Can someone help me understand this new 320 Amp continuous/400 Amp Max single position meter socket? How do you size the conductors - 320 Amps continuous or 400? Can you use a 350 Amp service disconnect or must it be 400? I'm a little confused over the application niche for this product. Thanks.
320 Amp Single Position Meter Socket
- Thread starter johnuia
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Re: 320 Amp Single Position Meter Socket
It's great for resi services where a 40 space panel (200A) is not quite big enough. You can put 2 panels next to each other and run both service entrance conductors to the load lugs of the meter pedestal. The lugs are rated for 2 conductors!
I commercial work same situation applies. "Generally" a 200 Amp panel isn't loaded up to 200A, for obvious reasons. If you can load it to 160 and have the other panel loaded at 160 the 320 meter socket pedestal works great.
You can size your conductors at 3/0 for each 200Amp panel. You could even install 2-100Amp panels and install #3 to each.
If I was going to use a single main, I would probably use a 400A switch and use the fuses for the calculated load. edit Not to exceed 320
edit:
Just checked specs on the meter--per manufacturer:
These units have a maximum continuous rating of 320 Amperes which must not be exceeded.
[ March 22, 2005, 04:03 PM: Message edited by: tshea ]
It's great for resi services where a 40 space panel (200A) is not quite big enough. You can put 2 panels next to each other and run both service entrance conductors to the load lugs of the meter pedestal. The lugs are rated for 2 conductors!
I commercial work same situation applies. "Generally" a 200 Amp panel isn't loaded up to 200A, for obvious reasons. If you can load it to 160 and have the other panel loaded at 160 the 320 meter socket pedestal works great.
You can size your conductors at 3/0 for each 200Amp panel. You could even install 2-100Amp panels and install #3 to each.
If I was going to use a single main, I would probably use a 400A switch and use the fuses for the calculated load. edit Not to exceed 320
edit:
Just checked specs on the meter--per manufacturer:
These units have a maximum continuous rating of 320 Amperes which must not be exceeded.
[ March 22, 2005, 04:03 PM: Message edited by: tshea ]
charlie
Senior Member
- Location
- Indianapolis
Re: 320 Amp Single Position Meter Socket
It matters not whether you use the 320 ampere meter fitting for residential, commercial, or industrial purposes. You may always use a 400 ampere service as a single overcurrent device or any combination with it as long as the load does not exceed 400 amperes as calculated in Article 220.
The meter fitting is rated backwards, think about it. You load the service at 100% of the non-continuous load plus 80% of the continuous load. You are loading the service the same as the rating of the meter fitting. Actually, the only way it doesn't work is if you have overcurrent devices that are rated for continuous loads at 100%.
It matters not whether you use the 320 ampere meter fitting for residential, commercial, or industrial purposes. You may always use a 400 ampere service as a single overcurrent device or any combination with it as long as the load does not exceed 400 amperes as calculated in Article 220.
The meter fitting is rated backwards, think about it. You load the service at 100% of the non-continuous load plus 80% of the continuous load. You are loading the service the same as the rating of the meter fitting. Actually, the only way it doesn't work is if you have overcurrent devices that are rated for continuous loads at 100%.
james wuebker
Senior Member
- Location
- Iowa
Re: 320 Amp Single Position Meter Socket
Johnuia
These are great to use when you need a 400 amp meter. Don't have to use CT's. I just put one in and on the other side of the meter I put in a 200 amp Sq. D QO 40 space panel and a 200 disconnect for a house that hasn't been built yet. I ran 3/0 to each panel. Doing it like this is OK as long as they are grouped together. Meaning the panels or disconnects are next to each other. Charlie was correct in his answer also about the load.
Bye now,
Jim
Johnuia
These are great to use when you need a 400 amp meter. Don't have to use CT's. I just put one in and on the other side of the meter I put in a 200 amp Sq. D QO 40 space panel and a 200 disconnect for a house that hasn't been built yet. I ran 3/0 to each panel. Doing it like this is OK as long as they are grouped together. Meaning the panels or disconnects are next to each other. Charlie was correct in his answer also about the load.
