Which I'm sure you'd agree is an interesting concept. By diversity
I assume they mean that the statistical probability of someone
putting 100A of load all on one leg is low. I think we all agree,
low, but it's not zero.
Which is cool if it's a fixed installation of some known equipment.
But it could be a house where someone could plug in a bunch of
resistance heaters and have them by chance wind up on the
I agree. That was my first suggestion and everyone agrees
it's 100% kosher. Use the new ground bar
for grounds, move some existing grounds from the neutral/ground
bar over to it, thereby freeing up more neutrals.
What are your thoughts about what I pointed out about
current flow through the panel itself? If you put a ground bar
on the other side of the panel, it's bonded to the panel.
Even if you connect it with a heavy wire back to the
original neutral, you still will have current dividing, with
some of it going through the panel metal. I would think the
better option would be to install an insulated neutral bar.
On 4/30/2013 10:25 AM, firstname.lastname@example.org wrote:
A #4 wire with 75 degree insulation has a rating of 85A. With 60 degree
insulation the rating is 70A. They can be used as 100A service (for
residential only) and feeders downstream from that service.
That is because of "diversity". Large loads (range, water heater, ...)
will cycle on and off. If they are all on and draw 100A now they will
cycle off soon.
I would still rather use a ground bar for ground wires. The neutral
should have at least enough positions for neutrals for the number of
poles allowed in the panel.
You are right about current flow through the panel as an alternate path.
All this assumes a service panel with a N-G bond. For a subpanel the
alternate path is the ground conductor back to the service, which is a
On 4/30/2013 2:32 PM, email@example.com wrote:
Doesn't matter what the insulation is. You can use #4 for a residential
Connections (lugs, terminals, ...) have a temperature rating. The rating
is based on the current rating of a conductor with insulation of that
temperature. That limits the amount of heat at the connection
contributed by the wire.
If you have a breaker that is rated for 75 degree C and you are using
wire with a 90 degree C insulation, you can only use the wire at the
current rating for a 75 degree wire. (The wire has a higher current
rating at 90 degrees C.) If you had a bare wire you can only use it at
the current rating for a 75 degree insulated wire.
For circuits of 100A and less, in general connections are only rated for
the current allowed for a 60 degree wire unless the connection is
explicitly rated different. (110.14-C)
If any heat sink modifies conditions it is up to the manufacturer and UL
to determine a higher temperature rating for the connection.
Well I guess if you have more ground wires than you have
ground terminals, then you "have to". It's either that or go to
all the added trouble of adding another ground bus. And I
don't see it having anything to do with neatness and
organization. You can put two wires into one terminal neatly.
Or you could put two wires into two terminals and make it
a mess. If two are allowed, I would do it.
The new final answer on this is that it turns out that Siemens does in fact
have a "neutral bar kit" that it now sells to enable people like me to add a
second neutral bar to the panel that I have that only came with one neutral
The one for my panel is Siemens catalog/part number ECCNB16.
Here is a link to the ECCNB16 Instruction Sheet which shows this neutral bar
kit and how to install it:
Apparently, this is a new item that Siemens now sells. And, it turns out
that on the Page 21 of the Siemens website that I posted in my original post
(at the very bottom of the page, on the right), there are two "neutral bar
kits" listed, but there is a typo and the catalog/part numbers that are
shown are incorrect. Siemens sent me an email letting me know that the
correct catalog/part number for the item that I needed is ECCNB16.
When I went to local electrical supply places near me, they didn't have them
in stock and they weren't familiar with the neutral bar kit that I needed.
And, since it is new, it wasn't listed in the Siemens catologs/brochures
that they had. But, I showed them a copy of the ECCNB16 Instruction Sheet
that I had and they were able to order the part using that catalog/part
number. It arrived yesterday and I'll be installing it today.
One other note is that the electric supply place that I went to said that
when Siemens switched over to their ES Series and PL Series load centers a
few years ago, most of the electricians that the supply place deals with say
they do not want the ES Series load centers -- in part due to the lack of a
second neutral bar on ES Series panels with 24 or less circuits.
I know now that I should have specified that I wanted the PL Series panel
when I had mine installed. Apparently, the PL Series is better quality and
has a copper busbar, and they all come with two neutral bars, etc.
Thanks for the update. And good to see you found a
solution. Kind of amazing that the help line at Siemens couldn't
figure this out day one.
One question. Is this neutral bar insulated from the panel metal
or in direct contact with it? My guess would be that it's insulated,
so that no current flows in the panel metal.
You're right, it is kind of amazing that they didn't figure it out on day 1.
I have a hunch that Siemens created these new lines of load centers a few
years ago, and maybe the idea of only including one neutral bar in certain
models was something that they introduced at the same time. Then (I'm just
guessing here), maybe it took a couple of years for them to think that they
should give people the option of adding back the "missing" neutral bar. So,
I think their "neutral bar kit" was just recently introduced by them and not
everyone in the company knew about it yet. And, to make things more
complicated, they have the wrong catolog/part number for that item on their
What happened was that after I received the first "final answer" from them
saying that they did not have an offering of a way to add a neutral bar, I
wrote back and asked what the "neutral bar kits" that I found on their
website were for. That's when they realized that they do now have that
option available, and they wrote back about what the neutral bar kit is and
said it would work, and gave me the correct part number and a copy of the
And, yes, the added neutral bar is insulated from the panel itself. It
snaps into place on the left side on top of an existing plastic backing that
keeps it insulated from the panel. The cross bar connects the original
neutral bar to the second (newly added) neutral bar. The original neutral
bar has a bonding screw that can be used to bond it to the panel (which
makes it also a ground bar), or I think that screw can be backed out to keep
it as just a neutral bar that is not grounded. In the latter case, separate
ground bars can be added to the panel, and they are made to screw directly
into the panel itself.
Incidentally, the neutral bar kit that I bought costs about $20. I actually
bought 3 of them because I had 3 main load centers installed at the same
time -- one for each of 2 apartments and one for a house panel. I probably
could have gotten the PL Series load centers which include two neutral bars
for about the same price that I ended up paying for the panels I have plus
adding the neutral bar. I don't know for sure because I haven't checked the
prices, but that's my guess.
I do like Siemens panels, but now I know that the next time that I have them
put in I'll need to specify which panel I want -- meaning the PL Series that
has a copper busbar, two neutral bars, etc.
I just received another email from the Siemens rep today. He said that he
checked again with their product management people and they told him,
".... the ES load centers have been recently re-designed & now will be
including the second neutral bar in all the 2020, 2024, & 2424 load
I think that's a smart move on their part.
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