel with 30 AMPS Each that runs to a subpanel on the interior of each unit. And there is 1 Panel for the common area which is also 30AMP mainly for exterior lights and garage door openers.

Are you a C10 or a General B able to pull the electrical permit or are you planning to hire an electrical contractor to do this work?

I figured that if I am being forced upgrade the Electrical, I might as well get as much value out of it as I can. And since the government is forcing us to transition our Natural Gas Appliances to Electrical.

Before doing an expensive upgrade I would get some clarity on what precisely the insurance company is wanting. My understanding is the gas ban only applies to new construction and even that is tied up in court. There may be other reasons to consider replacing old gas appliances with electric though.

When I started doing research on the electrical appliances. I found out that these appliances need a lot of Amperage. Electric Water Heater = 75 AMP with 2 double pole breakers of the 40AMP each, Electric Stove = 50 AMP Double Pole, Dryer = 35 AMP, Center HVAC 30AMP. After doing the Load calculation for all the connections.

If you just want to upgrade the units with the option of eliminating gas you can run new 150A feeders and panels to each apartment, as long as 150A meets the minimum calculated load for each unit.
The service entrance and main breaker need to get sized based on the current load using a NEC load calculation, which a C10 or Electrical Engineer can do for you.
There are meterpacks that easily convert to underground from overhead.

 

[augie47]

On multiple units the Code takes into account the load diversity so it is not just sum of the loads on each unit. As tortuga suggests a qualified contractor or engineer can give you the options.
(there is pretty much universal agreement the FPE panels need to go)

 

[LA-Sean]

Are you a C10 or a General B able to pull the electrical permit or are you planning to hire an electrical contractor to do this work?

Before doing an expensive upgrade I would get some clarity on what precisely the insurance company is wanting. My understanding is the gas ban only applies to new construction and even that is tied up in court. There may be other reasons to consider replacing old gas appliances with electric though.


If you just want to upgrade the units with the option of eliminating gas you can run new 150A feeders and panels to each apartment, as long as 150A meets the minimum calculated load for each unit.
The service entrance and main breaker need to get sized based on the current load using a NEC load calculation, which a C10 or Electrical Engineer can do for you.
There are meterpacks that easily convert to underground from overhead.

Thanks Tortuga. I currently only hold a General B, C-20, and C-39. I aspire to get my C-10 in the Future. This is my family's building. I'm just trying to help my father in reducing his cost for the upgrade by perform as much of the work on our own and to set him up for success in the future. I have obtained quotes for Electrical Engineering from several Self-Employed and Electric Contractors, but nothing was less than $3,000 for the Engineering. My Father really doesn't want to spend that much. So, I have been doing a lot of the work on my Own. I created the Site Plan, Load Calculations, Home Run Schedule, and Panel Schedule just doing research and using the resources available online. Please these plans on YouTube at

. I'm currently at a stage where I have pulled the required Permits and Requested a Meter Spot from the Utility Planner. The Utility Planner has provided a Meter Spot but is hesitating to give me the full 400A Conductor. I have submitted my Site Plan, Load Calculations, Home Run Schedule, Panel Schedule based on full Electrification of the Building to him last week and am awaiting his response.

That being said. I am kind of at the end of my knowledge base. That is why I reached out her for help. I soon must start ordering Equipment because there is a long lead-time for the 400A Disconnect and Multi Gang Meter Panels. I just want to make sure that what my father invests in will give him long-term value. I want to order the right Equipment that is modular based (easily interchangeable) that meets my TODAY LIMITATION (400A) and my FUTURE NEED (800A). That I install now and will be upgradable at a low cost with few component changes as possible in the future. Basically, I have three Questions that I cannot get clear answers to:

