New Service Panel - Different Location

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Old 07-08-06, 11:03 AM
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New Service Panel - Different Location

I'm installing a new main service panel. I plan to leave existing one and use as a J-B. For a variety of reasons the new box will be about two feet away on a wall perpendicular to the existing service panel.

Can I run THWN for the service leads in the wall (sheetrocked both sides) with out using conduit? If not rather then a single conduit for the two hots and neutral which would be difficult to run for a variety of reasons can I protect each individually with 1/2" or 3/4" greenfield. If I use greenfield will 1/2" be large enough for a single #2 THWN conductor?

I was planing on using the # 2 because I have it already but what is the smallest that could be used for a two foot run to a 100 amp service panel?
 
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Old 07-08-06, 11:12 AM
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[QUOTE]
Originally Posted by ray2047
Can I run THWN for the service leads in the wall (sheetrocked both sides) with out using conduit? If not rather then a single conduit for the two hots and neutral which would be difficult to run for a variety of reasons can I protect each individually with 1/2" or 3/4" greenfield. If I use greenfield will 1/2" be large enough for a single #2 THWN conductor?
NO, no and no.
I was planing on using the # 2 because I have it already but what is the smallest that could be used for a two foot run to a 100 amp service panel?[/
QUOTE]#3

be aware that you cannot use the old panel box as a junction box for the feeders and the circuits in the house. They need to be seperated.
 
  #3  
Old 07-08-06, 12:57 PM
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The feeders must run directly to the new panel. The wires from the new panel to the old one must be either individual cables (NM-B) or you must use individual conductors in conduit. Each conduit needs it;s own ground, but you can put more than one circuit in a conduit.
 
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Old 07-08-06, 01:14 PM
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The feeders must run directly to the new panel.
So am I understanding correctly I can not extend the new feeders from the existing feeders using the old service panel as a J-B even if I install a seperate J-B for extending the individual circuits?
 
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Old 07-08-06, 07:39 PM
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The wires from the utility supply to the first overcurrent protective device (OCPD) are called the service conductors. Wires that originate at an OCPD and supply power to additional OCPDs are called feeder conductors.

I'm too lazy to look it up but I am pretty sure that service conductors may NOT be spliced anywhere between the metering device and the first OCPD. This would preclude your being able to splice from your existing service conductors to extend into your new panel.

Also note that if you use conduit between the new and old panels for routing conductors back to the old panel for the existing circuits AND this conduit is more than 24 inches long then you MUST apply conductor de-rating to all conductors in any conduit that contains more than three current-carrying conductors.
 
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Old 07-09-06, 12:23 AM
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Originally Posted by furd
I'm too lazy to look it up but I am pretty sure that service conductors may NOT be spliced anywhere between the metering device and the first OCPD. This would preclude your being able to splice from your existing service conductors to extend into your new panel..
Thank you for the reply. I do not have room to install a box large enough for my needs where the current box is. Could I install a one or two breaker box as the first OCPD and run form that?
 
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Old 07-09-06, 12:42 AM
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Absolutely. Assuming that you do not desire to increase the service rating, that is, you do not desire any greater amount of electrical capacity for usage, you would select a panel with the appropriate rating and install a main circuit breaker of that rating to feed the new panel that you wish to place in the adjacent location.

This arrangement would make the single main breaker panel the termination of the service and from the load side of that breaker you would have feeder conductors to the new panel mounted adjacent. The "second" panel (the new one being fed from the new main breaker panel) would now be classified as a sub-panel and all of the rules concerning neutrals, grounding and bonding of a sub-panel would apply. From this panel you could run (relatively) short cables to junction boxes where you tie into the existing wiring.

One caveat: Your LOCAL "Authority Having Jurisdiction" (AHJ), or in other words, the electrical inspection department in your area, MAY have some serious reservations about you re-working an existing service without bringing it up to current codes. I strongly urge you to talk to these people and obtain the proper permit BEFORE starting this project, even before purchasing any equipment.
 
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Old 07-09-06, 01:17 AM
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Thank you for your replies and advice. My current attempts are to bring a 40+ year old system that has deteriorated to code within my budget. Your replies have been a great help in updating my knowledge first learned in the early fifties from books probably written in the forties.
 
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Old 07-09-06, 05:22 AM
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If you want the most appropriate solution, then replace your existing panel. This is clearly cheaper tan trying to buy and run cable between the old panel and the new one.
 
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Old 07-09-06, 08:30 AM
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Originally Posted by racraft
If you want the most appropriate solution, then replace your existing panel. This is clearly cheaper tan trying to buy and run cable between the old panel and the new one.
That would be the best idea but the current box is installed at a point where another addition was added to the house. The space is physically restricted by the way the addition was framed and not wide enough for a newer service panel.
 

Last edited by ray2047; 07-09-06 at 01:04 PM.
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Old 07-09-06, 10:38 PM
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Ok I think I have my plan finalized but I have a grounding question. Assuming a 70 amp service would the ground have to be #6 or larger. Would #4 be adequate for the current carrying wires on a run of less then four feet? Run will be in 1-1/4" EMT.
 
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Old 07-10-06, 10:07 AM
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If all you currently have is a 70 Ampere service (unlikely) then you really do need to upgrade the entire service. I rather doubt that your local AHJ will issue a permit for your proposed job.

There are some things that you really should not try to cut corners on or do cheaply, this is one of them.
 
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