400 amp residential service

Status
Not open for further replies.
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
laketime said:
Yeah that is what I was thinking. A 400 amp main, double lug 3/0's to two separate 200 amp load centers with a main breaker.
Click to expand...
Actually what I do is use two 8 cir with main breaker and feed thru lugs on the outside of the house and then two 40 cir ml panels inside.

The outside panels allow me to feed a/c's, pools, separate structures etc from it and the inside panels carry the rest of the loads inside.

Others use a 400 amp meter main panel. It comes wired with 2- 200 amp breakers for the load to the inside panels.
 
O

One-eyed Jack

Senior Member
Location
Scotland Neck, NC
360Youth said:
I don't think you do. The SE conductors are sized by load, not a 200 amp OCP requirement. Only the feeders are affected by the '08 change. Correct?
Click to expand...

That is my take on it also. Do a load cal. for each sub-panel and size breaker and ser cable based on 60 degree rating. When the GC see's two 150's he is going to raise eyebrows and say where my 400 amp service.:D
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
There has been a long standing misconception that T. 310.15(B)(6) was valid for any feeder in a dwelling. There are areas that still allow the use of this table to sub panels without the entire load. It is probably not a real issue with residential loads but it is not the purpose of that table.

This table is for resi. feeders that carry the entire load of the house and for service conductors up to 400 amp with a single set of service conductors. In other words two 200 amp panels do not get the benefit that a straight 400 amp panel would get under T. 310.15(B)(6)

Also, in '08 we got thrown a curve ball with seu and ser being rated 60C in most cases.
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
360Youth said:
I don't think you do. The SE conductors are sized by load, not a 200 amp OCP requirement. Only the feeders are affected by the '08 change. Correct?
Click to expand...


If your calculated load came in at 176 amps, for instance, then 4/0 al would do it, but then you have to think about what Dennis, 4/0 AL SE 60 degree chart puts you down to 150
 
R

rodneee

Senior Member
laketime said:
So basically get a 400 amp meter and feed two separate 200 amp load centers off the meter?
Click to expand...

we have installed hundreds over the years and have found the two panel method is much cheaper and easier to work with....years back we also found out that while we were selling it as a 400 amp service using a "non -CT" meter the local power company was only set up 320 amp to its residential customers...
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
rodneee said:
we have installed hundreds over the years and have found the two panel method is much cheaper and easier to work with....years back we also found out that while we were selling it as a 400 amp service using a "non -CT" meter the local power company was only set up 320 amp to its residential customers...
Click to expand...

Okay, this is another concept that is often misunderstood. A 200 amp meter base is rated 200 amps for a non continuous load. However it is only rated 80% of 200 or 160 amps for continuous loads.

A 400 non ct meter base is rated the same-- 400 for non continuous and 320 for continuous loads. For some reason they market the 400 amp base as a 320 instead of marketing it the same as they do for a 200 amp base. It is down right silly, IMO.

The point is the poco is supplying 400 amps to that base and only 320 continuous load. Hope this helps.
 
I

IrishRugger

Senior Member
rodneee said:
we have installed hundreds over the years and have found the two panel method is much cheaper and easier to work with....years back we also found out that while we were selling it as a 400 amp service using a "non -CT" meter the local power company was only set up 320 amp to its residential customers...
Click to expand...

rodneee has the right idea, that is the most pratical way to go, when I do an install like this I use 3/0 copper THHN to feed each panel and run them in PVC.
It seems to work the best for me. Fitting a PVC raceway system is not difficult and it looks nice. since I work exclusively by myself running from the basement, upstairs to the outside and back down to pull service conductors makes for a good cardio work out. If I did a 400 amp service everyday for three months like this I wouldn't have to stretch out my rugby shirts in order to fit in them comfortably.
 
2

220/221

Senior Member
Location
AZ
This is how we do it here.

400 amp all in one is about $600. It has a 200A main breakered 40 space panel and a 200A main breaker for another panel.

The second main breaker is not installet yet in this pic.

electrical024-1.jpg


I don't have a pic but, the other method we use is a 400A meter/main that contains the meter socket and two 200A pullout disconnects. We then run our cable or conduit to the two 200A panels.

The meter/main can is locally manufactured, larger than the one pictured and cost about the same.
 
I

IrishRugger

Senior Member
220/221 said:
This is how we do it here.

400 amp all in one is about $600. It has a 200A main breakered 40 space panel and a 200A main breaker for another panel.

The second main breaker is not installet yet in this pic.

electrical024-1.jpg


I don't have a pic but, the other method we use is a 400A meter/main that contains the meter socket and two 200A pullout disconnects. We then run our cable or conduit to the two 200A panels.

The meter/main can is locally manufactured, larger than the one pictured and cost about the same.
Click to expand...

Are you holding the camera crooked or is that just how you guts mount stuff?
Just kidding that looks pretty cool I can think of some Agricultural and commercial storage application that this equiptment would work well in.
 
2

220/221

Senior Member
Location
AZ
My right leg is about 3" shorter than my left.

I'm a little self conscious about it so thanks for pointing it out.

























:D
 
mcclary's electrical

mcclary's electrical

Senior Member
Location
VA
IrishRugger said:
Are you holding the camera crooked or is that just how you guts mount stuff?
Just kidding that looks pretty cool I can think of some Agricultural and commercial storage application that this equiptment would work well in.
Click to expand...



I can get (2) value packs for about 100 bucks a piece, and a free meter base. Plus you still have to buy a panel for inside
 
Status
Not open for further replies.
Top