A/C on one circuit causing voltage flicker on another (?)
 

This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks

A/C on one circuit causing voltage flicker on another (?)
 

On Jul 29, 1:46*am, wrote:
This winter I installed a 16-circuit subpanel and rewired the second
floor. *The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. *But these lights are on a different
circuit (same panel). *I did not expect this. *The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. *Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? *That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? *Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? *To be fair,
the flicker is subtle. *It's not huge, but it's there.

thanks

Duuuh , im pulllin to much , why am I pullun, my dick is small I need
a a whore or a diksuker, but I say get a HO or a lady sooo,

A/C on one circuit causing voltage flicker on another (?)
 

wrote in message

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal?

Your math is wrong. The AC is pulling many more amps momentarily during
startup, thus you get the dimming on other circuits. Very common.

A/C on one circuit causing voltage flicker on another (?)
 

wrote in message
...
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks

If the lights are flickering, you have a loose connection. If the lights are
dimming when a motor starts, it's normal

A/C on one circuit causing voltage flicker on another (?)
 

wrote in message
...
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks


The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected. Incidentally #6 wire is
only good for 50 amps. You should have used #4 for a 60 or 70 amp subpanel
feed.

A/C on one circuit causing voltage flicker on another (?)
 

On Jul 29, 7:05*am, "John Grabowski" wrote:
wrote in message

...





This winter I installed a 16-circuit subpanel and rewired the second
floor. *The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. *But these lights are on a different
circuit (same panel). *I did not expect this. *The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. *Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? *That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? *Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? *To be fair,
the flicker is subtle. *It's not huge, but it's there.

thanks

The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected. *Incidentally #6 wire is
only good for 50 amps. *You should have used #4 for a 60 or 70 amp subpanel
feed.- Hide quoted text -

- Show quoted text -

Technically, #6 wire is rated for 60 amps.

A/C on one circuit causing voltage flicker on another (?)
 

#4 could carry a 100 A subpanel.

s


"John Grabowski" wrote in message
...


The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected. Incidentally #6 wire is
only good for 50 amps. You should have used #4 for a 60 or 70 amp
subpanel feed.

A/C on one circuit causing voltage flicker on another (?)
 

A/C on one circuit causing voltage flicker on another (?)
 

A/C on one circuit causing voltage flicker on another (?)
 

#6 wire has about .00046 ohms/ft. Double that for return and call it 0.001
ohms/ft. Assume 50 ft of wire to subpanel means 0.05 ohms. Thus a 10 A
load would only drop about .5V. To test this get a digital voltmeter and
measure the voltage at a plug of interest. Plug a load like a toaster in
the other plug and see how much drop you get. Do this on both sides of the
240 circuit. If the drop is much more than calculated above then something
is amiss.


wrote in message
...
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks

A/C on one circuit causing voltage flicker on another (?)
 

wrote:
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks

I have same issue on rewired lake house. Friends in the business
tried to explain it - apparently not that unusual and no a lot
you can do either....

paul

A/C on one circuit causing voltage flicker on another (?)
 

Thanks everyone for the insights. I hadn't thought about the
increased load on startup and how that could be enough of a pull to
affect other circuits in the panel. I'll put my kill-a-watt on the A/
C and see if I can see what it draws during the startup (it might not
be fast enough to see, though).

To answer some questions:

If the lights are flickering, you have a loose connection. If the lights are
dimming when a motor starts, it's normal

I suppose technically it's a dim. I just wanted to distinguish it as
a very quick dimming (quick in that it dims down and then back up very
quickly) from what I used to have when the floor was all one 15A
circuit---back then the A/C would come on and everything would dim and
stay dimmed until the compressor shut off.

The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected.

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? I'll have to take a look and see
if that's indeed the case. Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

I did take out a permit. The inspector was great. We went over my
plans before I started, he came out early on before I'd finished rough-
in to make sure I was doing things correctly, then he checked the full
rough-in, then a final. He approved the #6 for 60A. As I recall it
rates for around 55A technically but the NEC allows you to round that
up. I also had a long thread on this group discussing the feeder wire
back then:
http://groups.google.com/group/alt.h...af96b1ca6205f6

The run is about 35' from the main. Part of the reason I wanted to go
with #6 was flexibility in getting from the basement to the attic.