Bye now,
Jim
Re: 320 Amp Single Position Meter Socket
But 100% continuous rated overcurrent devices cost twice as much as 80% rated and are really available in a frame size of 800 amps and up. That is, a 400 amp 100% rated circuit breaker costs twice as much as an 800 amp 80% rated circuit breaker. No matter how you slice it, 100% cost more than a larger service that is 80% rated unless you are talking about 2000 amp and larger switchboards where you do need a precise trip point.
But 100% continuous rated overcurrent devices cost twice as much as 80% rated and are really available in a frame size of 800 amps and up. That is, a 400 amp 100% rated circuit breaker costs twice as much as an 800 amp 80% rated circuit breaker. No matter how you slice it, 100% cost more than a larger service that is 80% rated unless you are talking about 2000 amp and larger switchboards where you do need a precise trip point.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: 320 Amp Single Position Meter Socket
See 230.40 exception 3
I do this for garages. as we have to have a disconnect anyway at the garage why install one at the house and if the conductors don't enter any other buildings other than what is allowed by 230.70(A)(1) then the only OCPD needed is at the service disconnect for this other building.
[ March 23, 2005, 01:50 AM: Message edited by: hurk27 ]
Jim there is no requirement for grouping of the disconnects or even a disconnect at this building for another building for that matter. 230.71 only require that each building must have a disconnect and it is allowed to have up to 6 that must be grouped at each building. If you were to hit the lugs of the 320 meter and run strait to the other building the NEC would just treat this run as set of service entrance conductors and the disconnect for that building would be the "service disconnect" for that building.
See 230.40 exception 3
I do this for garages. as we have to have a disconnect anyway at the garage why install one at the house and if the conductors don't enter any other buildings other than what is allowed by 230.70(A)(1) then the only OCPD needed is at the service disconnect for this other building.
[ March 23, 2005, 01:50 AM: Message edited by: hurk27 ]
james wuebker
Senior Member
- Location
- Iowa
Re: 320 Amp Single Position Meter Socket
hurk27
The way I read it, you are correct. But were I'm at the electric company wouldn't allow doing it like that. If there's a fire or something else that the electric has to be shut down they what the main near the meter so they know were to shut off the power. Your way would be OK if there was a main disconnect for both building or services.
Thanks!
Jim
hurk27
The way I read it, you are correct. But were I'm at the electric company wouldn't allow doing it like that. If there's a fire or something else that the electric has to be shut down they what the main near the meter so they know were to shut off the power. Your way would be OK if there was a main disconnect for both building or services.
Thanks!
Jim
charlie
Senior Member
- Location
- Indianapolis
Re: 320 Amp Single Position Meter Socket
Jim, how does the serving electric utility have any authority past the service point other that the meter and meter fitting? I think they could be challenged through the public service commission.
Jim, how does the serving electric utility have any authority past the service point other that the meter and meter fitting? I think they could be challenged through the public service commission.
james wuebker
Senior Member
- Location
- Iowa
Re: 320 Amp Single Position Meter Socket
Charie
Electric company here has the right not to hook you up until everything is their way and alot of time the local inspector sees it that way. They try to stay close to the NEC. They have to make sure grounding is correct inside and outside before they will heat the wires up. Now if you get the right person checking things out they might drift our way a little. Now if I go to a different county with a different electrical supplier they will have their owe set of rules. I wish we all could go by one book. It would at least make it easier around here.
Thanks Charlie!
Jim
Charie
Electric company here has the right not to hook you up until everything is their way and alot of time the local inspector sees it that way. They try to stay close to the NEC. They have to make sure grounding is correct inside and outside before they will heat the wires up. Now if you get the right person checking things out they might drift our way a little. Now if I go to a different county with a different electrical supplier they will have their owe set of rules. I wish we all could go by one book. It would at least make it easier around here.
Thanks Charlie!
Jim
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