My first 320 residential install

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hotblueelectric

hotblueelectric

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Dallas Texas
1. Im installing a 320 amp meter base feeding 2 exterior 200 amp circuit breaker disconnects, feeding 2 200 amp interior panels.
2. I’m running a #6 bare from CB #1 to ground rod #1, then on to ground rod #2, then to CB #2.
3. Both CB’s disconnects bonded.
4. Im running a #6 stranded from each (non bonded, ground and neutral separate) sub panel to each CB.
5. I’m running an un broken #6 stranded from each CB to the rebar. ( does this #6 need to be un broken? Code reference?)
Does this look correct? Am I missing something? Your advise is greatly appreciated.
 
Does you POCO allow you to connect in the meter base ?
If so, I would runa #4 to my UFER and split bolt off with #6s to my ground rod(If ground rad was required)
 
I agree with Little Bill-if you have a CEC you don't need the ground rods at all. Otherwise the OP's plan is valid except as noted the CEC will need to be #4. Also as noted, if the POCO allows the GEC at the meter you could just connect a single GEC at the meter and be done with it.
 
hotblueelectric said:
2. I’m running a #6 bare from CB #1 to ground rod #1, then on to ground rod #2, then to CB #2.
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This isn't actually required as another poster mentioned because you have a CEE. However if you did have to use ground rods why couldn't you just run number six between the two circuit breakers and then to the two ground rods?
 
hotblueelectric said:
1. Im installing a 320 amp meter base feeding 2 exterior 200 amp circuit breaker disconnects, feeding 2 200 amp interior panels.
2. I’m running a #6 bare from CB #1 to ground rod #1, then on to ground rod #2, then to CB #2.
Click to expand...
Even though this is allowed and even shown in Soares, IMO it shouldn't be, it makes a neutral loop between the two disconnects. 1661687598717.png
hotblueelectric said:
petersonra said:
This isn't actually required as another poster mentioned because you have a CEE. However if you did have to use ground rods why couldn't you just run number six between the two circuit breakers and then to the two ground rods?
Click to expand...
Click to expand...
That is the way it should be done
 
hotblueelectric said:
1. Im installing a 320 amp meter base feeding 2 exterior 200 amp circuit breaker disconnects, feeding 2 200 amp interior panels.
2. I’m running a #6 bare from CB #1 to ground rod #1, then on to ground rod #2, then to CB #2.
3. Both CB’s disconnects bonded.
4. Im running a #6 stranded from each (non bonded, ground and neutral separate) sub panel to each CB.
5. I’m running an un broken #6 stranded from each CB to the rebar. ( does this #6 need to be un broken? Code reference?)
Does this look correct? Am I missing something? Your advise is greatly appreciated.
Click to expand...

Many people struggle with grounding for multiple service disconnects. I don't believe anyone as thrown out any code references, See 250.64(D)
 
roger said:
It makes a neutral loop between the two disconnects.
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There will always be a neutral loop unless a single GEC is landed upstream of the neutral division point. But I guess your point is that the method of one common GEC plus taps minimizes the size of the neutral loop.

Cheers, Wayne
 
roger said:
Even though this is allowed and even shown in Soares, IMO it shouldn't be, it makes a neutral loop between the two disconnects. View attachment 2561941

That is the way it should be done
Click to expand...
Since the disconnects are required to be grouped there wouldn't be much current flowing on the gec. In addition all gec can have current on them that is just part of their purpose more impedence reduces it but at the disconnects there will be a very balanced load so the starting potential current is low then there is a large neutral going a shorter distance to the meter than the longer smaller gec so what current goes on that will be reduced. This is much less an issue than if it was a situation like using metallic raceway between meter and disconnect which is allowed anyway.
 
letgomywago said:
Since the disconnects are required to be grouped there wouldn't be much current flowing on the gec.
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Look at the drawing, you could have as much as 200 amps on the #6. Imagine the neutral on the right disconnect is broken, now all the neutral current from that disconnect is on the #6 to the left hand disconnect. I would much rather have 200 amps flowing in a metallic nipple than a # 6
 
wwhitney said:
There will always be a neutral loop unless a single GEC is landed upstream of the neutral division point. But I guess your point is that the method of one common GEC plus taps minimizes the size of the neutral loop.

Cheers, Wayne
Click to expand...
Nope, that is not my point. Taps can create the same problem. In the illustration below it would be possible for all the neutral current from the right disconnect to be carried on the #8 tap if the right hand neutral were broken / lost

1661707633908.png

My agreement with Bob is how it should be done.
 
GEC taps and loops were the biggest problem with community metallic water systems
 
We can't "what-if" about open neutrals any more than other contingencies. Well, we can, but it gets expensive quickly.
 
LarryFine said:
We can't "what-if" about open neutrals any more than other contingencies. Well, we can, but it gets expensive quickly.
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So how do you see Bob's method being more expensive? I see it being cheaper in most cases, less material less cost, what do you think?
 
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