dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
28033
share rss forum feed


Toddus

@verizon.net

400 amp single phase service wire size residential

I am building a new home 4,900 sq ft I was told I need a 400 amp service. I would like to find out what size feeder wire is needed from panel to meter, from meter to to riser. This is a single family dwelling.
60 amp sub shop
50 amp spa
30 amp water heater
HVAC
Range
whirlpool bath
5 bedrooms, basement, 3 bath
Kitchen
Is 400 amps necessary ? if so What would the wire feeder size need to be? I looked in my NEC it's been years since I've used one and found the AWG to be 600 for 420 amps did not seem right,am I looking in the right place?, any help would be appreciated.


Mr Matt

join:2008-01-29
Eustis, FL
kudos:1
Reviews:
·Millenicom
·Embarq Now Centu..
·Comcast
·CenturyLink
Here in Florida depending on the electrician and electric company the electrician will probably install a split 200 Amp service with two 200 Amp Panels.

Wire Size: »wiki.answers.com/Q/What_size_wir···mp_panel


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to Toddus
Ask the person who told you that you need 400 amps. They must have a reason for saying that.

Also, consult with your local utility. They can suggest some options.
--
The Truth is the foremost enemy of the State now.


Jahntassa
What, I can have feathers
Premium
join:2006-04-14
Conway, SC
kudos:4

1 edit
reply to Toddus
For that many square feet, I would think 400A would be on-par with heating / cooling and other needs, especially if everything you stated there is electric.

I don't recall what size wiring they used on my 400A install, but it's definitely pretty thick.


SparkChaser
Premium
join:2000-06-06
Downingtown, PA
kudos:4
reply to Toddus
I assume you hired an electrician to plan the home for you. Don't you trust his/her opinion?

toddus

join:2010-10-28
Concrete, WA
No electrician hired to give load calcs, all done over phone by sq ft,


wilbilt
Pronto Resurrected
Premium
join:2004-01-11
Oroville, CA
reply to Toddus
What do you plan for the shop? A 60A sub seems small given modern trends (welders, compressors, lifts, plasma cutters, etc...)
--
We were taking a vote when the ground came up and hit us.


nunya
LXI 483
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms

2 recommendations

reply to Toddus
Your electrician or architect / engineer should must do a load calculation. Due to single phase transformer sizes, most utilities really offer 320A service, not 400A.

This isn't something you take a chance on or get advice from an internet site. Hire someone who knows what they are doing.

65349376

join:2010-10-26
reply to Toddus
No electrician to do load calculations ??
I guess you didn't have a plumper either, how about HVAC, structure ?


macsierra8
Baby Newfoundland
Premium
join:2003-11-30
Minden, NV
reply to Toddus
Both Seimens and Square D 400 amp meter panels sold here are split 200 amp services with a supplied breaker for each as Mr. Matt said.

I ran 200 amp to my shop with 4/0 copper because of the 175' length. The other 200 was split between two sub panels in the house and the garage.
--
I was against Obama before it was cool!
Elect anyone BUTT Harry Reid!

Mr Matt

join:2008-01-29
Eustis, FL
kudos:1
Reviews:
·Millenicom
·Embarq Now Centu..
·Comcast
·CenturyLink
reply to Toddus
I failed to mention that some time ago I had a conversation with the manager of an electrical subcontracting company. I asked him why I had not seen 400 Amp service panels in residential applications. His answer was that the conduit size required to accommodate conductors for a 400 Amp service were so large that it would not fit between normal 2X4 Studs and the cost of one 400 Amp distribution panel was much higher than two 200 Amp Panels. At that subdivision, at each residence, the electrical contractor installed one rain tight combination 400 Amp Panel and Meter Can outside with two 200 Amp breakers each feeding two 200 Amp distribution panels via separate conduits.


macsierra8
Baby Newfoundland
Premium
join:2003-11-30
Minden, NV
reply to Toddus
Couple things about the 400 amp panel in residential applications planners aren't used to.

I had to modify the plans after approval from a 6 inch wall to a 10 inch wall to accommodate the 400 amp panel for the short distance I needed to mount the panel. Both the architect and county plan check missed that we needed a " firewall around and behind the panel because of the living area upstairs. As the panel by itself is 6 inch wide as the conduit template width shows. That plus some insulation required the 10 inch wall, couple of picts below.




--
I was against Obama before it was cool!
Elect anyone BUTT Harry Reid!


whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
kudos:9

1 recommendation

reply to Toddus
Over the phone? Taking someone's word for it based on a brief phone conversation, is not very wise.

As said by nunya, you MUST have an engineer, electrician (or qualified architect) perform load calculations. Since you will pay for this, make sure you tell them you want a copy of the calculations. Then you can post it here for us to check if you like. Considering that you have the money to build a brand new 4900 square foot home, then I am sure that would not be a problem. Likewise, I am sure you could get a copy of the plans before you spend a million $ plus. These should include the full electrical plans with load calculations. I know if I had the money to lay out to build a MacMansion (or really, a mansion in this case), I probably would not worry so much whether I needed a 400A service or not, and leave that to the professionals I hired.

Based on the size of the home, you will at least need a 200A service, that is for sure. And with 4900 square feet and some of the apliances you listed, they are likely right that you do need a 400A service. So, what is the problem? Are you planning on running the electrical yourself? If you don't know how to do the feeder calculations (not to mention the required load calculations) I suggest you step back and hire a professional. Since you are interested, take a look at table 310.15.(B)(6), which shows that the minimum is 400 kcmil copper wire for the service wiring.

themagicone

join:2003-08-13
Osseo, MN

1 edit
reply to macsierra8
said by macsierra8:

Both Seimens and Square D 400 amp meter panels sold here are split 200 amp services with a supplied breaker for each as Mr. Matt said.

