Hi,

I have a subpanel that is in a very convenient space and it is so very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a 2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is that so
and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a 2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel, simply to
prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the service
panel, which will limit the current that can be pulled from it, which I
can't determine, not knowing if it's feeder is aluminum or copper

RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is that so
and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a 2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel, simply to
prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the service
panel, which will limit the current that can be pulled from it, which I
can't determine, not knowing if it's feeder is aluminum or copper


The subpanel is fed by 2-2-2-2 copper.

"Aaron Fude" wrote in message
...
RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a 2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel, simply
to prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the
service panel, which will limit the current that can be pulled from it,
which I can't determine, not knowing if it's feeder is aluminum or copper
The subpanel is fed by 2-2-2-2 copper. Very strange that it would be fed
by 4-#2 conductors. Typically, #2 copper is good for 100 amps, which is
probably why the electrician recommends not exceeding half the service
maximum on it

On Jul 24, 7:18 pm, "RBM" wrote:
"Aaron Fude" wrote in message

...

RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a 2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel, simply
to prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the
service panel, which will limit the current that can be pulled from it,
which I can't determine, not knowing if it's feeder is aluminum or copper
The subpanel is fed by 2-2-2-2 copper. Very strange that it would be fed
by 4-#2 conductors. Typically, #2 copper is good for 100 amps, which is
probably why the electrician recommends not exceeding half the service
maximum on it


I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was installed
for the pool eqpt and run off one of the two 150A main panels.
That sub panel had passed local inspection and is more that 50% of the
main.

wrote in message
...
On Jul 24, 7:18 pm, "RBM" wrote:
"Aaron Fude" wrote in message

...

RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so
very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is
that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a
2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel,
simply
to prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the
service panel, which will limit the current that can be pulled from
it,
which I can't determine, not knowing if it's feeder is aluminum or
copper
The subpanel is fed by 2-2-2-2 copper. Very strange that it would be
fed
by 4-#2 conductors. Typically, #2 copper is good for 100 amps, which is
probably why the electrician recommends not exceeding half the service
maximum on it


I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was installed
for the pool eqpt and run off one of the two 150A main panels.
That sub panel had passed local inspection and is more that 50% of the
main.

Your friend has a 300 amp service split between two "main" panels. The pool
sub panel fused at 80 amps is not greater than half the size of the main
panels. The OP has a 200 amp service, a 100 amp sub panel, and seems to be
asking if he can pull 125 amps on it

RBM wrote:

I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was
installed for the pool eqpt and run off one of the two 150A main
panels. That sub panel had passed local inspection and is more that 50%
of
the main.

Your friend has a 300 amp service split between two "main" panels.
The pool sub panel fused at 80 amps is not greater than half the size
of the main panels. The OP has a 200 amp service, a 100 amp sub
panel, and seems to be asking if he can pull 125 amps on it

I live in what was orginally a duplex. Each side was equipped with 200-Amp
service.

By the simple expedient of adding a door to the common wall, I converted the
building to a single-family residence. Bingo! I have 400-Amp service split
between two main panels.

Is it your position I can now put a 175-Amp sub-panel off of one of the main
panels because such would not exceed 50% of the total power delivered to the
building?

"HeyBub" wrote in message
m...
RBM wrote:

I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was
installed for the pool eqpt and run off one of the two 150A main
panels. That sub panel had passed local inspection and is more that 50%
of
the main.

Your friend has a 300 amp service split between two "main" panels.
The pool sub panel fused at 80 amps is not greater than half the size
of the main panels. The OP has a 200 amp service, a 100 amp sub
panel, and seems to be asking if he can pull 125 amps on it

I live in what was orginally a duplex. Each side was equipped with 200-Amp
service.

By the simple expedient of adding a door to the common wall, I converted
the building to a single-family residence. Bingo! I have 400-Amp service
split between two main panels.

Is it your position I can now put a 175-Amp sub-panel off of one of the
main panels because such would not exceed 50% of the total power delivered
to the building?


My position is nothing of the kind. As gfretwell pointed out, you can
install a 200 amp sub panel if you like. My recommendation is just to
install your heaviest loads on the main panel, which will have the largest
feeder, and lessen the dimming affect of the heavy loads

wrote in message
...
On Sun, 26 Jul 2009 09:14:15 -0400, "RBM" wrote:


wrote in message
...
On Jul 24, 7:18 pm, "RBM" wrote:
"Aaron Fude" wrote in message

...

RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so
very
temping to put a lot of stuff on it (kitchen /includes 30amp stove
+
garage + central A/C + etc), but my electrician told me that it's
not
proper to draw more than half the amperage from the main panel. Is
that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a
2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping
that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the
total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel,
simply
to prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the
service panel, which will limit the current that can be pulled from
it,
which I can't determine, not knowing if it's feeder is aluminum or
copper
The subpanel is fed by 2-2-2-2 copper. Very strange that it would be
fed
by 4-#2 conductors. Typically, #2 copper is good for 100 amps, which
is
probably why the electrician recommends not exceeding half the
service
maximum on it


I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was installed
for the pool eqpt and run off one of the two 150A main panels.
That sub panel had passed local inspection and is more that 50% of the
main.

