RESIDENTIAL TRIPLEX DWELLING SERVICE

[Keldra]

Hello to the forum i am newbie. My business partner (Master) is away for now and iam trying to bid a service replacement due to storm (Texas). My issue is i have to replace a service on a residental triplex we have a 3 gang meter box with a overhead riser fed with 3wire 250 mcm and below the meter bases we have 3 seperate 100 amp panels with mains feeding the units . What i am trying to determine is do we need to install just new meter bases or do we have to use the type of meters that have the main built into it. Also what size wire for the cold water ground And what size conducter for the ground rod. thx very much

 

[MasterTheNEC]

Keldra,

While this is not a DIY forum I guess the mods have determined your request is "LIGIT", otherwise it would have been removed by now for sure.

As you stated you currently have (3) meter bases with service disconnects located underneath them (Code Compliant), if you wanted to replace the meter bases with meter bases and service disconnection means combo's then that would be code compliant also. If the choice came down to money and the service disconnects are ok and it is just the meters that need replacing then I would simply leave the service disconnects and fix the meters.

The choice is going to be yours and it will be done based on cost...ganged meter units with built in SUSE rated disconnects are probably more expensive than meter sockets feeding grouped single 100A service disconnects to re-supply the remote panels in the dwellings but again that's a design choice.

As for the grounding.....since you have multiple disconnection means look at NEC 250.64 closely....

rather than get into a DIY thing here...I will direct you to crack open the 2014 NEC (you are in Texas right) and look at 250.50, 250.66, 250.64 and 250.66(A) and then bring your specific questions back individually.

Just my opinion on it.

 

[kwired]

Hello to the forum i am newbie. My business partner (Master) is away for now and iam trying to bid a service replacement due to storm (Texas). My issue is i have to replace a service on a residental triplex we have a 3 gang meter box with a overhead riser fed with 3wire 250 mcm and below the meter bases we have 3 seperate 100 amp panels with mains feeding the units . What i am trying to determine is do we need to install just new meter bases or do we have to use the type of meters that have the main built into it. Also what size wire for the cold water ground And what size conducter for the ground rod. thx very much

If you have 100 amp mains directly below the meters (which I think you are describing it that way) then outside of some local code you would only need to replace with a meter with no disconnect similar to what you had before.

Grounding electrode conductor need sized to the 250 MCM service conductor - but there is more then one way to install it/ place(s) to land it.

A conductor to a ground rod never needs to be larger then 6 AWG if it is the only connection to that rod.

 

[MasterTheNEC]

If you have 100 amp mains directly below the meters (which I think you are describing it that way) then outside of some local code you would only need to replace with a meter with no disconnect similar to what you had before.

Grounding electrode conductor need sized to the 250 MCM service conductor - but there is more then one way to install it/ place(s) to land it.

A conductor to a ground rod never needs to be larger then 6 AWG if it is the only connection to that rod.

And just to add....even if you are adding a bonding jumper to a second rod....that bonding jumper need only be 6 AWG CU as well.

This may Help...
250.64(D) Building or Structure with Multiple Disconnecting
Means in Separate Enclosures.

For a service or feeder with
two or more disconnecting means in separate enclosures supplying
a building or structure, the grounding electrode connections
shall be made in accordance with 250.64(D)(1), (D)(2),
or (D)(3).

then .....

250.66(A) Connections to a Rod, Pipe, or Plate Electrode(s).


Where the grounding electrode conductor is connected to
a single or multiple rod, pipe, or plate electrode(s), or any
combination thereof, as permitted in 250.52(A)(5) or (A)(7),
that portion of the conductor that is the sole connection to the
grounding electrode(s) shall not be required to be larger than
6 AWG copper wire or 4 AWG aluminum wire.

Code Content courtesy of the National Fire Protection Association - Get Your NFPA 70 Today !

 

[kwired]

And just to add....even if you are adding a bonding jumper to a second rod....that bonding jumper need only be 6 AWG CU as well.

This may Help...
250.64(D) Building or Structure with Multiple Disconnecting
Means in Separate Enclosures.

For a service or feeder with
two or more disconnecting means in separate enclosures supplying
a building or structure, the grounding electrode connections
shall be made in accordance with 250.64(D)(1), (D)(2),
or (D)(3).

then .....

250.66(A) Connections to a Rod, Pipe, or Plate Electrode(s).


Where the grounding electrode conductor is connected to
a single or multiple rod, pipe, or plate electrode(s), or any
combination thereof, as permitted in 250.52(A)(5) or (A)(7),
that portion of the conductor that is the sole connection to the
grounding electrode(s) shall not be required to be larger than
6 AWG copper wire or 4 AWG aluminum wire.

Code Content courtesy of the National Fire Protection Association - Get Your NFPA 70 Today !

Correct, but in any rare instance where you were to go from service to a rod and then to a water pipe or to structural steel it needs full sized to T250.66.

 

[GoldDigger]

Quibble:
If you take a single conductor and run it through a clamp on the rod and on to a water pipe or CEE, then it is still "the only conductor going to the rod" even though it is not "a conductor going only to the rod."

 

[MasterTheNEC]

Correct, but in any rare instance where you were to go from service to a rod and then to a water pipe or to structural steel it needs full sized to T250.66.

Indeed...just trying to give some references since clearly they do not have a code book. Clearly the use of 250.66(A) refers to the sole connection and as you described it would not be such a connection. Sadly we can't give the OP all of the potential situations and examples...they need to get a code book and read it.

 

[MasterTheNEC]

Quibble:
If you take a single conductor and run it through a clamp on the rod and on to a water pipe or CEE, then it is still "the only conductor going to the rod" even though it is not "a conductor going only to the rod."

Ok....NOW we can really start to get into some debates on this. If you connect that "conductor" to the rod then it is terminated to it.....at that point all of what kwired stated would still be correct.

 

[Little Bill]

Quibble:
If you take a single conductor and run it through a clamp on the rod and on to a water pipe or CEE, then it is still "the only conductor going to the rod" even though it is not "a conductor going only to the rod."

Ok....NOW we can really start to get into some debates on this. If you connect that "conductor" to the rod then it is terminated to it.....at that point all of what kwired stated would still be correct.

Since the title of the part of the article is:

Connections to Rod, Pipe, or Plate Electrodes.

A water pipe can be considered an electrode if it meets the requirements.

Then the article says this:

Where the grounding electrode conductor is connected to
a single or multiple rod, pipe, or plate electrode(s), or any
combination thereof, as permitted in 250.52(A)(5) or (A)(7),
that portion of the conductor that is the sole connection to the
grounding electrode(s) shall not be required to be larger than
6 AWG copper wire or 4 AWG aluminum wire.

Notice the "s" at the end of electrode. That looks like a rod then a pipe would make it "electrode(s)" and the #6 would be good if you just ran the GEC through the clamp at each. That would be the only connection to each electrode.

That's how it appears to read anyway!

 

[Keldra]

THANK YOU FOR YALL'S RESPONSES KELDRA