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questions on QO load center wiring

T

Texican

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I am replacing an old GE 125 amp load center with a new QO square D main breaker 200 amp panel
I have a fused disconnect between the meter and this new panel, so that makes the new panel a sub panel with a 4 wire feed and no bonding at this panel. neutral and grounds will be separate in this panel

I have never used a QO panel before and want to be sure the 4 feed in wires are correctly mounted its 4/0,4/0,4/0.2/0 AL

in the picture it looks like the 2/0 ground goes right next to the neutral wire. Is that correct ? looks like the neutral and ground lug are the same piece of metal, isnt that a bond that I do not want ?

my old GE panel needs a separate ground lug for 2/0 wire added to the ground terminals
like this one from QO, do I need this lug ? QO says its for neutral doesnt say ground ?

bottom line how to do a 4 wire into a qo panel ?

qopane;3.jpg
 
Isn’t there a ground bar in bottom left?

2/0 ground is oversized, you only have that size because SER can be used for both wye service conductors and 120/240 feeders, and the sizing of neutral for wye is much bigger than what is needed for ground

My guess is use a split bolt to reduce down to appropriate size and go into the ground bar in the bottom left background. That is assuming there is no 2/0 lug accessory you can install on the ground.
 
zanydroid said:
Isn’t there a ground bar in bottom left?

2/0 ground is oversized, you only have that size because SER can be used for both wye service conductors and 120/240 feeders, and the sizing of neutral for wye is much bigger than what is needed for ground

My guess is use a split bolt to reduce down to appropriate size and go into the ground bar in the bottom left background. That is assuming there is no 2/0 lug accessory you can install on the ground.
Click to expand...
Yup.
Screenshot_20231105-153041.jpg
 
Main concern with using the neutral lug for ground bar is that it may not be compatible, and may not be listed. Now while ground has relaxed demand on terminals, it’s probably cleaner to just use dual rated split bolt or other splicer to adapt it down. That for sure will be code compliant. And you can buy one at any store right now.
 
That one is copper only. Maybe bigger version of this:
www.homedepot.com

Southwire #14 STR - #1/0 STR Dual Rated Splicer (2-Pack) 65179540 - The Home Depot

Southwire splicers are used to connect and reduce conductors. This connector is dual-rated for use with copper and aluminum conductors. Specified for use with #14 STR - #1/0 STR Wire.
www.homedepot.com

I’m not 100% sure what is the right way to land a big ground. It’s possible the neutral lugs are fine (I might have used one myself), they probably don’t get labeled as ground lugs because you very rarely need a ground that size.

Next time I would probably use the lug if I remembered to order it since it looks nicer.
 
just to be clear. the 2/0 ground wire easily fits into the lug at the top next to the neutral lug.
but is this the correct lug if I dont want the N & G bonded ? looks like thew same piece of metal
can I use this neutral lug that QO sells and use it in the ground bar and attach my 2/0 ground wire there ?

qopanel4.jpg

qopane;3.jpg
 
Yeah I understood what you meant by being tempted to use that lug. But why be fixated to use something just because it fits? Electrically correct is first. That lug is probably there to allow undersized neutral installation or something…

Already specified in two posts above that you can attempt to use neutral lug if it fits, or a splice to reduce…
 
Texican said:
just to be clear. the 2/0 ground wire easily fits into the lug at the top next to the neutral lug.
but is this the correct lug if I dont want the N & G bonded ? looks like thew same piece of metal
can I use this neutral lug that QO sells and use it in the ground bar and attach my 2/0 ground wire there ?

View attachment 176281

View attachment 176283
Click to expand...
You should be able to add the separate lug.
Looking closer at your photo it appears there is a N/G bond from the factory that will have to be removed if you don't want the bond.

Edit - see clarity below from @timselectric
 
Last edited:
Texican said:
I have a fused disconnect between the meter and this new panel
Click to expand...
I don't think you can jump to this conclusion, it's a decision. I think there is a way to have a fused disconnect upstream of the main panel.

If you bond in the disconnect, then I guess that would be making the decision.
 
MisterSandals said:
Can you shed a little info on this? I did not know these (surge arrestor?) were connected like this. Connects to L1 and L2 and nothing else?

View attachment 177208
Click to expand...
timselectric said:
If you zoom in. You can barely see the ground wire connected to the bar behind the other wires.
Click to expand...
Correct. All 3 were cut to length to avoid lots of bends / loops. Iirc that was the recommendation in the manual. (yea I actually parsed through it)
 
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