I ran 200 amp to my shop with 4/0 copper because of the 175' length. The other 200 was split between two sub panels in the house and the garage.
Must of been before copper was almost expensive as gold. For the 200amp service at the house I was working on I used 4/0-4/0-2/0 AL Feeder and then a 4/0-4/0-4/0 to main panel from meter.

42 NEC 310-15 CONDUCTOR SIZES FOR 120/240
VOLT 3-WIRE, SINGLE-PHASE,
DWELLING SERVICES AND FEEDERS
Copper Aluminum Service Rating
4 AWG 2 AWG 100 amps
1 AWG 2/0 150 amps
2/0 4/0 200 amps
400 kcmil 600 kcmil 400 amps

Speedy Petey

join:2008-01-19

1 recommendation

reply to whizkid3
said by whizkid3:

Over the phone? Taking someone's word for it based on a brief phone conversation, is not very wise.

As said by nunya, you MUST have an engineer, electrician (or qualified architect) perform load calculations. Since you will pay for this, make sure you tell them you want a copy of the calculations. Then you can post it here for us to check if you like. Considering that you have the money to build a brand new 4900 square foot home, then I am sure that would not be a problem. Likewise, I am sure you could get a copy of the plans before you spend a million $ plus. These should include the full electrical plans with load calculations. I know if I had the money to lay out to build a MacMansion (or really, a mansion in this case), I probably would not worry so much whether I needed a 400A service or not, and leave that to the professionals I hired.

Based on the size of the home, you will at least need a 200A service, that is for sure. And with 4900 square feet and some of the apliances you listed, they are likely right that you do need a 400A service. So, what is the problem? Are you planning on running the electrical yourself? If you don't know how to do the feeder calculations (not to mention the required load calculations) I suggest you step back and hire a professional. Since you are interested, take a look at table 310.15.(B)(6), which shows that the minimum is 400 kcmil copper wire for the service wiring.
I could NOT have said this better myself.


nunya
LXI 483
Premium,MVM
join:2000-12-23
O Fallon, MO
kudos:12
Reviews:
·Charter
·voip.ms
reply to macsierra8
I'm curious about the (I assume Sch 80) conduits coming up in the midst of the foundation. I've never seen this before. Only inside or outside.
Was it done for security or some other reason?
What does the finished product look like? What happens if you need to replace your service equipment?


macsierra8
Baby Newfoundland
Premium
join:2003-11-30
Minden, NV

1 edit
reply to themagicone
said by themagicone:

said by macsierra8:

Both Seimens and Square D 400 amp meter panels sold here are split 200 amp services with a supplied breaker for each as Mr. Matt said.

I ran 200 amp to my shop with 4/0 copper because of the 175' length. The other 200 was split between two sub panels in the house and the garage.
Must of been before copper was almost expensive as gold. For the 200amp service at the house I was working on I used 4/0-4/0-2/0 AL Feeder and then a 4/0-4/0-4/0 to main panel from meter.

42 NEC 310-15 CONDUCTOR SIZES FOR 120/240
VOLT 3-WIRE, SINGLE-PHASE,
DWELLING SERVICES AND FEEDERS
Copper Aluminum Service Rating
4 AWG 2 AWG 100 amps
1 AWG 2/0 150 amps
2/0 4/0 200 amps
400 kcmil 600 kcmil 400 amps
Yep, the 4/0 thhn copper is gold now days.. I surf on E-Bay a lot and have found some great deals on wire and stuff. I've bought trucks, forklifts and scissor lifts, you name it.

The deal on the copper was that a company finishing a big runway job had a 1000' roll left over and he put it on E-Bay for 1000 bucks plus freight at buy it now. I almost broke my finger hitting the keyboard..

I'v since bought some 3/0 copper thhn from the same guy and I watch his auctions close. But now with scrap prices being so high those copper thhn deals are hard to find.

I need the full 200 amps for my shop as the plasma cutter needs 100 amps, and the industrial air compressor needs 50 more and the roto phase 7.5 hp needs 30-40 or so, lighting and saws etc etc..
--
I was against Obama before it was cool!
Elect anyone BUTT Harry Reid!


macsierra8
Baby Newfoundland
Premium
join:2003-11-30
Minden, NV
reply to nunya
said by nunya:

I'm curious about the (I assume Sch 80) conduits coming up in the midst of the foundation. I've never seen this before. Only inside or outside.
Was it done for security or some other reason?
What does the finished product look like? What happens if you need to replace your service equipment?
All are sch 80, yes. We do our custom homes like that and especially in the higher snow country around Lake Tahoe. Although there is no code that sez you have to, long as you use sch 80 above ground.

That little room under the stairs and deck is more for sheer load as the structure is 35 feet high and the engineer wanted it so I put it to use and gained some floor space. We have a wind rating here much like Florida with 120 mph wind load + snow load.



--
I was against Obama before it was cool!
Elect anyone BUTT Harry Reid!

garys_2k
Premium
join:2004-05-07
Farmington, MI
reply to Toddus
OMG! Don't even think of making this a DIY job, leave one this big to the pros, please. No way I'd want to take on a full house's feeder calculations and I'm a P.E. -- I'd leave that to someone who specializes in those things.


whizkid3
Premium,MVM
join:2002-02-21
Queens, NY
kudos:9

1 edit
reply to nunya
said by nunya:

I'm curious about the (I assume Sch 80) conduits coming up in the midst of the foundation. I've never seen this before. Only inside or outside.
Was it done for security or some other reason?
What does the finished product look like? What happens if you need to replace your service equipment?
It is interesting. We run many conduits through slabs, but not foundations or wall footings. We use concrete encased PVC below the slab, transitioning to rigid galvanized steel for elbows and where it comes up through the slab. I assume structural issues have been checked?