320 service Main Bonding Jumper

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RichEng

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On a residential 320 service the POCO provides the meter can with (2) 200 amp disconnects.
I wanted to do (2) 200 amp panels inside the house each fed from the disconnects at the meter can.

(It's a relatively large house with a 20KW backup heater on the geothermal heat pump and PTAC units in the Bonus room above the attached garage.)

Upon reading 250.28 (D) (2) I am lead to believe that each 3 wire panel should have its own Main Bonding Jumper and any sub panels off of these main panels would have the neutral and grounds separated.

Is this correct?
 
The bonding jumper needs to be at the service disconnects, Then it is 4 wire from there on out, unless it is a seperate building and you are still under 05.
 
RichEng said:
On a residential 320 service the POCO provides the meter can with (2) 200 amp disconnects.
I wanted to do (2) 200 amp panels inside the house each fed from the disconnects at the meter can.

(It's a relatively large house with a 20KW backup heater on the geothermal heat pump and PTAC units in the Bonus room above the attached garage.)

Upon reading 250.28 (D) (2) I am lead to believe that each 3 wire panel should have its own Main Bonding Jumper and any sub panels off of these main panels would have the neutral and grounds separated.

Is this correct?
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You are correct. :) I agree....Nope. don't agree. read below.

I've re-read your post and as ceb says, your service disconnects are at the metering location. You'll need 4-wire to the remote panelboards and 4-wire to any subpanels downwind from those. Your GES should originate at the meter service disconnects.
 
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RichEng said:
On a residential 320 service the POCO provides the meter can with (2) 200 amp disconnects.
I wanted to do (2) 200 amp panels inside the house each fed from the disconnects at the meter can.

(It's a relatively large house with a 20KW backup heater on the geothermal heat pump and PTAC units in the Bonus room above the attached garage.)

Upon reading 250.28 (D) (2) I am lead to believe that each 3 wire panel should have its own Main Bonding Jumper and any sub panels off of these main panels would have the neutral and grounds separated.

Is this correct?
Click to expand...

First thing I would like to know is where you are for a poco to provide a meter can with the disconnects?
If there is a meter combo set with 2 200amp breakers any thing downstream would be 4 wire separating the grounded conductors from the egc.
 
wbalsam1 said:
You are correct. :) I agree
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I may be reading something into the OP that isn't there, but it read to me that the panels are some where away from the main discos. This makes these other then "Main Panels" and the bonding would need to be at the main disconnects not at the panels.
 
acrwc10 said:
I may be reading something into the OP that isn't there, but it read to me that the panels are some where away from the main discos. This makes these other then "Main Panels" and the bonding would need to be at the main disconnects not at the panels.
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You're absolutely right. I edited my response to reflect my more informed position. I read the post too quickly to begin with and missed that the meter actually had the disconnects built in. I'm used to the 320 amp low-profile meter enclosures without disconnects installed. :smile:
 
ceb,

the poco provides the meter can with disconnects here in the great "wide-opening" (Wyoming).

The two main panels will be inside the house on the other side of the wall from the meter can. SEC's will only be ~6' long.

I asked the poco about the MBJ being in the meter can disconnect enclosure and I got a response of stunned silence.

Usually, the two disconnects are feeding separate buildings (i.e. barn and house) and MBJ in the meter can disconnect enclosure has not been done.

How is the MBJ done in other jurisdictions with a 320 service?

Also, even if I had a 200 amp service, the poco has a disconnect on the load side of the meter. Does that mean the MBJ should be in the meter can in that situation as well?
 
Yours is the 1st area I have know of where the utility supplies any disconnecting means. Some provide meter cans, some nothing.
In any event your 1st disconnecting means is your service disconnect and the MBJ is installed there. After that point there is no connection between grounding and grounded.
 
RichEng said:
ceb,

the poco provides the meter can with disconnects here in the great "wide-opening" (Wyoming).

The two main panels will be inside the house on the other side of the wall from the meter can. SEC's will only be ~6' long.

I asked the poco about the MBJ being in the meter can disconnect enclosure and I got a response of stunned silence.

Usually, the two disconnects are feeding separate buildings (i.e. barn and house) and MBJ in the meter can disconnect enclosure has not been done.

How is the MBJ done in other jurisdictions with a 320 service?

Also, even if I had a 200 amp service, the poco has a disconnect on the load side of the meter. Does that mean the MBJ should be in the meter can in that situation as well?
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Just as Augie47 stated it must be bonded at the first disco. and after that it must be 4 wire and separated.
I my area this is the way it goes. The neutral and gec are together in meter base on the load side. 3 wire to first disconnecting means. Any other panels that are feed from the first disco. 4 wire and separate the neutral and egc in the sub panels. The distance of the feed is irrelevant it can be 6 ft or 60 ft.
What type of disconnects do the poco's provide. Is it a 400amp meter combo or meter base with two separate enclosures that you attach to the base?
 
augie47 said:
In any event your 1st disconnecting means is your service disconnect and the MBJ is installed there. After that point there is no connection between grounding and grounded.
Click to expand...

What is the probability of being able to install two grounded conductors, two grounding conductors, a gec to the rod, and a gec to the water if equiped inside the meterbase with ocp.It would seem that an exception should be made to run the 3-wire to the first ocpd at the panel and not at the poco meterbase if a ground bar kit or lugs are not available.
 
If it were just a "POCO meter base",I agree..... and I guess that's common practice around here, but OP seems to have what we refer to as a "combo" and all of those I have seen have adequate terminations for grounding electrode coductors and equip. grounds.
 
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