400A new home, configuration options/suggestions

[Miranda]

400A is new for me. I am here to learn what configuration options are available to me in the design of a new home. This will NOT be a DIY job. I will be hiring an electrician but want to better understand so I can spec it out the way I want it before I seek bids.

Loads include (3) heat pumps 7 tons total, (2) on demand water heaters, electric stove and wall ovens, electric dryer, (2) well pumps, swimming pool pump, pool heater (maybe), outdoor hot tub, indoor whirlpool tub, elevator, workshop including welder, dock with boat lift, 50A RV hookup.

Dock is 200' from house so needs dedicated subpanel. Pool circuits also on subpanel, most remaining circuits will be homerun.

Does 400A usually get split up into (2) 200A panels? Or is it feasible to have (1) 200A and (2) 100A panels feeding off the meter disconnect.

Lastly, would like to have the ability to connect a smallish generator to power circuits which may be on different subpanels....is there any way to do this? Would prefer to send power to the WHOLE system but choose to turn on just what I need at the time from ANY subpanel (for example, the well pump, refrigerators, ad a couple lighting circuits are essential, but I may choose to shut those down to run the boat lift briefly , or a water heater, microwave or electric dryer). We are in hurricane country and have discovered we may need EVERYTHING powered....but not at the same time.

 

[iwire]

400A is new for me. I am here to learn what configuration options are available to me in the design of a new home. This will NOT be a DIY job. I will be hiring an electrician but want to better understand so I can spec it out the way I want it before I seek bids.

I will just start out with that you need to keep in mind what is common practice in some areas may be unheard of or even prohibited in other areas.

Does 400A usually get split up into (2) 200A panels?

Often the least expensive option.

Or is it feasible to have (1) 200A and (2) 100A panels feeding off the meter disconnect.

You could but I would likely stick with two - 200 amp panels and run as many 100 amp subs from those as needed. It is the calculated load that matters not the amps totaled up from each breaker handle.

Lastly, would like to have the ability to connect a smallish generator to power circuits which may be on different subpanels....is there any way to do this?

Automatically no, that would become tricky and expensive.

If you stick with manual operation you can power up the entire house so that you can pick which loads you want to power at any given time.

 

[Miranda]

Absolutely, manual switching is my intention for the generator, and I don't mind switching breakers on and off as needed. I've never needed more than about 50A during an outage, but you never know WHICH 50A you're gonna need. For example, during an outage, if I need to evacuate by boat, I don't mind cutting off the fridges, pumps and water heaters to let the boat down from the lift. Likewise, if I need to dry some towels, I can shut down everything to run the dryer for a bit. At night I can run only the fans and fridges. I don't need it all at once, but I'd hate to have to choose which circuits have the capability of being switched.

 

[electricalist]

In the houses i worked on that had a generator there was usually a panel that had all the circuits and i dont know if it was so they could buy a smallish generator or something else,,even though they hardly get used here the home owner kept adding things,,,just in case...

 

[Miranda]

Absolutely, manual switching is my intention for the generator, and I don't mind switching breakers on and off as needed. I've never needed more than about 50A during an outage, but you never know WHICH 50A you're gonna need. For example, during an outage, if I need to evacuate by boat, I don't mind cutting off the fridges, pumps and water heaters to let the boat down from the lift. Likewise, if I need to dry some towels, I can shut down everything to run the dryer for a bit. At night I can run only the fans and fridges. I don't need it all at once, but I'd hate to have to choose which circuits have the capability of being switched.

 

[Miranda]

For the generator, it would definitely be manual transfer switch of some sort, no automatic needed. I have been through many hurricanes with a portable generator, and seldom need more than 3000W, the trouble is WHICH 3000 watts. I would like to find a way to safely, legally backfeed the whole service, even though I can only use select circuits for use at any given time. I don't mind rationing and switching off breakers as needed. My current home has a 50A manual transfer switch with a generator panel, which doesn't work out so well because many of the circuits on it I only need occasionally, and other circuits I need occasionally are not on it.

For example, during a storm, I need the fridges and water pump (to flush toilets) running most of the time. But if I need hot water for a bath, I can cut those off, and power only the HWH for 45 minutes to fill the tank. Likewise, if I need to evacuate by boat, I'd like the ability to cut everything else off and lower the boat lift....a one time thing not worthy of keeping the boat lift permanently on a generator panel. I may need to cut everything else off to run a load of towels through the dryer (hurricanes can be rathe wet). While I sleep, I power only the fridges and ceiling fans, but during the storm I may want to turn on a TV to get some weather news, or light up the barn for a few minutes to check on the animals. I don't mind the effort of shutting down other circuits to do this. As you can see, my needs are all over the place geographically...putting all those things on a 50A generator subpanel impairs daily operation. Getting a bigger generator isn't the answer, because during a storm fuel can be hard to come by. The smaller the generator the better

 

[mgookin]

Have you done a load calc yet to make sure the 400A is sufficient?

 

[electricalist]

The load calculation will also be helpfull for the generator sizing.
Try looking up load shedding. Which allow more things connected and using them as needed.

 

[Smart $]

...
Try looking up load shedding. Which allow more things connected and using them as needed.

Only pertinent when using an automatic transfer switch and generator.

