Installing 100A subpanel off of 200A main panel.
Running #4 copper off a 100A breaker in main panel.
Where do I connect my #4 neutral conductor on the main panel? The neutral
bus bar is full, besides I don't think #4 cable would fit in those small
holes. Since the neutral and ground are bonded together in the main panel,
can I install a mechanical lug directly to the main panel (metal to metal)
and connect my neutral conductor to this? Would it have to be isolated?
Tying a neutral to the chassis would not be an ideal solution. Do you have a
common ground/neutral bus? If so, can you double or triple up grounds of the
same gauge into the same hole? Neutral wires cannot be doubled up. The only
other way to get more holes is to add a ground bus and screw it to the
(hopefully existing) holes in the panel chassis. Tie this into the
neutral/ground bus with a #4 or #6 copper wire and relocate all the grounds
to this bus. Hopefully, this frees up a bunch of holes in the neutral bus.
If none of those solutions work, you could split bolt it to the existing
neutral service wire or perhaps install a double lug where the neutral comes
in. Or lastly, take the largest neutral off the bus and put a 1/0 copper
wire segment in its place. Then split bolt the wire you took off and the new
#4 to this 1/0 segment. This segment with the split bolts must be properly
taped and colored white when you're done. You must make sure that common
wire has an ampacity equalt to the sum of all circuits that you split bolt
to it, or has the ampacity of the whole service (probably close to 200A
which means a 1/0 or 2/0 copper conductor).
Check the labels inside the panel's cabinet to see what size and
combination of wires will fit in the holes on the neutral buss bar. In
most of the panels I've seen the terminations will take two or three
Equipment Grounding Conductors (EGC) in one hole. Also most neutral
busses have larger terminations that will take number four American Wire
You could also install an additional buss bar and move the EGCs to that
bar thus clearing spaces on the Neutral Buss. It is a generally bad
practice to use the equipment cabinet as a regular current carrying
neutral conductor. Since the add on buss bar mounting screws bond it
directly to the cabinet and the Neutral Buss is bonded to the cabinet
via it's main bonding jumper they will both be electrically functioning
as bonded grounded conductor (neutral) buss bars but it will still be
better practice to move the EGCs to the new buss bar and leave the
identified grounded conductors on the original neutral buss bar. If you
find it necessary to use the new buss bar for current carrying grounded
conductors then install a bonding conductor between the buss bars.
If the neutral buss bar does not have terminations that will except #4
AWG conductors you can buy an add on lug that will attach to the buss
bar to accept that conductor.
Exactly what I wanted but didn't know they made such a thing. I went to the
Depot but couldn't find one. Until they directed me to the light bulb area.
Never thought to look there. Finally asked. Now if I double up a couple of
grounds I'll have 2 empty slots.
Kind of like Walmart. They have the rat poison next to the cat food. Which,
after thinking about it, is where it should be!!!!
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