Looking back at my old thread, it makes me realize I should probably
check and make sure I balanced the loads well on the two sides of the
panel. I meant to, but I'll double check.

Do this on both sides of the
240 circuit. If the drop is much more than calculated above then
something
is amiss.

Thanks for this. I'll try this out and see what I find. I'll also
look up Ohm's law...

A/C on one circuit causing voltage flicker on another (?)
 

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? *I'll have to take a look and see
if that's indeed the case. *Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

well, the A/C is on a different side of the panel as the lights I was
watching, so I guess it's enough to affect both sides of the panel. i
did do a good job of balancing loads (for example, there are two a/
c's, one on each leg).

A/C on one circuit causing voltage flicker on another (?)
 

Motor starting surge is approx 3x the running current....plus an
inductive "kick" for a capacitor start(single phase) motor.

A/C on one circuit causing voltage flicker on another (?)
 

"Steve Barker DLT" wrote in message
...
#4 could carry a 100 A subpanel.

s


"John Grabowski" wrote in message
...


The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected. Incidentally #6 wire is
only good for 50 amps. You should have used #4 for a 60 or 70 amp
subpanel feed.

6/3 Romex, copper, has a 60 degree rating of 55 amps. 4/3 Romex, copper has
a 60 degree rating of 70 amps. # 4 copper can only be used at a 100 amp
rating for service entrance and main feeder

A/C on one circuit causing voltage flicker on another (?)
 

wrote in message
...
Thanks everyone for the insights. I hadn't thought about the
increased load on startup and how that could be enough of a pull to
affect other circuits in the panel. I'll put my kill-a-watt on the A/
C and see if I can see what it draws during the startup (it might not
be fast enough to see, though).

To answer some questions:

If the lights are flickering, you have a loose connection. If the lights
are
dimming when a motor starts, it's normal

I suppose technically it's a dim. I just wanted to distinguish it as
a very quick dimming (quick in that it dims down and then back up very
quickly) from what I used to have when the floor was all one 15A
circuit---back then the A/C would come on and everything would dim and
stay dimmed until the compressor shut off.

The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected.

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? I'll have to take a look and see
if that's indeed the case. Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

I did take out a permit. The inspector was great. We went over my
plans before I started, he came out early on before I'd finished rough-
in to make sure I was doing things correctly, then he checked the full
rough-in, then a final. He approved the #6 for 60A. As I recall it
rates for around 55A technically but the NEC allows you to round that
up. I also had a long thread on this group discussing the feeder wire
back then:
http://groups.google.com/group/alt.h...af96b1ca6205f6

The run is about 35' from the main. Part of the reason I wanted to go
with #6 was flexibility in getting from the basement to the attic.

Looking back at my old thread, it makes me realize I should probably
check and make sure I balanced the loads well on the two sides of the
panel. I meant to, but I'll double check.

Do this on both sides of the
240 circuit. If the drop is much more than calculated above then
something
is amiss.

Thanks for this. I'll try this out and see what I find. I'll also
look up Ohm's law...

Just want to be sure, for balancing purposes, that you understand typical
panel buss is not left side on one leg and right side on the other. They
alternate in most panels

A/C on one circuit causing voltage flicker on another (?)
 

wrote in message
...
On Tue, 29 Jul 2008 14:49:19 GMT, Tony Hwang wrote:

wrote:
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks
Hi,
Two things, momentary starting surge current is much higher.
#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

What are you a building inspector, or FBI agent. It's none of your
****ing business if he got a permit or not. Permits do not make
wiring any safer.

Permits may not, but inspections do, especially if the work is being done
by non professionals... Chill

A/C on one circuit causing voltage flicker on another (?)
 

A/C on one circuit causing voltage flicker on another (?)
 