 

[Smart $]

Everyone will point you to doing a load calculation... but for a non-electrician/engineer, there are quite a few nuances that you will not be familiar with enough to do one.

If you want some help 'guestimating', need living space floor area and nameplate electrical data from equipment (volts and amps, watts, or MCA; note 'tons' for A/C is not accurate enough).

 

[electricalist]

Oh, I thought it was when using a manual transfer switch. Automatic having to be able to supply the whole load

 

[Smart $]

Oh, I thought it was when using a manual transfer switch. Automatic having to be able to supply the whole load

You can do load shedding manually with manual transfer system, which is what the OP wants.

With an undersized generator (i.e. insufficient for whole load), load shedding would be required using an automatic transfer system.

 

[electrofelon]

Based on your descriptions and wants/needs, I would think a good option would be to have 2-200 panels. Install an interlock kit on one so you can back feed it with a generator and make that your emergency panel. On the other panel, just put your "big stuff" that you will never run like hot tub, AC/heat, large electric resistance things. Even a small generator can run all your lights and convenience outlets, so you would just need to manually be selective with things like the water heater. Better yet get a gas water heater.

 

[James L]

.....

Loads include...... (2) on demand water heaters



.... would like to have the ability to connect a smallish generator to power circuits which may be on different subpanels....is there any way to do this? Would prefer to send power to the WHOLE system but choose to turn on just what I need at the time from ANY subpanel (for example, a water heater...)

did anybody catch this part? Wanting to be able to turn on a tankless water heater (probably 120 amps) powered from a "smallish" generator?

I think advice to this guy ought to end

 

[ceb58]

did anybody catch this part? Wanting to be able to turn on a tankless water heater (probably 120 amps) powered from a "smallish" generator?

I think advice to this guy ought to end

Ever heard of a gas fired tankless?
Any way, to the OP it was said before but your situation and location will differ from others in various parts of the country. The best thing for you to do is chose 2-3 reputable, licensed and insured electrical contractors and sit down with them with the plans, tell them what you want and get bids. Just be prepared for sticker shock. With what you are wanting you will be well into the 25-30K range with out the generator.

 

[kwired]

did anybody catch this part? Wanting to be able to turn on a tankless water heater (probably 120 amps) powered from a "smallish" generator?

I think advice to this guy ought to end

I did, and has been pointed out they could be gas fired tankless heaters, but then so can the pool heater, or backup heat for the heat pumps - bottom line is depending on exactly what is there 400 amps may or may not be enough just for some of the major loads that have been mentioned - plus we still have a general lighting load and possibly a fixed appliance or two that maybe were not mentioned.

 

[James L]

....as has been pointed out they could be gas fired tankless heaters, but then so can the pool heater, or backup heat for the heat pumps......

Possible, but not too likely considering the "loads" he's grouped together with these two water heaters. And the pool heater (maybe)

400A is new for me.....

Loads include (3) heat pumps 7 tons total, (2) on demand water heaters, electric stove and wall ovens, electric dryer, (2) well pumps, swimming pool pump, pool heater (maybe), outdoor hot tub, indoor whirlpool tub, elevator, workshop including welder, dock with boat lift, 50A RV hookup.....

Maybe he'll have a steam engine powering his elevator?

 

[Miranda]

did anybody catch this part? Wanting to be able to turn on a tankless water heater (probably 120 amps) powered from a "smallish" generator?

I think advice to this guy ought to end

I agree, YOUR advice to me ought to end because you are just plain rude. There is always that one guy that has nothing better to do than pick apart somebody else's post looking for a way to criticize......

I have no intention of running a tankless water heater with a generator, didn't YOU catch the part where I said "power only the HWH for 45 minutes to fill the TANK". (regular water heater <30 amps) I will not be powering ANY of the big loads on that list with the generator.

In my current home, the only loads I need to run simultaneously are are the fridge/freezers, well pump, ceiling fans. I get by just fine most of the time with my 3000W Yamaha inverter, which will run quietly all night long on 3 gallons of gas. Occasionally, I will need to power a SINGLE 220V 30A load briefly, such as a TANKED water heater OR a boat lift OR a clothes dryer. When I need to do that I disconnect the Yamaha and connect a 7500W Generac for the duration of the need. It is very loud and guzzles gas. Seems like a hassle, but gasoline is very difficult to get after a storm, propane....impossible. I've had to go two weeks without refueling, so a "smallish" is not a cost cutting measure, it is a necessity. My neighbor was bragging about his 25kW whole house generator setup...till he ran out of propane a couple days into the first storm.

Sounds like an interlock kit on one 200A panel may be the best solution. I don't like the generator subpanel I have now because sometimes the one receptacle I really need that one time isn't on that panel, and you can't add everything to it.

 

[Smart $]

...

Sounds like an interlock kit on one 200A panel may be the best solution. I don't like the generator subpanel I have now because sometimes the one receptacle I really need that one time isn't on that panel, and you can't add everything to it.

If you want to keep all options open, install an interlock kit on both panels. Put your smallish (essential) loads on one panel, biggish (less-essential) loads on the other... generators to match.

 

[James L]

I agree, YOUR advice to me ought to end because you are just plain rude. There is always that one guy that has nothing better to do than pick apart somebody else's post looking for a way to criticize..
.

I don't believe I addressed you or offered you any advice. Simply noting to others what appeared to be very inconsistent info.