Panelboard wiring questions

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  #1  
Old 02-17-05, 08:25 AM
ruckertt
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Question Panelboard wiring questions

I need to add two 20A branch circuits to my existing panel. The current layout of my panel has a single ground bar with the neutral wires together and the ground wires together neatly arrayed in sections along the bar, with two wires secured per each set screw location. It just happens that the "ground wire" section has no open holes to secure the new ground wires, although there are several holes available in the "neutral' wire section.

Is it acceptable to secure a third ground wire in a hole that already has two wires there. Is there any restriction on securing a 12- and 14-gage wire in the same location on the bar? Or should I just forget about how things are grouped and just terminate my new ground wires in open holes next to the existing neutral wires?

Also, all of the existing cables come into the panel through the top of the box. Is there any restriction against using a knock-out on the side of the box for the new cables?
 
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Old 02-17-05, 08:44 AM
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ruckert,

If the bus is compliant to mutliple wires then it is considered acceptable to put (2) Ground wires under one terminal screw( of the same size only ) on the bus bar but no more than (2) and only (1) on the neutral per terminal screw on the bus bar. However, it is only acceptable if the busbar is approved for this and listed as such.

However, in your case ( if the panel in question is the MAIN PANEL ) and is not a sub panel( ie: remotly located somewhere other than right at the meter base entrance ) then you can use the wires where the neutral are for your terminations keeping in mind the rules I have stated above.

The neutrals and Grounds are basically on the same Bus Bar in a main panel and not seperated however with a NEAT electrician it may look as if they are....the key point is here it has to be the MAIN panel for the house.

Now as for going out of the panel, if their are knockouts on the side you can certainly use them with no problems as that is what they are their for.

It is also imporatant to note that the NEC says in 110-14 that the bus bar must be listed as such for multiple wires. What brand of panel do you have would help out more at getting to the problem.

Hope this helps...let us know how the project goes.
 

Last edited by ElectricalMan; 02-17-05 at 09:03 AM.
  #3  
Old 02-17-05, 09:22 AM
ruckertt
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Panelboard wiring...

Yes, a very neat electrician did the work on my main panel. A place for everything, and everything in its place... The box is a Westinghouse panel with a part number (this is on the panel layout sticker) of B20 3040 C. I don't have any paperwork for it other than the sticker.

As it is now, the neutrals are actually paired-up in the terminals, just like the grounds. This is contrary to what you stated, if I understood correctly. It would seem that insufficient space exists to permit single wire terminations per location (not enough holes).

It sounds like I can use any hole on the bus bar for terminating either grounds (up to 2 like wires) or neutrals (question whether 1 or 2 allowed, although plenty of paired terminations are currently installed).

Can you clarify "use the wires where the neutral are for your terminations" ? Do you mean that grounds and neutrals (of like gage) can be terminated at the same screw, or that grounds and neutrals can be terminated in locations next to each other (but separate screws).

Thanks for your input.
 
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Old 02-17-05, 09:59 AM
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What I am saying is that it is for the most part considered acceptable ( if listed as such ) to place (2) grounds of the same AWG ( Wire Guage ) in the same terminal bus screw as long as they are also of the same material...(ie: dont put a aluminum wire in with a copper wire and so on ).

I can't comment on what the previous electrician has done and many still do it as I have seen some Inspectors be a stickler for it and others dont mind..but when we are teaching it we personally use the rule of thumb....

(1) Neutral per hole in BusBar and (2) Grounds per hole in BusBar as long as they are of the same AWG and Material ( ie: copper )

The code article for the listings of mutliple connections is 110-14(a), In all this the Code is very clear that the terminals must be identified as allowing ,mutliple wires in them...the above is simply the rule we and many other electricians use.

In your case, if the panal was inspected and it was approved and has multiple wires under the same screw set bus bar connections then I think you would be fine....just use the rule I listed above to minimize the issues of it....

What I am trying to do here is give you simply a option..if someone here says...NO..by all means you can't do that.....I would say...what are your options...if the panel was inspected and it was approved and so on...you are simply adding a circuit to it and if you keep the rule above in mind you should be fine.

Again to clarify......do not mix Neutrals with Grounds.....but they do share the SAME busbar in your panel....so using the rule listed and what is in your panel you should notice of the doubled up ones it should not have a white and bare in the same hole.......I do not like the idea of putting more than one wire in a hole but in some cases you are stuck...as in yours...chances are if it was inspected and not back in the OLD DAYS...then the electrician was approved and it was fine......just never put multiple wires of different sizes under the same screw set....Use the rule in YOUR case only..not to everyone....(1) white wire MAX per busbar hole..and up to (2) of the grounded bare of the same AWG ( wire size ) per bus bar hole.....again pushing it as the 1999 NEC says the bar needs to be labeled as such and allowed......but we are assuming here the electrician knew this when installed the panel and complied and knew what he/she was installing and inspected.
 
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Old 02-17-05, 10:25 AM
ruckertt
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Panelboard wiring...

Ok, got it - thanks for the definitive clarification...
 
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