Ground, Neutral Connections in Main Panel

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Old 10-13-06, 12:49 PM
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Ground, Neutral Connections in Main Panel

I read somewhere (maybe here) that each ground or neutral connection in my house's breaker panel should have only one wire to it. I don't ever recall seeing it any other way in the houses I've owned over the years.

I just bought another house, built in 1959. It has 100-amp service, and the panel has an electrical inspector's sticker on it dated 1996 (I'm guessing that was when the house was rewired). Anyway, every ground and neutral connection has at least two wires to it, and several have three or four. I had the home inspected before buying, and the inspector didn't mention this. Is it something that used to be done but now isn't? I suspect it's been that way for 10 years.
 
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Old 10-13-06, 01:25 PM
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Unless the bar is rated for the number of wires in each hole it is a violation since its installation. Most bars are only listed for no more than 2 grounding conductors of the same size. Neutral connections were limited to one per hole. This was contained in the manufacturers instructions. Only recently has the Code had something that addressed this directly.

You should be able to buy auxillary ground bars for your panel to more the grounds to and allow the neutrals to be properly terminated on the neutral buss.

Older panels did not have as many buss connections as todays panels. I get the feeling that your panel may be overcrowded. How many breakers are in your panel and how many is it rated for?
 
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Old 10-13-06, 01:27 PM
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The requirement is that neutral wires must be landed one wire per screw; no exceptions, although this is a fairly new rule so old panels have multiples. Ground wires of the same gauge may be doubled or tripled as per the panel manufacturer's instructions.
 
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Old 10-28-06, 02:00 PM
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Originally Posted by pcboss
Unless the bar is rated for the number of wires in each hole it is a violation since its installation. Most bars are only listed for no more than 2 grounding conductors of the same size. Neutral connections were limited to one per hole. This was contained in the manufacturers instructions. Only recently has the Code had something that addressed this directly.

You should be able to buy auxillary ground bars for your panel to more the grounds to and allow the neutrals to be properly terminated on the neutral buss.

Older panels did not have as many buss connections as todays panels. I get the feeling that your panel may be overcrowded. How many breakers are in your panel and how many is it rated for?
How can a panel be overcrowded? It has slots for 20 breakers. It has 17 though three are double-pole and thus all 20 slots are filled.
 
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Old 10-28-06, 07:48 PM
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One way of overcrowding a 20 slot panel is to put tandem breakers in - two half size breakers in one slot. Do you have any of those?

So, are there sufficient neutral and grounding connections for 20 circuits in this panel? i.e. at least 20 neutral bar screws and 10 groundbar screws? i.e. did the installer double up unnecessarily (in which case you can probably fix it), or is the panel mysteriously short of neutral / grounding connections?

What make of panel is it?

Cheers,

Sy
 
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Old 10-29-06, 02:31 PM
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Yes, there is one tandem breaker. Each half supplies a single outlet for a 110v window air conditioner. These were apparently added after the house was built since both windows where the air conditioners are mounted have two duplex outlets below them.

The panel is a Square D; the breakers are type QO. There are ten groundbar screws but also only ten neutral bar screws.
 
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