Your friend has a 300 amp service split between two "main" panels. The
pool
sub panel fused at 80 amps is not greater than half the size of the main
panels. The OP has a 200 amp service, a 100 amp sub panel, and seems to be
asking if he can pull 125 amps on it


The real answer will come from a load calculation. Nothing else
matters. You can install a 200a sub panel on a 200a service if you
want, the code is silent on it.

What are the loads on that current service?

2ga cu is good for 115a so you can put a 125a breaker on it using the
round up rule.

240.4(B) Devices Rated 800 Amperes or Less. The next higher standard
overcurrent device rating (above the ampacity of the conductors being
protected) shall be permitted to be used, provided all of the
following conditions are met:
(1) The conductors being protected are not part of a multioutlet
branch circuit supplying receptacles for cord-and-plug-connected
portable loads.
(2) The ampacity of the conductors does not correspond with the
standard ampere rating of a fuse or a circuit breaker without overload
trip adjustments above its rating (but that shall be permitted to have
other trip or rating adjustments).
(3) The next higher standard rating selected does not exceed 800
amperes.

wrote in message
...
On Sun, 26 Jul 2009 09:14:15 -0400, "RBM" wrote:


wrote in message
...
On Jul 24, 7:18 pm, "RBM" wrote:
"Aaron Fude" wrote in message

...

RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so
very
temping to put a lot of stuff on it (kitchen /includes 30amp stove
+
garage + central A/C + etc), but my electrician told me that it's
not
proper to draw more than half the amperage from the main panel. Is
that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a
2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping
that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the
total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel,
simply
to prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in the
service panel, which will limit the current that can be pulled from
it,
which I can't determine, not knowing if it's feeder is aluminum or
copper
The subpanel is fed by 2-2-2-2 copper. Very strange that it would be
fed
by 4-#2 conductors. Typically, #2 copper is good for 100 amps, which
is
probably why the electrician recommends not exceeding half the
service
maximum on it


I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was installed
for the pool eqpt and run off one of the two 150A main panels.
That sub panel had passed local inspection and is more that 50% of the
main.

Your friend has a 300 amp service split between two "main" panels. The
pool
sub panel fused at 80 amps is not greater than half the size of the main
panels. The OP has a 200 amp service, a 100 amp sub panel, and seems to be
asking if he can pull 125 amps on it


The real answer will come from a load calculation. Nothing else
matters. You can install a 200a sub panel on a 200a service if you
want, the code is silent on it.

What are the loads on that current service?

2ga cu is good for 115a so you can put a 125a breaker on it using the
round up rule.

240.4(B) Devices Rated 800 Amperes or Less. The next higher standard
overcurrent device rating (above the ampacity of the conductors being
protected) shall be permitted to be used, provided all of the
following conditions are met:
(1) The conductors being protected are not part of a multioutlet
branch circuit supplying receptacles for cord-and-plug-connected
portable loads.
(2) The ampacity of the conductors does not correspond with the
standard ampere rating of a fuse or a circuit breaker without overload
trip adjustments above its rating (but that shall be permitted to have
other trip or rating adjustments).
(3) The next higher standard rating selected does not exceed 800
amperes.



Unless it's 2/3 Romex. It's not at all clear to me, what he's run to the
sub. I know he said 2222 copper, but that doesn't make sense either.

wrote in message
...
On Sun, 26 Jul 2009 14:20:39 -0400, "RBM" wrote:


wrote in message
. ..
On Sun, 26 Jul 2009 09:14:15 -0400, "RBM" wrote:


wrote in message
...
On Jul 24, 7:18 pm, "RBM" wrote:
"Aaron Fude" wrote in message

...

RBM wrote:
"Aaron Fude" wrote in message
...
Hi,

I have a subpanel that is in a very convenient space and it is so
very
temping to put a lot of stuff on it (kitchen /includes 30amp
stove
+
garage + central A/C + etc), but my electrician told me that it's
not
proper to draw more than half the amperage from the main panel.
Is
that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a
2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 181 94

which I guess is saying that the max amps is 94, but I'm hoping
that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the
total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

I would recommend running your heavy loads off of the main panel,
simply
to prevent lights dimming due to the smaller feeder (#2 vs. 4/0)

If this is an existing sub panel, it will have a main breaker in
the
service panel, which will limit the current that can be pulled
from
it,
which I can't determine, not knowing if it's feeder is aluminum or
copper
The subpanel is fed by 2-2-2-2 copper. Very strange that it would
be
fed
by 4-#2 conductors. Typically, #2 copper is good for 100 amps,
which
is
probably why the electrician recommends not exceeding half the
service
maximum on it


I don't know the code specific answer to how many amps you can draw
off a main panel, but I can tell you this. In a 4 year old house
here, I just finished helping a friend add a new line for a new
irrigation well. We hooked it to an 80A sub panel that was installed
for the pool eqpt and run off one of the two 150A main panels.
That sub panel had passed local inspection and is more that 50% of the
main.