1. What Appliances can I covert from Gas to Electrical [Stove (50A Double Pole); Clothing Dryer (30A), Water Heater(2 x 40A Double Pole)] with my limited 400A connection. By City Code and for good panel schedule organization, I am required to have the following Home runs: Center HVAC with Heat Pump (30A), Fridge (20A), Microwave/Kitchen Vent (20A), Dishwasher/Garbage Disposal (20A), 2 Kitchen GFCI for small appliances (20A Each), 1 Bath GFCI (20A), 1 Bedroom (20A), 1 Living Room (20A), Hallway/In-Unit Laundry (20A).
2. Keeping in mind the requirements provided in the first Queston. For a 400A Disconnect with 6 Apartment Meters (4 of them 1Bd/1Bt, 2 of them 2Bd/1Bt), 1 Common Area Meter with (2 Storage Room, 8 Lights, and 3 Garage Openers), and 3 Spare Meter Spaces for future development. (a) What is the Maximum Size of the Breaker I can put at the Meter for Each Apartment Unit, and (b) What is the Maximum Size Breaker I should put as the Main Breaker for the Sub-Panel (Suppose it is a 150A Sub-Panel). Where the Breakers will not get overloaded, or I will get constant calls from Tenants that the breaker keeps tripping.
3. What is the Right Equipment (Disconnect, Multi gang stack-able meter along with panels, and sub-panels) that is Modular, Compatible, and Easily available:
   1. Modular (Easily interchangeable parts) meaning that I can easily/cheaply upgrade from a 400a System to 800a System in the future by making like 3 adjustments: (i) The system allows to change the feed from overhead to underground; (ii) Change the Disconnect from 400A to 800A WITHOUT having to upgrade the Multi gang stack-able meter along with panels, and sub-panels; (iii) Change-out the Meter Breakers to a higher amperage.
   2. Compatible equipment meaning that the Disconnect, Main Panel, and Sub-Panel are compatible with each other and the Utility’s equipment. The Utility Planner has required me to provide a “EUSERC drawings for the panel before purchasing and installing the panel” because of the shortage of equipment supply in the market. He was saying that customers are ending up with equipment that is not compatible with each other and the Utility.
   3. Parts are easily available for repair and upgrades. Meaning that the Equipment is not discontinued when I go to upgrade in the future and parts for repair are easily available at like Home Depot/Lowes.

 

[tortuga]

I'm just trying to help my father in reducing his cost

In my experience having to do things twice (installing the wrong gear) is the most expensive way to do things, get some clarification on what the insurance co demands are.
Keep calling around until you find a C10 or engineer that is good with multi family calcs and will consult with you and help with your calculations for a more reasonable rate.
A few of the forum members here are in the LA area.
Since your heading for a C10 I recommend investing in a current codebook and taking some classes from our forums sponsor Mike Holt.

 

[LA-Sean]

In my experience having to do things twice (installing the wrong gear) is the most expensive way to do things, get some clarification on what the insurance co demands are.
Keep calling around until you find a C10 or engineer that is good with multi family calcs and will consult with you and help with your calculations for a more reasonable rate.
A few of the forum members here are in the LA area.
Since your heading for a C10 I recommend investing in a current codebook and taking some classes from our forums sponsor Mike Holt.

The Insurance demands that all the Federal Pacific Panels be replaced both the Main Panels and Sub-Panels. But seeing the cost/benefit analysis and for long-term sustainability it makes sense to rewire the building at the same time. I definitely agree with you on doing things twice. I hate that too. But my Utility isn't giving me much of a choice by restricting me to just 400A overhead. I figured, I can do I all the homeruns to a 150A Standard on the Interior of each Unit and Do the Home run from the Main Panel to the Subpanels at the same standard. And if the Utility ever decides to upgrade up to a higher Amperage or give us a second drop of 400A. We at least will not have to do any of the interior rewiring again.

I feel like I have done a lot of the leg work. If some here on the form can help me with the balance of the Calculations at reasonable cost or answer those 3 questions. I would love to hear from them.

Thank you for the recommendation on the Code Book and Classes. I will definitely do that after I complete this project.

 

[JoeStillman]

It wouldn't be a code violation to replace the Federal Pacific panels with new 150A panels and back-feed them from the original feeders. Then when California offers to buy you all new electric appliances and a new service, you can do the rest of the job. If you PM me I can share a spreadsheet that we use to compare Article 220 Part III to Part IV for multi-family services. It does both calcs at once and you can pick the lesser of the two. Depending on the appliances, Part IV usually takes the lead at about 30 dwelling units. I am not licensed in CA so I can't do the calc for you.