I ran across this site accidentally today and found someone who had many of the same issues I need help with. Most of my questions were answered reading the forum however I have one more, using the following information I am hoping someone can help.

The existing house is apx. 2300 sq ft w/a 200 amp service. I am adding an additional 1800 which will include the following: 1 bed room, 1 full bath w/a Jacuzzi and a steam shower, a gym and a 900 sq/ft garage/workshop which will have several power tools including compressor Additionally there will be a 3 ton HVAC (heat and air are electric)

In the existing house has a 200 amp breaker panel box wired back to back to the meter with only 70% of the slots used. The meter is now inside and needs to be outside. Additionally, I was going to put a 125 amp panel box in the addition but I got a like new 200 amp panel with all the breakers for $25 so I am using it in the addition.

I have pre wired ready to attach to the locations with 3 - 3/0 & 1 - 2/0 copper in conduit (from the existing meter to the new meter location) & (from the new meter location to the existing panel and to the new panel)

I had used a square D combo box with a 200 amp breaker and the meter all in one. However due to its construction I cannot put duplex lugs on the down side of the box. Additionally with the 2 breaker panels rated at 200 amps @ I now need a 400 amp breaker.

I need help finding either a combo box with a 400 amp breaker, or suggestions on how to re fit the exterior panels and where to locate them (for a good price, smile)

Thanks, MJ

You will need a lot more than just a 400 Amp breaker. The meter socket, and the incoming service entrance conductors will need to be all rated for 400 Amp.

I have never seen, and doubt a 400 "combo" panel exists, since 400 amp service is much more that just a 42 circuit panel.

Here is a link to a meter with 2- 200 Amp subfeed breakers, but still need two circuit breaker panelboards. Before you begin changing any meter, you must check with your electric utility for the metering equipment they allow.

http://www.milbankmfg.com/Products/C...#U5059-X-2/200

Sounds like you may be in for a rude awakening if you already wired for a new panel without planning how to feed it. You now need a new complete 400 Amp service.

Just off the top of my head, a 200A service requires a 2" mast; a 400A service requires a 4" mast.

I wouldn't look at increasing the supply. Heck, your not even adding a kitchen or laundry!

Keep the existing panel and add a 125A subpanel.

This is exactly what I am needing and looking for... however this lists for $2,791.86. Seems that anything rated at 320Amps is automatically expensive. The metal they use in these panels must come from the lunar surface.:o

The higher amperage equipment is handling a great deal of power, and must withstand the forces expected of it. Also note this unit, and all other meters, are rated 600 volt. There are too many voltages to make one for each voltage, so one size fits all.

Pay no attention to any "list" price. These prices are published by the manufacturers to throw off the other manufacturers, very competitive business. I would expect to pay approx. $800 wholesale for this unit, and from a vendor I purchase agreat deal from. If I was buying other equipment, such as panels, breakers, etc. the unit price may get down to $500 or so.

You would need to purchase such a unit from an electrical supply house, one that sells to the public, and not just to contractors. However, don't expect to pay wholesale.

There is no rhyme or reason to prices for electrical equipment.

However this and all UL Listed equipment will serve you a long time troublefree, with the proper care and maintenance. Isn't this peace of mind worth the safety of your home and loved ones?

Sure that's worth a lot but the higher price expected for higher amperage products seems to be more influenced by supply and demand then a UL listing... or even materials used.

Glad to hear that those prices are way off!

Thanks for all the information its helping me with determining which direction to go. However one of the comments got me thinking I may be over amping everything. Is there a place I could find the formula for determing the size of the panel I really need. I know that you have to add up all the possiable usage but I was hoping there was a chart somewhere to assist with the calculations?

In the code there is a minimal size for a kitchen and then an adder for sq. feet of living space.

In all my 20 years of experience, I have yet to see a 400A service in a single dwelling unit that does not operate a business. Just a thought!

There is no chart that lists amperage sizes for services. If this is in the USA, must use one of the optional methods as listed in the effective National Electric Code edition of your area.

I never show how to do the calcs here, too many variables to list and explain each variable. I suggest anyone that wants, can review the Examples shown in any NEC code book available at your local library. You will find very little available of the actual Code on the Internet. The material is seriously copyright protected.

The Examples show clear methods of interpreting the text of the many Codes , written in difficult to follow language,requirements for the various loads and circuits.

Briefly, general lighting is added at 3 watts per Sq ft of all livable space, add the watt load of required applicance circuits, heavy appliances, heating , air conditioning, apply derating factors to certain loads, add certain loads at 100%, to arrive at a total connected load in watts and amps.

These calculations are mandatory to size every service installed, new or replacement.

Having over 30 years of experience working in the Gold Coast of Connecticut, had the opportunity to wire over 20 or so affluent homes, and not all mansions, with 400 AMP services. Only one mansion had a 600 Amp I can remember.

And with all the toys , like hot tubs, steam generators, tennis court lighting, etc. these services get well used.

Oh, and thanks to the demand of China and other bursting economies, metals, esp. copper and steel, prices have increased beyond belief, adding to high costs of all electrical equipment in the last year. Over 82 % increase first half of 2006. Several posts here have mentioned this.

Not sure if this is exactly what one might need for this install but to me it looks right.

Seems to be a 400Amp meter panel with double lugs. This is what I need but unfortunately this one is overhead service and I need under-ground. However this is $9.99 plus shipping. Seems like a good deal if it is what you need.

http://cgi.ebay.com/New-Anchor-Elect...QQcmdZViewItem