Service Entrance - 320A or 200A?

[thinair]

I'm at the point where I need to make some informed decisions and would like some informed answers. Hopefully I can ask the questions correctly.

I'm building a new garage with a small efficiency apartment above that will have an electric stove, microwave, refrigerator, and probable small gfa furnace to heat 500 sq. ft. up top. The garage will be heated with gas, most likely a Hot Dawg, the garage space being 600 sq. ft.

The current electrical is overhead and the power company said they cannot do undergound, I must stay with overhead.

The new garage is situated between the service pole and the house. The house has a new 200a service entrance and panel.

I will go overhead to the garage then underground to the house from the garage, the new service entrance/meter will be on the garage.

My desire would be to keep ample amperage going to the house as the house is being completely rehabed and added on to. The home finished sq. ft. will be 1,950 and two bedroom, three bath. Heat will be gas boiler radiant. Dryer will be electric, stove gas.

Can I have a 320a meter/service entrance at the garage being fed overhead, then run underground from that to the house, and through the garage wall for a panel in the garage? If so does that give me 120a at the garage panel and 200a at the house?

I probably need only 150a at the house and 100a at the garage.

I would like to run a small compressor, wire feed welder, and once in awhile a stick welder off the garage curcuit.

I do not need separate meters for garage and house.

Thanks in advance for your help.

 

[wssix99]

Do you ever envision having an electrical car or a hybrid that you would charge? If so, you'll need the extra juice in the garage. I recall some chargers can pull 80A.

We were looking at doing something similar for an old design for the house I am currently building. As I understand things, you don't need to split the service like between sub panels exactly.

You could have your main overhead go to a 320A disconnect that feeds two separate panels - one in the garage and one in the house. Both the house and garage could be 320A each. As long as the sum of both never exceeds 320A you are good. I think that you'll find that you can have any size panel in your garage (because its right by that disconnect) and that the size of your house panel will be limited on what you want to spend for buried wire going from the garage to the house.

For example, you could do a 320A service with a 200A panel in the house and a 200A panel in the garage. Fast forward to 2023 when you have two hybrid Ferrari's in the garage, pulling 80 A each at night on the chargers, you could pull 160A in the house before it would trip your service disconnect. During the day when you aren't charging your Ferraris in the garage, you could use the full 200A of the house panel without any limitations.

 

[sberry]

Ya, you plan on 2 electric Ferraris in your future? Wire just in case. Most mfgs now make a 200A with a main lug feed thru just for this.

 

[Mustang51js]

If it was me I would just run a 60 amp panel to apartment and 100 amp panel to garage off of existing 200 amp panel you have now. It's not like you will have everything on at the same time and if you did I still don't think it would trip the main.

 

[Mustang51js]

Or run a 125 amp to garage and off of that panel run 60 amps upstairs

 

[jeff000]

Fast forward to 2023 when you have two hybrid Ferrari's in the garage, pulling 80 A each at night on the chargers, you could pull 160A in the house before it would trip your service disconnect. During the day when you aren't charging your Ferraris in the garage, you could use the full 200A of the house panel without any limitations.

I haven't seen a residential charger larger than 30A (needing a 40A breaker), called level 2 chargers. Level 1 being a standard 15-r receptacle. It's the level 3 chargers that are 480/600v that can draw the 50-60-80 amps, although not many cars will accept the level 3 chargers.

I'd guess that 1% or less of the houses in NA have a larger service than 100a. And even though the average house doesn't really draw much more than a few amps a leg most of the day, they still would not be able to sustain an 80a charger. And having an Electric car cost an extra 2000-5000 dollars extra (depending on your area) for a service upgrade would be a burden most would not take.

That said, 200 amps would be lots for a pair of 80a chargers and running the house/apartment as normal. It would only limit the welding/compressor/shop use, but I doubt you would be welding between your pair of ferrari's.

A 200a panel at the garage and a 100 at the house would be fine with a 200a service. The house doesn't need any more than 100a, and only because 100a is the min service for a residence. And the garage/apartment isn't large enough to be a huge draw. You could bring a 60 or 40a sub panel off the main panel in the garage, but I don't really see the point personally.

Also, it's odd that the POCO says they won't run underground, most avoid overhead whenever possible. Ask them if they will go underground if you get the cable to the base of the pole.

 

[JoeFin]

Around here you don't get to dictate to the Utility (PG&E) what size service entrance you think you need. Sure you can run larger service feeders up the mast, but the utility is going to supply you with the service drop they think you need.

To get anything larger you need to submit engineered load calcs clearly demonstrating your specific needs

 

[thinair]

The overhead is now running from the alley behind the house 90' to the house directly. The garage will be built off the alley and in between the house and the pole. So the overhead is coming down anyway (looks and I'm replacing the sewer lateral anyway and adding water and nat gas in a ditch), so the new overhead will be going to the garage, then from the garage underground to the house. NorthWest Energy said they could do underground but it would be at a huge expense for me to do so. Overhead is free.

