Elec: Do you need to re-tighten Al service entrance cable?

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Mike O.

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Aug 12, 2003, 2:24:44 PM8/12/03
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Last May, I replaced/upgraded our service panel, meter base, etc. from
the 35 year old Federal Pacific 100A panel to a 200Amp SquareD Q0
series. The service entrance cable running down the house to the
meter pan, then to the service panel in the basement was replaced with
4-0 Aluminum SE cable. I used NoAlOx, worked into the conductors with
a stainless steel brush, and torqued the connections down to the value
listed on the panel and meter box. The lugs are rated for Copper or
Aluminum conductors.

I did get a permit, and the installation was inspected and approved
before the electric company re-attached the overhead lines.

Assuming I did everything correctly, once an aluminum service entrance
cable is installed, do the connections periodically need checked and
tightened? If so, would the two months since the installation be
enough for them to have worked loose? Everything else in the house is
copper; this is the first time I've worked with AL wiring.

The reason I'm asking is that a few times a day our lights flicker.
It's only a fraction of a second or so, the kind of effect you get
when something high current powers up (hair drier, etc.) It's similar
to, but much shorter than the effect when our A/C starts. It isn't a
consistent time and it doesn't seem to coorespond with any item in our
house starting up. I think it just started in the last couple of
weeks, but it may be that I just noticed it. They get dimmer, not
brighter, so I don't think it's a floating neutral. I've noticed it on
two or three different circuits.

There are several houses off of the same pole mounted transformer and
I'm going to check with the neighbors to see if they are experiencing
similar things. We moved in last fall, so we weren't here last
summer; it may be normal for our neighborhood when everybody's running
the A/C and stuff.

I've tried various newsgroup and web searches and have found some
info, but nothing that seems to fit my situation. Most of the
comments point either to a loose connection (which prompted this
message), the pole transformer, or the problems associated with
aluminmum wiring inside the house.

Since I just did the work recently, I wanted to try to eliminate all
that I could before I contact the power company.

Any suggestions would be appreciated.

Mike O.

John Grabowski

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Aug 12, 2003, 4:36:04 PM8/12/03
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My compliments. It sounds as though you did a nice job on your service
upgrade. I am happy to hear that you got a permit and had the job
inspected. If you had not replaced the Federal Pacific (AKA Fire Trap
Electric) panel I would have suggested that you start there.

A loose connection might be the problem. You could double check your work
in the service panel, but more likely you may have a loose connection
somewhere in your interior wiring. After 35 years don't expect everything
to be tight. You only need to torque down your aluminum service conductors
every few years.

Something else to consider at this time of year (Summer) are brownouts.
Your power company may be cutting back the volts a little to save their
equipment from overload.

I don't know what kind of appliances and equipment you have in your home,
but I have seen the same effect from office copy machines and laser
printers. I forget exactly what inside those machines causes that, but it
is a fairly well know trait. While they are on they do some sort of
internal cycling from time to time and it causes lights on the same circuit
to blink for a moment.

I suppose that it is possible if your neighbors had some high current
equipment going on and off that you would feel the effects. If that turns
out to be the case, then the power company may need to upgrade their
transformer feeding your house.

Also a loose connection at the transformer is possible and if your neighbors
have the same problem as you call the power company.


Good luck.

John Grabowski
http://www.mrelectrician.tv


"Mike O." <mso...@hotmail.com> wrote in message
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Mike O.

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Aug 13, 2003, 1:33:05 PM8/13/03
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Thank you for your kind words. It was definately a learning time. I
do computer network wiring and have done a bunch of basic electrical
work (adding circuits, outlets, etc.), but this was the first time I
tackled a full service upgrade. A comuple months of research, calls
to the inspector, etc. before the actual work. The inspector seemed
pretty impressed with the details, and I ended up saving $800.

The problem I'm seeing with the lights seems to be on multiple
cirucits, at least three. Assuming it is a branch cirucit problem,
why would it show up on three circuits? We have gas furnace and water
heater; I don't have any copiers or laser printers (BTW, it's the high
temp fuser that causes the load on those units. It rotates the
rollers so they don't overheat one area on the roller).

I figure I'll call the power company eventually, but I just wanted to
try to eliminate anything I can inside the house before I call them.

- Mike O.


"John Grabowski" <jgra...@optonline.net> wrote in message news:<Ucc_a.49725$_R5.17...@news4.srv.hcvlny.cv.net>...

