- Location
- Massachusetts
400 amp service(320) voltage drop
- Thread starter Trouyano
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
This would be related to 215.2(A)(1)Exception as well as other code sections.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Read the info inside the 400 amp meter base. If you go to the supply house around here and ask for a 400 amp meter base they hand you one that states 320 amps. Now why they sell the 400 amp base at the 320 rating and the 200 at the 200 amp rating instead of 160 amps rating- I don't know.
Not sure how the 3 phase meters are rated. Certainly in a home you would rarely be close to 160 amps continuous on a 200 amp service.
Not sure how the 3 phase meters are rated. Certainly in a home you would rarely be close to 160 amps continuous on a 200 amp service.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I just find the use of the term 400(320) to be confusing and I'm wondering why it's even noted that way. A 400 amp load calculation means a 400 amp meter enclosure.
- Location
- Massachusetts
An NEC 400 amp calculated load means you could use a 320/400 meter enclosure.
I don't know why the meter sockets are rated that way they just are.
They are called class 320 meters.
http://www.cooperindustries.com/con...ing_equipment/ring-type_metering/Class320.pdf
I have to ask if the 400 amp service is truly a 400 amp service, or a 320 when it is installed. A true 400 amp service will take a K base or some transformer rated metering. an S Base is only rated for 320 continuous.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
When I install a 200 amp meter base I understand that is only rated 160 continuous. It is still, IMO a 200 amp service. If someone has need of 200 amp continuous then I would go up to 400 amps or possible 300 amps
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I agree it's a 200 amp service, unless I'm missing something the use of the wording 160 amps continuous is irrelevant.
- Location
- Massachusetts
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Not really. It is relevant if you have over 160 amps of continuous load in the building. Basically the meter is not rated to carry a continuous load over 160 amps.
It may be unlikely scenario but that would be when it comes into play--
- Location
- New Jersey
- Occupation
- Journeyman Electrician
That makes a little more sense. If I had service equipment that was 100% continuous rated then the meter would need to be also if it were operating near it's maximum ampacity.
- Location
- Massachusetts
In that case the NEC load calculations would have required more than a 200 amp service.
I disagree. A class 200 meter is rated at 200 amps continuous, the class 320 is rated at 320 continuous. The meterbases I get(250 amp) are also rated at 200 amps continuous, although I have seen some of the mobile home combo panels(200 amp) rated at 160 continuous.
Last edited:
A/A Fuel GTX
Senior Member
- Location
- WI & AZ
- Occupation
- Electrician
So where is the meter, on the pole or on the house? Are you dealing with the service entrance conductors on the line side of the meter or the load side? In my area, the POCO feeds the line side. If that was your case, and the meter was on the house, you could double lug the load side service entrance conductors and run a set of 4/0 AL or 2/0 CU conductors to each panel.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Yes that's my point. The 200 amp meter would not be good in that case even though the load is under 200 amps
- Location
- Massachusetts
I am very confused,:? the load would not be under 200 amps it would be over 200 amps.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I am saying if the load is continuous at 170 amps and you had a 200 amp breaker that is rated 100% then you could not use the 200 amp base. Highly unlikely I know
We do have a member saying that the 200 amp base is rated 200 amps continuous. I will have to check as it was not always that way.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I just checked a new Milbank 200 amp meter base and it is indeed rated 200 amps continuous so everything is moot about this issue. It now makes sense that a 200 and a 320 base is rated at the continuous loads. I should have checked but I wonder if the 200 amp base is rated 250 amps non continuous
Would that be me?
Actually I am saying a 250 amp base is rated 200 amps continuous.Here is one from the home depot;
http://www.homedepot.com/p/Siemens-...er-Socket-SUAT317-0PGP/100187344#.UZqMCU3D_IU
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- Status