 

[thinair]

So... if I just wanted a 200a service to share with house and garage/apt. I could basically take the existing meter socket and panel and transfer it to the garage, and add a 100a panel at the house, with a disconnect outside on the house? The house will be 40' from the garage. The distance from the meter/panel at the garage to the panel in the house would be more like 90', hence I think I'll need a disconnect for code.

 

[James_B]

Our 3000 sq ft place in Newfoundland (3 bed/2.5bath) had a 200A service. Everything was electric, with a lot of baseboard heaters, 2 large refrigerators + chest freezer, large electric dryer. There was an unheated 2 car attached garage and a 1200 sq ft unheated basement. We tended to run the room thermostats a bit on the cool side at between 18-20deg C (64-68F). I was monitoring the house draw as at the time we were considering a 17kW full house backup generator. In mid-winter, the most I ever saw pulled out of the service were a few short term averages in the low 18kW region, so something like 160A average. It probably had some current surges that took the drain close to the 200A limit. Fortunately the 5HP compressor and welder weren't running at the time.

 

[Mustang51js]

Our 3000 sq ft place in Newfoundland (3 bed/2.5bath) had a 200A service. Everything was electric, with a lot of baseboard heaters, 2 large refrigerators + chest freezer, large electric dryer. There was an unheated 2 car attached garage and a 1200 sq ft unheated basement. We tended to run the room thermostats a bit on the cool side at between 18-20deg C (64-68F). I was monitoring the house draw as at the time we were considering a 17kW full house backup generator. In mid-winter, the most I ever saw pulled out of the service were a few short term averages in the low 18kW region, so something like 160A average. It probably had some current surges that took the drain close to the 200A limit. Fortunately the 5HP compressor and welder weren't running at the time.

18kw at 220volts is only 81 amps per phase so you still have plenty more.

 

[James_B]

18kw at 220volts is only 81 amps per phase so you still have plenty more.

I assumed a 200A service was 100 amps per 115V phase.

My background in electrical is from Australia (have an Australian 3 phase license), where the options are 240V single phase or 415V 3 phase. None of this silly North American 115V + 115V anti-phase stuff.

 

[thinair]

Good to have the comparison, I've been told by an old timer electrician in the area that 200a would be plenty for the house, garage, and guest quarters above the garage. My stove's will be gas, the heat is gas, the only thing electric is the dryer. But if the 320 meter/service entry is not much more than the 200a, I may go with it.

Still wish I could get an answer about how that 320 would work as far as splitting it up.

 

[Rich720]

Around here, the 320A meter bases can be had with 2 sets of load side lugs. The utility and inspectors will allow each set of lugs to feed a 200A panel. Very common for 1 feed to go to the house and the 2nd feed to go to the barn/shop etc.

Rich

 

[Mustang51js]

I assumed a 200A service was 100 amps per 115V phase.

My background in electrical is from Australia (have an Australian 3 phase license), where the options are 240V single phase or 415V 3 phase. None of this silly North American 115V + 115V anti-phase stuff.

Yeah you don't see to much 3 phase residential in the states. Some places are now 240 volts single phase so then it's only 75 amps per phase. I'm the opposite of you I don't know much about 3 phase and transformers and such since I rarely work with that stuff, 99% of my business is residential

 

[James_B]

Yeah you don't see to much 3 phase residential in the states. Some places are now 240 volts single phase so then it's only 75 amps per phase. I'm the opposite of you I don't know much about 3 phase and transformers and such since I rarely work with that stuff, 99% of my business is residential

I'm not an electrician. My background is aviation ground support electronics, but I needed a electrical license to legally work on some of our systems at work, and as some of our equipment is 3 phase, I needed that level of licensing ... and despite the licensing, I still couldn't legally work on the electrical wiring in my house, or even put a plug on a domestic electrical lead, unless that lead was connected to a piece of "communication equipment".

After talking to a lot of electricians in Canada (my step-son is currently doing an electrical apprenticeship in Newfoundland), I was quite surprised to see just how many had never dealt with a 3 phase system.

3 phase residential isn't common in Australia, but I know a few people that have it ... mostly to run big stuff in their workshop or occasionally a big airconditioning system. I had some friends that sold hot tubs and pools, and the enormous, high end "demonstrator" hot tub, installed behind their house, had 3 phase heating and pumps.

Occasionally you get some really strange residential setups in Australia. The house my grandparents bought in the mid 60s after my grandfather retired had a 2 phase feed. It was a tiny little beach house, but there were 2 separate 240V live to neutral feeds that were 120 degrees apart in phase, and the 415V available between the two phases was connected to the stove/oven only. The stove/oven wasn't anything special. Looked like any standard freestanding kitchen stove, but it required a 415V connection.