A/C on one circuit causing voltage flicker on another (?)
 

Jeff wrote:
#6 wire has about .00046 ohms/ft. Double that for return and call it 0.001
ohms/ft. Assume 50 ft of wire to subpanel means 0.05 ohms. Thus a 10 A
load would only drop about .5V. To test this get a digital voltmeter and
measure the voltage at a plug of interest. Plug a load like a toaster in
the other plug and see how much drop you get. Do this on both sides of the
240 circuit. If the drop is much more than calculated above then something
is amiss.


wrote in message
...
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks


Hi,
If you really want to do the test. Ordinary meter is too slow as well as
human eyes. Really oscilloscope is needed or a meter which can read the
instantaneous voltage and freeze the display.

A/C on one circuit causing voltage flicker on another (?)
 

wrote:
Thanks everyone for the insights. I hadn't thought about the
increased load on startup and how that could be enough of a pull to
affect other circuits in the panel. I'll put my kill-a-watt on the A/
C and see if I can see what it draws during the startup (it might not
be fast enough to see, though).

To answer some questions:

If the lights are flickering, you have a loose connection. If the lights are
dimming when a motor starts, it's normal

I suppose technically it's a dim. I just wanted to distinguish it as
a very quick dimming (quick in that it dims down and then back up very
quickly) from what I used to have when the floor was all one 15A
circuit---back then the A/C would come on and everything would dim and
stay dimmed until the compressor shut off.

The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected.

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? I'll have to take a look and see
if that's indeed the case. Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

I did take out a permit. The inspector was great. We went over my
plans before I started, he came out early on before I'd finished rough-
in to make sure I was doing things correctly, then he checked the full
rough-in, then a final. He approved the #6 for 60A. As I recall it
rates for around 55A technically but the NEC allows you to round that
up. I also had a long thread on this group discussing the feeder wire
back then:
http://groups.google.com/group/alt.h...af96b1ca6205f6

The run is about 35' from the main. Part of the reason I wanted to go
with #6 was flexibility in getting from the basement to the attic.

Looking back at my old thread, it makes me realize I should probably
check and make sure I balanced the loads well on the two sides of the
panel. I meant to, but I'll double check.

Do this on both sides of the
240 circuit. If the drop is much more than calculated above then
something
is amiss.

Thanks for this. I'll try this out and see what I find. I'll also
look up Ohm's law...

You might consider installing a "Kickstart"
hard start assist on your AC unit. It could
eliminate the light dimming.

http://www.kickstartoem.com/faqs/homeowner.html

[8~{} Uncle Monster

A/C on one circuit causing voltage flicker on another (?)
 

Uncle Monster wrote:
wrote:
Thanks everyone for the insights. I hadn't thought about the
increased load on startup and how that could be enough of a pull to
affect other circuits in the panel. I'll put my kill-a-watt on the A/
C and see if I can see what it draws during the startup (it might not
be fast enough to see, though).

To answer some questions:

If the lights are flickering, you have a loose connection. If the
lights are
dimming when a motor starts, it's normal

I suppose technically it's a dim. I just wanted to distinguish it as
a very quick dimming (quick in that it dims down and then back up very
quickly) from what I used to have when the floor was all one 15A
circuit---back then the A/C would come on and everything would dim and
stay dimmed until the compressor shut off.

The compressor may be pulling as much as 40 or 50 amps upon startup
which
would cause your other circuits to be affected.

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? I'll have to take a look and see
if that's indeed the case. Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

I did take out a permit. The inspector was great. We went over my
plans before I started, he came out early on before I'd finished rough-
in to make sure I was doing things correctly, then he checked the full
rough-in, then a final. He approved the #6 for 60A. As I recall it
rates for around 55A technically but the NEC allows you to round that
up. I also had a long thread on this group discussing the feeder wire
back then:
http://groups.google.com/group/alt.h...af96b1ca6205f6


The run is about 35' from the main. Part of the reason I wanted to go
with #6 was flexibility in getting from the basement to the attic.

