EGC size with multiple service drops

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Dansos

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We are replacing a 100A Main breaker load center in a resi property. This particular service drop is a single 100A meter and drop. Next to this meter is a 200A service drop powering (2) 100A panels. All 3 panels are in same room in basement. Currently only a single ground rod with #6 Cu running to it and that is the ONLY ground present, no panels bonded either.

Do we need to include the 200A service into our calc for determining water pipe ground size?

Do we need to bond the other panels to the one we are replacing?
 
Dansos said:
We are replacing a 100A Main breaker load center in a resi property. This particular service drop is a single 100A meter and drop. Next to this meter is a 200A service drop powering (2) 100A panels. All 3 panels are in same room in basement. Currently only a single ground rod with #6 Cu running to it and that is the ONLY ground present, no panels bonded either.

Do we need to include the 200A service into our calc for determining water pipe ground size?

Do we need to bond the other panels to the one we are replacing?
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Yes size the water pipe bond based on the size of all service entrance conductors.
per 250.66, I am guessing you'll end up with 2 CU
The #6 to the ground rod is fine.
Usually you need two new ground rods on a service change or a test on the existing.
Happy holidays.
Edit and yes bond all the panels, the GEC's in one location such as the new panel.
 
All the service disconnecting means need connected to the grounding electrode system, but connection can be any point ahead of the service disconnect(s) up to the point of connection to service drop or lateral as well. (some jurisdictions won't allow inside a meter because access restrictions by POCO lock or seal on the meter)

If the ground rod(s) is the only electrode then a 6 AWG is largest conductor ever needed regardless of what the service consists of.
 
Felon it sure seemed like two different drops to me.
kwired said:
All the service disconnecting means need connected to the grounding electrode system, but connection can be any point ahead of the service disconnect(s) up to the point of connection to service drop or lateral as well. (some jurisdictions won't allow inside a meter because access restrictions by POCO lock or seal on the meter)

If the ground rod(s) is the only electrode then a 6 AWG is largest conductor ever needed regardless of what the service consists of.
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The OP was asking about water pipe ground (Bond) size. Per 250.104 even if its not an electrode they need to bond it.
 
electrofelon said:
If there are two service drops, sounds like a violation to me, although I suppose one could claim they had no control over how the utility feeds each riser.
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We have places in our area with 2 drops.
Some residential, some commercial.

It's rarely engineered, it's the linemen who do it
 
Yeah they are pretty common around here to older apartment houses and retail.
Never thought about the NEC violation, I wonder if its a NESC violation?
The thing I run into with this exact setup is you always get measurable current on the bonds between panels due to the different size neutrals up the 100A and 200A service risers.
As the neutrals are parallel conductors.
 
electrofelon said:
If there are two service drops, sounds like a violation to me, although I suppose one could claim they had no control over how the utility feeds each riser.
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We do have "paralleled" drops sometimes. But I call that one drop with parallel conductors and/or multiplexed cable assemblies
 
kwired said:
We do have "paralleled" drops sometimes. But I call that one drop with parallel conductors and/or multiplexed cable assemblies
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It's only paralleled if all the drop conductors per leg are connected to all the riser conductors per leg.

But if there's an existing 200 amp service providing power for 3 meters and someone adds a 200-amp service next to it for a fourth, that's not parallel
 
James L said:
It's only paralleled if all the drop conductors per leg are connected to all the riser conductors per leg.

But if there's an existing 200 amp service providing power for 3 meters and someone adds a 200-amp service next to it for a fourth, that's not parallel
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Understand and yes what I am talking about is actually parallel. I wouldn't say it has to connect to all riser conductors, just connect to each other at each end of the parallel section. Maybe you have a 4 wire delta secondary and a riser with three phase and a riser with single phase, but enough capacity the POCO parallels two sets of quad cable for the drop. No VD situations gains if you don't tie them together at both ends, and keep the parallel portions same length and size as well.
 
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