Sizing Service Entrance Cable

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  #1  
Old 01-25-06, 08:41 PM
Frank_N
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Sizing Service Entrance Cable

Should I use 2-2-2 aluminum SE cable or 2-2-4 for a 100 amp service?

Frank
 
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Old 01-25-06, 08:55 PM
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SE cable usage

First:[*]What is the relationship of the SE cable to your meter base,[*]Is there any overcurrent device before the SE cable,[*]Does this SE cable run thru any portion of your structure.

Originally Posted by Frank_N
Should I use 2-2-2 aluminum SE cable or 2-2-4 for a 100 amp service?

Frank
 
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Old 01-25-06, 09:00 PM
Frank_N
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The SE runs from the bottom of the meter pan through the house about 5-6' to the panel.

Frank
 
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Old 01-25-06, 09:44 PM
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The NEC allows the neutral size to be reduced based on the maximum unbalance of the load between the neutral and either hot wire. By code this could be as small as a #8 on a 100 AMP service. But, unless you can calculate the unbalanced load go with the 2-2-2. Frequently a #4 is OK but sometimes a 3 will be required and this is no place to be guessing. Cost isn't an issue here.

UNK
 
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Old 01-25-06, 09:57 PM
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Use 2-2-2.

Someday someone will have a computer and other electronic equipment in the house.

The larger diameter wire hauls the high frequency noise away much better.
 
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Old 01-26-06, 03:17 AM
Frank_N
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Thank you

Ill install the 2-2-2
 
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Old 01-26-06, 04:07 AM
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I use 2-2-4 or 4/0-4/0-2/0, for 100 and 200 amps. It's all my supply house carries.
I've never had one complaint about computer "noise".
I myself have 4 computers and a LOT of electronic equipment, it's not a problem.
 
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Old 01-26-06, 08:00 AM
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Originally Posted by Speedy Petey
I've never had one complaint about computer "noise".
That doesn't mean that you aren't pushing the limit. The point is that computers/electronics are increasing.

The physics behind high frequency conduction speaks for itself.
The larger the neutral the better noise is conducted back to the transformer.
As computers move toward making ever higher frequency noise, the larger neutral is even better.

50 years ago, who knew?

You can't go wrong with the larger neutral for many reasons.
 
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Old 01-26-06, 08:27 AM
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The physics behind high frequency conduction speaks for itself.
The larger the neutral the better noise is conducted back to the transformer.
As computers move toward making ever higher frequency noise, the larger neutral is even better.


Since when is the neutral the means of dumping high frequency noise? The ground and proper sheilding is the means for dumping most HF noise. In fact many commercial computer installations use 240 volt on-line UPSs to power computers precisely because it does away with neutral CAUSED noise problems.

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Old 01-26-06, 09:11 AM
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Since when is the neutral the means of dumping high frequency noise?
It is inevitable feedback from inexpensive switching power supplies for one thing.




The ground and proper shielding is the means for dumping most HF noise.
No, not at all. I am talking about inductive noise (power supplies, motors) that has nothing to do with an equipment ground or shielding.




In fact many commercial computer installations
I believe we're taking about residential.

You can't go wrong with the larger neutral. Computer power supplies put noise on the grounded and ungrounded conductors.
The larger the diameter of these conductors, the better.

(The same holds for the grounding conductors too, and fortunately these are the same size as the other conductors in internal wiring. But this doesn't mitigate the noise from switching power supplies.)
 
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Old 01-26-06, 12:21 PM
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Originally Posted by bolide
That doesn't mean that you aren't pushing the limit.
So tell me what the tangible or direct issue is then. What exactly is at the limit?
How is this "feedback" shown, seen or noticed.
Like I said, I see, and have never seen, any problems in ANY installation.
 
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