John Grabowski

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Aug 13, 2003, 8:46:40 PM8/13/03
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It is refreshing to hear that a "Do-It-Yourselfer" did the homework
necessary to get the job done right. You should be an inspiration to those
contemplating projects.

Since the problem seems to be on multiple circuits, perhaps you should seek
a common denominator. Are those 3 circuits on the same phase from the
circuit breaker panel? Do any of those circuits share a neutral? Are there
several circuits in one junction box?

Something else I would check. Turn on as many lights and appliances as
possible at the same time. Leave them on for 30 minutes or so. Before
turning anything off, go to your electrical panel and listen carefully for
several minutes. It is not necessary to remove the panel cover. Listen for
any arcing from the main circuit breaker. Also feel the main circuit
breaker for any excessive heat. There is a slim possibility that you have a
defective main breaker.

If it turns out that the problem circuits are all on the same phase, I would
guess that the problem is somewhere along the power company's line from
their transformer down to the meter socket if it isn't the main breaker.

If you have the time and the inclination you should try keeping a log of the
events. For example: Time, date, outside temperature, rooms and circuits
affected, etc. This information could be checked with the power company's
record of brownouts or other disturbances. You could also compare notes
with your neighbors to see if there is a correlation.

Sometimes an electrician has to play detective to find the culprit.

I would be interested in hearing what the problem was after you get it
resolved.


John G.

Mike O.

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Aug 14, 2003, 12:41:56 AM8/14/03
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I had already checked the breakers for noise and heat, but didn't find
anything out of the ordinary. I hadn't tried with everything on, though.
The circuits don't have any interior wiring in common (shared neutral or
common box). I didn't think about checking if they're on the same 120V leg,
I'll look into that.

The log is a good idea, too; every little bit helps.

I'm leaning/hoping it's on the power company side. The neighborhood is at
least 35 years old, and the outside pole wires, transformers, etc. are
obviously not new. I'm wondering if the drops we're seeing are when other
high-current loads at other houses on the same transformer would power up.
The weather has been in the upper 80's with rain, so there's a lot of A/C
units running in the neighborhood. When our compressor starts, there's a
noticable dimming for about a 1/2 second; it seems reasonable that other
houses on the same transformer would also pull down the voltage when they
come on.

Again, the main worry I have is on the parts I did, especially the service
entrance connections since 1) I haven't worked with the alum wiring much
(and have seen all the horror stories), and 2) it's basically uncheckable
(for me) since I can't get into the meter pan. I'm reluctant to mess with
the two leads in the service panel while they're hot. I did check the
neutral in the panel, it seems tight and OK.


I'll let you know as the story unfolds...

Mike O.


"John Grabowski" <jgra...@optonline.net> wrote in message

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John Grabowski

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Aug 14, 2003, 10:13:25 AM8/14/03
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If aluminum wire is installed correctly it will provide you with trouble
free service. I am assuming that your service is overhead and not
underground. From the information that you provided it sounds as though
your installation was done right.

The problems that arise from aluminum wire are a result of its
characteristic to expand under load and contract with no load. Over a
period of time the expansion and contraction will cause the termination
point to loosen up. When the termination is loose it gets hot and can arc
with a load on it. The heat and arcing can cause the wire to melt and
damage the terminals. That is why it is a good idea to torque down your
connections every few years.

Copper expands and contracts also, but not as much as aluminum. Copper also
has a higher melting point than aluminum.

It could be time for the power company to upgrade their transformer. It may
have been installed before everyone in the neighborhood had air
conditioners.

You should compare notes with your neighbors. Also, if you make a serious
complaint to the power company, they could set up some monitoring equipment
on the line to see if the problem is a result of their equipment.


"Mike O." <msodo...@put-despam-in-decan.com> wrote in message
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Mike O.

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Sep 2, 2003, 9:57:43 PM9/2/03
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I've checked around, it seems this is a common occurance, especially during
summer. One neighbor who's lived here many years says that she was told
that the city upgrades the tranformers as they fail and that every once in a
while you hear one in the neighborhood blow and then they replace it with a
newer, higher capacity model.

I'm still going to contact the city electric division; who knows, maybe my
call will be the final one they need to do a replacement on our transformer?

- Mike O.


"John Grabowski" <jgra...@optonline.net> wrote in message

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Jdbeavers

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Jan 19, 2022, 11:45:11 PMJan 19
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I had a similiar problem and it was a poor connection from the power company's service drop to my service entrance wires. Power company replaced the wire connector and my problems were solved.

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