Looking back at my old thread, it makes me realize I should probably
check and make sure I balanced the loads well on the two sides of the
panel. I meant to, but I'll double check.

Do this on both sides of the
240 circuit. If the drop is much more than calculated above then
something
is amiss.

Thanks for this. I'll try this out and see what I find. I'll also
look up Ohm's law...

You might consider installing a "Kickstart"
hard start assist on your AC unit. It could
eliminate the light dimming.

http://www.kickstartoem.com/faqs/homeowner.html

[8~{} Uncle Monster

OOPS! I just remembered you have a 120 volt
AC. Supco makes a hard start unit that will
work on your 120 vac air conditioner.

http://www.supco.com/eclass.htm

[8~{} Uncle Monster

A/C on one circuit causing voltage flicker on another (?)
 

On Jul 30, 4:38�am, Uncle Monster wrote:
Uncle Monster wrote:
wrote:
Thanks everyone for the insights. �I hadn't thought about the
increased load on startup and how that could be enough of a pull to
affect other circuits in the panel. �I'll put my kill-a-watt on the A/
C and see if I can see what it draws during the startup (it might not
be fast enough to see, though).

To answer some questions:

If the lights are flickering, you have a loose connection. If the
lights are
dimming when a motor starts, it's normal

I suppose technically it's a dim. �I just wanted to distinguish it as
a very quick dimming (quick in that it dims down and then back up very
quickly) from what I used to have when the floor was all one 15A
circuit---back then the A/C would come on and everything would dim and
stay dimmed until the compressor shut off.

The compressor may be pulling as much as 40 or 50 amps upon startup
which
would cause your other circuits to be affected.

Ok, so since this is a 120V A/C, I suppose I should only be seeing a
dim on other circuits that share that same side of the panel (e.g. the
same single hot wire from the main)? �I'll have to take a look and see
if that's indeed the case. �Or is the 40-50A 120V pull on one leg
enough to affect the other side of the panel?

#4 wire was better choice. Doing all this work, did you you take
out a permit? Just wondering. Where I live we need a DIY permit from
city and two inspections, during, after the work is done.

I did take out a permit. �The inspector was great. �We went over my
plans before I started, he came out early on before I'd finished rough-
in to make sure I was doing things correctly, then he checked the full
rough-in, then a final. �He approved the #6 for 60A. �As I recall it
rates for around 55A technically but the NEC allows you to round that
up. �I also had a long thread on this group discussing the feeder wire
back then:
http://groups.google.com/group/alt.h...hread/thread/8....

The run is about 35' from the main. �Part of the reason I wanted to go
with #6 was flexibility in getting from the basement to the attic.

Looking back at my old thread, it makes me realize I should probably
check and make sure I balanced the loads well on the two sides of the
panel. �I meant to, but I'll double check.

Do this on both sides of the
240 circuit. �If the drop is much more than calculated above then
something
is amiss.

Thanks for this. �I'll try this out and see what I find. �I'll also
look up Ohm's law...

You might consider installing a "Kickstart"
hard start assist on your AC unit. It could
eliminate the light dimming.

http://www.kickstartoem.com/faqs/homeowner.html

[8~{} Uncle Monster

OOPS! I just remembered you have a 120 volt
AC. Supco makes a hard start unit that will
work on your 120 vac air conditioner.

http://www.supco.com/eclass.htm

[8~{} Uncle Monster- Hide quoted text -

- Show quoted text -

another issue is the type of lights that are flickering....

those cheap shop fluroscents do flicker with even minor voltages
fluctuations.

had a rental with a tenant that bugged, afraid home had bad wiring .
replaced lamp fixtures with better ones end of trouble:)

A/C on one circuit causing voltage flicker on another (?)
 

Tony Hwang wrote:


Don't get upset. This is a fact. A house suffered a fire damage. Cause
was electrical. When insurance company found out some wiring was done
w/o permit, they refused to cover the damage. DIY permit does not cost
much. I know it is none of my business.

