Ground Question/Panel Question

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Old 03-09-03, 03:51 PM
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BuzzHazzard
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Question Ground Question/Panel Question

A few quick questions re: new construction:

1) How does one install the two required grounding rods for a panel rough-in when the area outside near the meter has not been graded to anywhere near final grade (probably 1-2' of fill left). That's probably an easy answer for most of you but I'm not sure how to do it. Leave the rods out to what I believe will be final grade? And in that case, for the time being at least, the ground wire that continues to the second rod would be suspended and open to possible damage during the backfill.

2) In addition to a 2-1/2" knockout for the SE cable, on the top where my cables will enter (basement installation), my panel has 10-12 1/2" knockouts, two 3/4" knockouts, and two 1-1/4" knockouts. In another install I've looked at, the electrician popped out the two 1-1/4" knockouts and placed lots of NM cables (mixture of AWG sizes) in each 1-1/4" clamp. Is this standard procedure and if so, how many cables is too many?

3) I am installing a Leviton whole-house surge surpressor. It is in a 6"x6" box which connects to the service panel with a short length of 3/4" conduit. Since I have TWO panels in parallel, is one surge supressor on one panel enough, or is it necessary (or preferable) to install one supressor on each panel? (I'm suspecting the latter as an incoming surge would not necessarily be supressed in the second panel.)

Thanks in advance!

Rob
 
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Old 03-09-03, 04:31 PM
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Regarding the surge suppressor (aka TVSS), if the two panelboards are installed with a short whip between, then one TVSS is plenty. TVSS is conencted in parallel and offers protection to both.
If they are far apart, then place the TVSS in the panel closest to the utility meter, so as to squelch the surges from the utility. There is some claims that indicate that surges are produced from within the home. In my opinion, the ones to watch out for are from the utility.
 
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Old 03-09-03, 07:28 PM
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lestrician
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On the ground rods, you can install them hoping that the finish grade is what you expect, but better yet, install them now, weld the grounding wire to them with a "one shot" and be done with it, without question of where they'll end up.
As for putting numerous NM cables in one hole, don't do it unless you have a connector rated for such, it won't pass inspection. Just because someone else did it, doesn't make it right.
 
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Old 03-09-03, 07:54 PM
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BuzzHazzard
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Originally posted by lestrician
As for putting numerous NM cables in one hole, don't do it unless you have a connector rated for such, it won't pass inspection. Just because someone else did it, doesn't make it right.
That was always my impression. How do you tell what a connector is rated for?--nothing stamped on the connector or packaging.

The panel I referred to passed inspection fine--even had only ground rod. Sometimes it seems like the NEC depends on which side of the bed the inspector woke up on.

Guess I'll plan on punching out all the 1/2' knockouts as I need them. The two 1-1/4" holes seemed like a quicker (and I had hoped legal) way to go.

Thanks.
 
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