 

[Norcal]

In Germany, 400V 3Ø is common for electric ranges.

 

[wssix99]

I haven't seen a residential charger larger than 30A (needing a 40A breaker), called level 2 chargers. Level 1 being a standard 15-r receptacle. It's the level 3 chargers that are 480/600v that can draw the 50-60-80 amps, although not many cars will accept the level 3 chargers.

That's true for today, but I'm thinking in a future context; point being that the OP should think about their future electrical needs when putting in the service now.

Still wish I could get an answer about how that 320 would work as far as splitting it up.

The answer is above. You can choose whatever sizes that you want. The sum of the panel capacities can be greater than 320A, as long as you have a 320A disconnect feeding both of them.

 

[jeff000]

That's true for today, but I'm thinking in a future context; point being that the OP should think about their future electrical needs when putting in the service now.

True, think to the future, but 200a is still double 99% of the continent. And going to 320a you are going to incur significant cost increases for the cable and equipment that will never be utilized.

Banking on electric car chargers to require massive current seems like a silly thing to chase. Especially since everyone is looking at ways to use less and not more.

 

[wssix99]

True, think to the future, but 200a is still double 99% of the continent. And going to 320a you are going to incur significant cost increases for the cable and equipment that will never be utilized.

Banking on electric car chargers to require massive current seems like a silly thing to chase. Especially since everyone is looking at ways to use less and not more.

It may not even be an issue for the OP, but I'd throw it out there. Car charging (if there is more than one) can create some wicked peak loads.

Since the most remote panel will be in the house, the OP might be fine with a 200A service & disconnect with a 200A panel in the house and another 200A panel in the garage. (If there will be high peak loads in the garage.)

 

[thinair]

I checked into the cost of the 320, and with the pass through lug kit it's the better part of 2k not to mention the additional cable cost. I currently have a Seimens Combo panel for the outside meter/service entry. It has two area's for service disconnects, and currently the lower one is configed with breakers for 200a that moves on to my new 200a lug panel in the house. My thought now is to simply remove the current service entry and put it on the garage, and add a 100a breaker in the additional slot on the combo panel and run that to a 120a lug panel in the garage to service my garage needs and the apartment needs. Then run underground using 2/0 aluminum 4 conductor UFR to the house to a 200a disconnect where the combo used to be. Run copper from the disconnect to the existing home's 200a lug panel.

 

[nsula_country]

I did a 320A when I build my house in 2011. I did 100% of all electrical. The pole, meter base, (2) 200A feed thru panels, 500 MCM copper riser (10'), 2 100' something runs of quadplex to the house, 2 ground rods, (2) 70' runs of 2" conduit, (2) 4x6's and unistrut came in at about $1200 in materials alone. The reason I went 320A... All electric 2220 sq/ft house, two 27Kw tankless hot water heaters! 54Kw if both have to go wide open, which never happens. I have enough to service carport, pool, and chicken coop with no worries. Not to mention the (2) heat pumps (one with 15Kw, one with 10Kw heat strips for backup heat), double ovens, 5 burner cooktop, freezers, ect. No shortage of current. Minimal light blinking when a HVAC kick in. All this on a 50KVA transformer!!!

I am planning a shop build this year. Something like 40x60. I will put a 320A on it also. I may want a 10hp compressor or buy some 3 phase equipment and use a Roto-Phase_Converter. These are only about 2/3's efficient. Not to mention a 10 ton package heat pump to heat and cool... Thank goodness electric is cheap here!

CT

 

[kgc10]

I'm doing something similar for my new garage. I currently have a 10 year old 200amp meter main sub that feeds two sub panels. One panel is in the house and one is in the existing detached garage.

In the existing garage I have

240v
Air compressor
Lathe
Plasma cutter
100 amp Tig welder


120v
Normal stuff

My local utility is PG&E they give $3000 in credit when you upgrade you main panel. My current overhead service drop is feed from a pole in the back yard. So once I started building the new garage I wanted to eliminate the drop that goes over my back yard. I’m installing a 400amp panel or (320 amp continues) which falls under the upgrade language. After looking for a 400amp panel for a week I can tell you that I couldn't find what I wanted a semi flush overhead feed with a ringed meter main sub panel. I ended up with a surface mount underground meter main sub, with a conversion kit to be feed from overhead a second 200 amp breaker a gutter kit with 3" adaptor for $ 1200 . I priced it out $ 2500 to $ 1200 at Home Depot. So here is the plan I'm going to feed the house with 200 amps, existing garage with 60 amps, the new garage with 125 amps, and the Tig welder off the main panel. All my conduits are 2" pvc and 3/4 pvc in the slab to go from one side of the garage to the other.

BTW it was $5000 plus to go under ground I would be responsible to conduit to the pole with a box to splice in.