Do you have a citation of this? I keep reading these stories out here, but I've
never seen anything more this sort of third hand anecdotal evidence. I've read
over my homeowner's policy (Texas form HO-B) and I can't see anything that I
interpret would allow them to deny a claim on this basis.

Any further information would be appreciated.

Thanks,
Doug

A/C on one circuit causing voltage flicker on another (?)
 

Mike Copeland wrote:

Motor starting surge is approx 3x the running current....plus an
inductive "kick" for a capacitor start(single phase) motor.

Depends upon the motor and its load. Some are less. Compressors tend to be
a lot more. Check the nameplate on the AC. Look for "LRA".

Momentary dimming of lights on motor starting is quite normal.
If it is a 120V motor, the lights on circuits on the opposite
may brighten. Some lights are more sensitive to voltage
fluctuations: lights partially dimmed are much more noticeable;
full on incandescents are less noticeable.

A/C on one circuit causing voltage flicker on another (?)
 

"Douglas Johnson" wrote in message
...
Tony Hwang wrote:


Don't get upset. This is a fact. A house suffered a fire damage. Cause
was electrical. When insurance company found out some wiring was done
w/o permit, they refused to cover the damage. DIY permit does not cost
much. I know it is none of my business.

Do you have a citation of this? I keep reading these stories out here, but
I've
never seen anything more this sort of third hand anecdotal evidence. I've
read
over my homeowner's policy (Texas form HO-B) and I can't see anything
that I
interpret would allow them to deny a claim on this basis.

Any further information would be appreciated.

Thanks,
Doug

I too, have read this often on these newsgroups and yet I know in NY at
least, homeowner insurance policies protect homeowners against stupid things
that they do themselves. Possibly it differs elsewhere, but I've never seen
any proof of it

A/C on one circuit causing voltage flicker on another (?)
 

"Douglas Johnson" wrote in message
...
Tony Hwang wrote:


Don't get upset. This is a fact. A house suffered a fire damage. Cause
was electrical. When insurance company found out some wiring was done
w/o permit, they refused to cover the damage. DIY permit does not cost
much. I know it is none of my business.

Do you have a citation of this? I keep reading these stories out here, but
I've
never seen anything more this sort of third hand anecdotal evidence. I've
read
over my homeowner's policy (Texas form HO-B) and I can't see anything
that I
interpret would allow them to deny a claim on this basis.

Any further information would be appreciated.

Thanks,
Doug


I recently read my policy in detail and found this clause under
"Cancellation":

"Failure by the insured to comply with any Federal, State, or local fire,
health, safety, building, or construction regulation, law, or ordinance with
respect to an insured risk which substantially increases any hazard insured
against within 60 days of written notification of a violation of any law
regulation, or ordinance."

There is also another clause: "Increased hazard or material change in the
risk assumed which we could not have reasonably contemplated at the time of
assumption of the risk."

Take a closer look at your policy. Most likely your insurance company has
covered their ass somehow in the event of a disaster as a result of poor
craftsmanship.

A/C on one circuit causing voltage flicker on another (?)
 

In article ,
"John Grabowski" wrote:

I recently read my policy in detail and found this clause under
"Cancellation":

"Failure by the insured to comply with any Federal, State, or local fire,
health, safety, building, or construction regulation, law, or ordinance with
respect to an insured risk which substantially increases any hazard insured
against within 60 days of written notification of a violation of any law
regulation, or ordinance."

IOW, AIUI, you're covered unless and until you receive written
notification of violation, and fail to correct the problem within 60
days.

A/C on one circuit causing voltage flicker on another (?)
 

In article , RBM wrote:


If the lights are flickering, you have a loose connection. If the lights are
dimming when a motor starts, it's normal



Hmmm. Lights dimming. Blinking too (let's say).

One possible reason: light got dim enough that you can
see the 60-cycles (or would that be 120 both brights and
dims per second?).


David

A/C on one circuit causing voltage flicker on another (?)
 

In article ,
M Q wrote:
Mike Copeland wrote:

Motor starting surge is approx 3x the running current....plus an
inductive "kick" for a capacitor start(single phase) motor.

