RBM remove this wrote:

"John Ross" wrote in message
ups.com...


RBM remove this wrote:

"John Ross" wrote in message
ups.com...
Cutler Hammer Main Service Panel circa 1960.

Is anyone familiar with these main service panels from that time?

This is a 100 amp service with breakers.

I had some receptacles grounded by running the ground wires back to
panel. I had assumed these panels just had a neutral bus and
everything was put on that since there were not that many grounds.
Indeed, on the top is a horizontal bus that is basically a round piece
of copper (like a straw), and all the neutral/ground wires (incuding
main house ground) are wrapped around the bar--no screws.

I was surprised when I saw the electrician putting the new grounds on
another bus. This one is lower in the panel (also horizontal) and
looks like a flat peg board, but this had screws for connections. I
didn't get a good look, but it didn't look like there was any wires on
it.

Now that I am thinking about this, I am wondering if the two buses are
bonded.

In the late 60s or early 70s a central AC/Heater unit was added and
they used aluminum wire for it. So now I am wondering if it is more
likely that the bus bar with the screws was original or is it more
likely it was added when they did the Air conditioning wiring? I was
distracted so I am not sure, but I did see a piece of alumium wire
around there, but not sure if it was to the breaker or to that bar.

Anyway, has anyone seen this type of Cutler Hammer panel from 1960?
What would your take on this be? IF both buses were original, would
they have been bonded even though only the top one was used? If the
second was added, would the design be such that it would be bonded via
the case of the panel?

Obviously, I am new to this stuff, but I hope I was able to describe
it, even if I didn't use the correct terms.

--
John

I'm not exactly sure about your descriptions, however there was probably
only one neutral\ground buss in the panel. There should be a bonding
screw
or jumper attaching the box to the buss. Sometimes it's hard to see
through
all the wires. Another buss may have been added at a later date, which is
fine.

So you are saying that if it did originally just have that ONE buss,
it would have been connected (by screw or whatever) to the inside of
the PANEL? Is this required to ground the actual panel box?

Furthermore, if another bus was indeed added later, then all that was
necessary to bond the two was for the second one to make contact with
the metal of the panel?

--
John

The original buss bar is isolated. A bonding screw or jumper needs to be
installed to bond it to the box. This is done for a main service panel, but
not a sub panel. Unless you know what to look for and where to look, you may
not find it through all the wires. If an additional ground buss is added, it
gets screwed or bolted to the panel and becomes part of the grounding
system. If you want to connect neutral conductors to it as well, I would run
a substantial conductor from it to the original neutral buss


Not trying to get on your nerves.

You kinda lost me with the mention of the "grounding system". IF the
panel originally did just have the one bus, used for neutrals and
grounds (including main ground), would they have bonded it to the box
as you described? I'm still trying to understand if the panel box
itself is required to be grounded. Because, if it isn't, why would
they bother to bond this to the box (if there was no other bus bar)?

As far as the neutrals, none were added to that other bar--just the
new ground wires.

Can this all be determined at the *outlet* by someone if the correct
meters were used? In other words, all that has to be determined is if
there is a legitimate ground present (the neutrals are not an issue).
So if someone who knows what they were doing took a reading from H to
G (or whatever you suggest) at the outlet, would the readings (i.e.
volts) indicate there is or isn't a legitimate ground? Can that be
done?

Thanks!
--
John