GE panel allows 24 circuits but has16 ground locations - why?

I am installing a new GE subpanel (main lug) in my basement. The panel, rated for 125 amps, is fed off of a 100 amp breaker.
I noticed the following. The panel has slots for 24 breakers, and the inside of the panel door says that 24 breakers are allowed. However, the ground and neutral busses have 16 wire locations each, where each location is a hole into which a ground or neutral wire is fed and then screwed in place.
Why is this so? I mean, why would a panel allow 24 breakers and have busses that are smaller than necessary? Does code allow for ground and neutral wire locations to be doubled up? What if I want to install 17 breakers in the panel?
My work will be inspected with it is complete, so it must be completely code-compliant.
Thanks,
mh
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Some panels are designed and listed so that neutrals and grounds can be connected to the same buss if so then it will say so on a label in the panel. I had a panel like that in one house I lived in, but as I remember it did not have a separate ground buss just 2 neutral/ground busses 1 on each side.
On other types of panels, it is not uncommon that you would have to purchase an extra ground buss and install it but I never heard of having to buy more neutral busses. I have also seen many a panel with 2 wires in one slot. Not sure if it is legal? Kevin
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If the panel is to be used as a sub panel, the ground and neutral busses must be isolated, in many cases by adding a new and separate ground bar. In any event, you can double up on the ground conductors, but not the neutrals

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The panel is a subpanel, so I removed the metal bar that joined the neutral and ground busses.
Should I install a secondary neutral bus and connect it to the existing neutral bus? This neutral bus will need to float, I presume, so that it does not allow current to bleed into ground.
mh
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It probably would have been slightly easier to have left the entire existing buss as a neutral and added a ground detail

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Based on what?
If multiwire circuits (A-B-N) are used they use use 1 neutral and ground for 2 poles. For separate circuits a neutral from an A circuit and a B circuit can be wirenuted to a single wire to the neutral bar.
bud--
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NEC 2002: 408.21 allows only one neutral per lug.
UL Std. 67 (Panelboard Standard) permits up to three 10 AWG equipment grounding conductors to terminate on a single terminal, if the terminal is marked for this purpose.

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>>> In >>> any event, you can double up on the ground conductors, but not the >>> neutrals
>> Based on what?

Interesting. NEC 2005 moved 408.21 to 408.41, same wording. In the past I added a note referencing 110.14D: "Termimals for more than one conductor ... shall be identified", which, in effect, covers both provisions. [It is annoying to get bit by UL provisions that are not in the NEC.] More than 1 ground wire per terminal can't be used unless indicated in the panel.
bud--
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If you run a bunch of circuits in a conduit, you only need one ground wire for all of them. Of course, that doesn't explain the lack of neutrals though.
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On 3 Jan 2006 10:18:25 -0800, snipped-for-privacy@gmail.com wrote:

That doesn't sound right to me...
I can see running a bunch of switch(ed) legs from the SAME circut and sharing the ground (and nuetral), but not different circuts.
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Goedjn wrote:

If a raceway needs a ground wire (like PVC) and carries multiple circuits (say 20A, 30A, 50A) the code requires 1 ground wire sized for the largest fuse/circuit breaker (in this case 50A).
(2005NEC 250.122C)
bud--
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Bud-- ( snipped-for-privacy@isp.com) said...

You can wirenut in the panel, but I avoid that unless the neutral is for two parts of a single branch circuit -- two home runs should be avoided, but sometimes it is necessary for retro work. Also, we have a doorbell transformer attached to our panel and it is placed on a lighting circuit, so the neutrals are wirenutted together.
Check the specs for the panel - most studs on the neutral bus are designed for multiple wires, depending on their sizes.
Our inspector didn't have a problem with multiple neutrals or grounds using a single terminal.
However, I will mention this, though it is a bit off topic: he did mention that trying to be too neat can be a problem! Running a bunch of neutrals nice and neatly together from where their cables enter the panel to the neutral bus can be an issue. Spread them out a bit so there is a bit of air between them. A heavy load on a couple of circuits with closely located neutrals in the panel can lead to a heat buildup!
--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
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NEC 408.41 prohibits more than one neutral under a terminal
said...

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On 2 Jan 2006 18:40:29 -0800, snipped-for-privacy@yahoo.com wrote:

You need the bus expansion kits.
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Read the UL listing cover information. Most residential manufacturers say that the bigger holes in the ground buss can contain more than one wire of the same size. At least my SQD Homeline did.
I know of no requirement that they must provide you with the maxium number of wires for the maxium number of breakers.
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On 2 Jan 2006 18:40:29 -0800, snipped-for-privacy@yahoo.com wrote:

Maybe they're expecting you to have 8 240V circuits. These take up 2 breaker slots, and have only one neutral and ground.
--
Mark Lloyd
http://notstupid.laughingsquid.com
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