Your friend has a 300 amp service split between two "main" panels. The
pool
sub panel fused at 80 amps is not greater than half the size of the main
panels. The OP has a 200 amp service, a 100 amp sub panel, and seems to
be
asking if he can pull 125 amps on it


The real answer will come from a load calculation. Nothing else
matters. You can install a 200a sub panel on a 200a service if you
want, the code is silent on it.

What are the loads on that current service?

2ga cu is good for 115a so you can put a 125a breaker on it using the
round up rule.

240.4(B) Devices Rated 800 Amperes or Less. The next higher standard
overcurrent device rating (above the ampacity of the conductors being
protected) shall be permitted to be used, provided all of the
following conditions are met:
(1) The conductors being protected are not part of a multioutlet
branch circuit supplying receptacles for cord-and-plug-connected
portable loads.
(2) The ampacity of the conductors does not correspond with the
standard ampere rating of a fuse or a circuit breaker without overload
trip adjustments above its rating (but that shall be permitted to have
other trip or rating adjustments).
(3) The next higher standard rating selected does not exceed 800
amperes.



Unless it's 2/3 Romex. It's not at all clear to me, what he's run to the
sub. I know he said 2222 copper, but that doesn't make sense either.


I don't think they even make #2 RX and if this was SER the EGC would
not be #2.
I was assuming THHN/THWN in pipe.

I hear ya. I've used 2/3 Romex, but where I am, I can't get copper SER, or
SEU for that matter, and of course the ECG would be smaller, which is why I
question what the OP actually has. The OP says, " The sub-panel is 18ft away
from the main panel and is fed by a 2-2-2-2 wire. Clearly, unclear

On Sun, 26 Jul 2009 14:20:39 -0400, "RBM" wrote:

[snip]

Unless it's 2/3 Romex. It's not at all clear to me, what he's run to the
sub. I know he said 2222 copper, but that doesn't make sense either.


Wasn't it 2-2-2-2? 4 wires, all 2-gauge copper?

"Sam E" wrote in message
...
On Sun, 26 Jul 2009 14:20:39 -0400, "RBM" wrote:

[snip]

Unless it's 2/3 Romex. It's not at all clear to me, what he's run to the
sub. I know he said 2222 copper, but that doesn't make sense either.


Wasn't it 2-2-2-2? 4 wires, all 2-gauge copper?

Here is what he wrote: " The sub-panel is 18ft away
from the main panel and is fed by a 2-2-2-2 wire.


Often, when people say wire, they mean cable. Since he's writing in the
singular, "a 2-2-2-2 wire", my assumption is that he means cable, however,
as gfretwell points out , there isn't any such cable. At this point, only
the OP can clarify

On Jul 24, 6:11*pm, Aaron Fude wrote:
Hi,

I have a subpanel that is in a very convenient space and it is so very
temping to put a lot of stuff on it (kitchen /includes 30amp stove +
garage + central A/C + etc), but my electrician told me that it's not
proper to draw more than half the amperage from the main panel. Is that
so and what's the rational for it.

The sub-panel is 18ft away from the main panel and is fed by a 2-2-2-2
wire. I found this table

WG gaug Maxamps for chassis Maximum amps for power transmission
2 * * * 181 * * 94

which I guess is saying that the max amps is 94, but I'm hoping that
that's a rating for 100ft and I can go to about 125 over 18ft.

So I guess there are two questions in one:
1. Can I draw 125 amps on the basis that it's more that 1/2 the total
service (200amps)?
2. Can I draw 125 amps on the basis that it's 2-gauge wire?

Thanks

Aaron

Aaron
The term Sub Panel is not found in the National Electric Code. I
don't know if your electrician is talking about what he/she believes
to be good practice or what they believe is a code issue. The most
accurate way to differentiate a "Sub Panel" from the Service Equipment
for code purposes would be to call it a Feeder Supplied Lighting and
Appliance Panel Board. Several manufacturers make feed through lug
panels that are listed by a testing laboratory as "Suitable for use as
Service Equipment. These panels have a main breaker and a set of main
lugs, usually at opposite ends of the buss bars. They are designed to
pass most of the current that comes through the main breaker into a
feeder that is attached to the feed through lugs. One very common use
for such panels is to provide a main breaker and a few load breakers
on the outside of a home while moving the homes lighting and appliance
panel board to a place within the home were the wire runs to the loads
will be shorter.

As another poster has already opined much depends on the calculated
load. If the calculated load is less than the ampacity of the feeder
conductors then I cannot see were that would be wrong. Please
remember that even though the code allows you to use a 125 ampere
breaker to protect a number two copper feeder it would be dammed
foolishness on your part to load it past it's rated ampacity of 115
amperes if it is #2 THHN in conduit or 95 Amperes if it is run in Non
Metalic Sheathed Cable.
--
Tom Horne