Depends upon the motor and its load. Some are less. Compressors tend to be
a lot more. Check the nameplate on the AC. Look for "LRA".

What does LRA stand for? An acronym? Name of a manufacturer?

Thanks,

David

A/C on one circuit causing voltage flicker on another (?)
 

Edwin Pawlowski wrote:
wrote in message
Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal?

Your math is wrong. The AC is pulling many more amps momentarily during
startup, thus you get the dimming on other circuits. Very common.


Yup!
Inductive load sarting surge can be pretty high for a split second eyes
can notice. Also main panel better be big enough as well to minimize the
effect. Peak surge is as high as 2.8 times of normal current draw.

A/C on one circuit causing voltage flicker on another (?)
 

David Combs wrote:
In article , RBM wrote:

If the lights are flickering, you have a loose connection. If the lights are
dimming when a motor starts, it's normal



Hmmm. Lights dimming. Blinking too (let's say).

One possible reason: light got dim enough that you can
see the 60-cycles (or would that be 120 both brights and
dims per second?).


David


Hmm,
Can you show here big initial reactive load (impedance) can change frequency
via math?

A/C on one circuit causing voltage flicker on another (?)
 

Mikepier wrote:
On Jul 29, 7:05 am, "John Grabowski" wrote:
wrote in message

...





This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.
Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:
-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit
So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).
So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.
thanks
The compressor may be pulling as much as 40 or 50 amps upon startup which
would cause your other circuits to be affected. Incidentally #6 wire is
only good for 50 amps. You should have used #4 for a 60 or 70 amp subpanel
feed.- Hide quoted text -

- Show quoted text -

Technically, #6 wire is rated for 60 amps.
Hi,
At what distance?

A/C on one circuit causing voltage flicker on another (?)
 

Jeff wrote:
#6 wire has about .00046 ohms/ft. Double that for return and call it 0.001
ohms/ft. Assume 50 ft of wire to subpanel means 0.05 ohms. Thus a 10 A
load would only drop about .5V. To test this get a digital voltmeter and
measure the voltage at a plug of interest. Plug a load like a toaster in
the other plug and see how much drop you get. Do this on both sides of the
240 circuit. If the drop is much more than calculated above then something
is amiss.


wrote in message
...
This winter I installed a 16-circuit subpanel and rewired the second
floor. The sub is fed from the main via a 60A 250v circuit over 6/3.
Everything has been working fine ever since, but I haven't really been
pulling much on these circuits until this week.

Today I'm noticing that when one of my window A/C's compressor kicks
on it is flicking the lights. But these lights are on a different
circuit (same panel). I did not expect this. The A/C is pulling
about 10A (120v) on a 20A dedicated circuit. Other power being drawn
from this panel includes:

-computer: ~5A on a dedicated 20A circuit
-computer and extras: ~5A on a dedicated circuit
-another A/C: ~8A on a dedicated circuit
-lights: ~? (1A maybe) on another circuit

So total I doubt I'm drawing more than 30A of 120V, so I can't be
maxing out the feed, right? That feed should give me 96A of 120V (80%
of 60A at 240V).

So what's the deal? Why would any lights on a different circuit
flicker when the compressor kicks on on another circuit? To be fair,
the flicker is subtle. It's not huge, but it's there.

thanks


Hi,
Your eyes and digital display panel is not good enought to catch it.
Digital scope or analog scope kinda instrument will show it proper.

A/C on one circuit causing voltage flicker on another (?)
 

On Thu, 28 Aug 2008 01:56:10 +0000 (UTC), (David
Combs) wrote:

In article ,
M Q wrote:
Mike Copeland wrote:

Motor starting surge is approx 3x the running current....plus an
inductive "kick" for a capacitor start(single phase) motor.

Depends upon the motor and its load. Some are less. Compressors tend to be
a lot more. Check the nameplate on the AC. Look for "LRA".

What does LRA stand for? An acronym? Name of a manufacturer?


That should be "Locked Rotor Amps", the maximum possible current
drain.

Thanks,

David