400 amp service -- what is required?

[eepete]

I also live in NC, and in 2006 built my house which has 400 amp service. As it was explained to me (so this probably had some pick and choose from the code for my situation):

If there was more than two feet of conduit between the meter base and the breaker panels, I had to have a 400 amp disconnect switch and then that switch would feed the breaker boxes.

In my case I also had a generator. So the configuration was the meter base, the disconnect switch, a panel before the transfer switch, the 200A disconnect for the generator, the generator transfer switch (400A switch), and then the wire went to 3 200A breaker boxes with a trough below them where each panel got its feed. The two disconnected switches had to be within 8 feet of each other.
I actually had conduit run from the meter base under the garage and then it came up in the basement where all the disconnects, switches and breaker panels lived.
The big honking cable that carries the 40A was something like $12 per foot- I had about $3500 of the stuff. Note also that this let me move the breaker boxes in the basement to a location that made the runs a lot easier to do than if I had the breaker panels right up against the outside of the house where the meter base was. The added complexity of the generator and panel box before the generator also brought about the need for all these extra boxes.
All in all, the total cost of "all this stuff"was about $9K. But for that price I have conveniently located panel boxes, the automatic generator transfer switch and the panel before the transfer switch so the generator size is more manageable. I've got a 45 KW generator. The 400A switch came about mostly because of the 3 heat pumps having 10KW resistive electric backup. Two of the three geothermal pumps have the 10KW strips on the panel before the generator.

Pete

[MossRoad]

I am kinda stunned that a house would need 400 amp service. We have 100 amp service and I arc weld, run a compressor, have modern appliances, etc... I can see going with 200 in a new house. But 400? Is this a farm or business, as well as the house?

Just curious, because when I priced out service for our future house, the difference between the 200 amp equipment and the next step up (300 something amp) was huge! And the monthly minimum fees for the next higher service over 200 amp was a lot more as well.

Again, just curious, not criticizing.

[roamerr]

I think eepete and tummu56 answered the question. My electrical contractor is running a 400 amp meter to a 400 amp disconnect switch (he described this as large) to (2) 200 amp 32 space panels. The panels are approx 30 feet from the meter box and 400 amp disconnect. The problem is that the garage is on the front (side entry) of the house and I do not want the underground electrical service or meter/disconnect on the side of the garage where everyone drives up to the house.

Looks like the distance warrants the 400 amp disconnect. He plans on mounting the (2) 200 amp panels on the wall surface in the garage so that the system has easy expandability. He is also surface mounting due to the house floor level being 5 feet above the garage floor. I will also have a generator hookup for the basics.

Guess this system was more complex then I realized. The positive is that I had the 400 amp service on my house specs so I'm not paying more. Looks like this one will cost the contractor more than I realized. He did mention that the 400 amp cable is currently around $12 a ft! Not much change there since year 2006.


As for why 200amp? I specified that all interior outlets be true 20Amp capacity. I do not want breakers flipping due to my girls hair dryers. Also the house is in the country and is all electric -- approx 3000 sq ft. The heatpumps take some power but the heat strips are power hogs when they come on for a few minutes. Also I have a 30 amp RV plug and wanted the ability to go to 50amp if desired later. Basically the house will rarely pull over 200 amp but will at times. The 400amp service was needed since I do not want the breakers flipping on Christmas day when the turkey is cooking, the microwave is running, the christmas lights are on, the heat pump heat strips kick in on both units, the 1hp well pump is running, and my girls are trying to dry their hair while the RV is pulled up next to the house so I can accomodate extra relatives...

[turbo36]

Talk to your electrician about the difference between "connected" load and "actual" load, most likely you do not need a 400 amp service. Keep in mind this is 400 amps at 220 volts (9.6Kw) so that is equivalent to 800 amps at 110 volts! I built a new house with two 42 space panelson a 200 amp service to do exactly what you want, all 20 amp circuits and and lots of dedicated circuits, one panel fed the other. When we hooked up the whole house generator I had to perform a break in procedure where I slowly increased the load to the maximum capacity of 66 amps at 220 volts. I had every light in the house on, both electric ovens , 3 hp well pump, 10 hp air compressor and portable electric heaters borrowed from my neighbors before we got to 66 amps.

[roamerr]

After laying out the house the electrician did mention that a 200 amp service would not have been adequate. If I had chosen Propane or Oil heat then 200 amp likely would have been fine. Using Electric Heat Strips (When Heat Pumps defrost or can not provide enough heat) really use lots of power...

[brin]

I have 400 AMP service to my house and 3 boxes inside and 2 outside..one box has the 2 big swithces you mention plus I have a switch to enable my standby generator and then the other outside box has the meter on it. We are about 200 feet from the transformer if that helps..it was pricey when installed 4 yrs. ago when we built our house.

[Jeepnford]

When I built my shop I moved up to a 400 amp service. The buried leads from the transformer to the house were already(thankfully) large enough. But I did need a 400 A meter base and a 2 cutoff switches,one for house and one for shop. I know this isn't exactly what you're doing but electrical can get expensive rapidly.

[ultrarunner]

Originally Posted by MossRoad

I am kinda stunned that a house would need 400 amp service. We have 100 amp service and I arc weld, run a compressor, have modern appliances, etc... I can see going with 200 in a new house. But 400? Is this a farm or business, as well as the house?

Just curious, because when I priced out service for our future house, the difference between the 200 amp equipment and the next step up (300 something amp) was huge! And the monthly minimum fees for the next higher service over 200 amp was a lot more as well.

Again, just curious, not criticizing.

None of the homes I've worked on here in CA have this kind of service either.... I have a welder, electric range, older large Air compressor and never had a single issue with my 100 amp service....

I still own my first home where the service is a single 30 Amp Edison Base Fuse from 1922 and the "Panel" consists of one 15 amp light circuit and one 20 amp outlet circuit... never had a problem in this 1150 square ft home...

Could be because in my area of CA it is customary to used gas appliances?

[roamerr]

Fo me to have gas I would have needed a large propane tank and refills. The only propane I will have is gas logs and they will run off simple 100 lb tanks since we rarely will burn them.

[theboman]

I see many new large homes with 200 amp service and when you see the box it's full, or maybe one empty breaker slot. Most homes will never, ever need more than 200 amp, you don't run AC and Heat at the same time and those are the biggest users.

I'm not sure how they are wired but I've seen many house with two 200 amp boxes, or a 200 amp box with smaller panel.

I know how to plug in an extension cord and replace bad bulbs, well, not much more, so there's how I know so much! Electric scares the s--t out of me! ah, I can handle a 9v battery with ease just don't put one in your pocket with keys, change...!