Service Upgrade


  #1  
Old 06-17-04, 01:12 PM
MJB32
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Service Upgrade

I recently purchased an older home that has only 60amp service. I would like to upgrade to 100amp.
My question concerns grounding of the new panel.
Current design has two hot wires and one ground coming into panel. The Ground is then jumpered to water pipes with a fairly large conductor( probably #2).This connection is made at the nearest point to panel, but on the house side of water meter. There is a jumper around meter which is located on other side of basement approx. 30' away.
Is this grounding ok, or do I need to bury a grounding rod and ground new panel to that?
If I do need a grounding rod should I also leave grounding to water pipes as is?
thank you
 
  #2  
Old 06-17-04, 01:39 PM
R
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The three wires coming into the panel are two hot wires and the return, or neutral. There is no ground coming in.

The neutral is bonded to your water pipes via the wire that goes to the water pipe. This connection may or may not supply a ground, depending on the pipes. No matter what, the water pipes in the house must be bonded to the neutral, if they are metal.

If you replace the panel you are generally required to bring it up to code. This means proper grounding. Proper grounding now consists of two approved methods.

If the water pipe is metal and extends into the ground outside your house for at least ten feet then this connection counts as one of the required approved grounding connections. If the pipe is plastic or does not extend far enough into the ground then it does not count.

The current connection to the water pipes that you have does not sound correct for this connection be a ground connection. This connection should be made close to the point where the pipes enter the house. 30 feet away is not close. I believe that this connection needs to be made within five feet, but I may be wrong.

The other ground connection is usually easiest satisfied by a ground rod, which is a copper rod inserted into the ground. It needs to be a certain size and connected with a certain size wire.
 
  #3  
Old 06-17-04, 02:22 PM
rlrct
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What Bob said, plus a couple of clarifiers:
  • The attachment point to the metal water pipe is within 5' of entering your house. If there are jumpers around the water meter, that is correctly wired.

  • In my town, when we upgraded our service from 100 to 200 amps, we had to drive (2) copper ground rods and tie those in as part of the "Grounding Electrode System" which is what's tied into your service equipment (where your service disconnect is). We also have metal water pipe and have a #4 conductor running to that as well.

  • You should check to make sure that the service laterals are capable of handling the upgrade (the LOPOCO wires from the pole/transformer to your house) by calling the LOPOCO. You may need to replace the meter socket.

  • If your panel is where the main disconnect is, then having everything bonded there is fine. If you have a separate service disconnect (between the panel and power meter) that is more than 10' away, the feed from the disconnect to the panel should be a 4-wire feed. At that point you might be into a panel swap because it could be easier to do that than to retrofit and separate the neutrals and grounding conductors in your old panel.


  • Rob
 
  #4  
Old 06-17-04, 03:27 PM
Rlfrazee
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You might give some consideration to upgrading to 150 or even 200 amps, todays electrical demands may quickly use up your 100 amp service. Before contacting your power company about upgrading I would or have someone do a demand load calculation taking into consideration what you plan to add to the electrical system now and in the future. You may discover that 100 amps will not be appropriate to meet those needs and will give you a knowledgable figure to present to the power company for your upgrade. GL.......RL
 
  #5  
Old 06-18-04, 06:02 AM
MJB32
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Thank you all.
Your suggestions have been very helpful.
With two teenage daughters (hair dryers, tvs... ) 150amp may make more sense.
 
 

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