Hi,

I'm confused about the very essense of a sub panel: is it just a
glorified junction box or can it actually increase the amount of
current that enters your house? For example, if I want to increase the
amount of current from 100amp to 150amps can I accomplish that with a
sub panel?

Thanks.

Aaron

"buffalobill's" short and sweet answer is correct.

What it does,basically, is gives you extra spaces for more breakers,so you
can run additional circuits. More or less an extension off of the main
panel.
The only way to increase the amount of
current that enters your house , or better said, the amount of current
available
to use in your house, is a service up grade.
New main panel, larger wire going to and coming from the electric meter, and
often times larger wire from the power company's transformer.
Tony

"buffalobill" wrote in message
...
On May 26, 3:46 am, Aaron Fude wrote:
Hi,

I'm confused about the very essense of a sub panel: is it just a
glorified junction box or can it actually increase the amount of
current that enters your house? For example, if I want to increase the
amount of current from 100amp to 150amps can I accomplish that with a
sub panel?

Thanks.

Aaron

no.

"Anthony Diodati" mrbreezeet1NO wrote in message
news:HCw_j.8087$9H6.6011@trnddc04...
"buffalobill's" short and sweet answer is correct.

What it does,basically, is gives you extra spaces for more breakers,so you
can run additional circuits. More or less an extension off of the main
panel.
The only way to increase the amount of
current that enters your house , or better said, the amount of current
available
to use in your house, is a service up grade.

Legally, it's possible to install a second "main" panel close by the orginal
service panel.

Things might have changed but not too many years ago it was permitted to
have up to six (6) service panels connected to one service.

With two "parallel" service panels you can easily do some "stuff." For
example, your "new" panel can be a type that incorporates a transfer switch.
If and when you get a generator, you can supply the "new" panel and transfer
those loads to the "new" panel when you may want to keep going when the
local grid is down. Other than that, the parallel panel only lets you
exceed the 42 breaker rule at the main service.

The advantage of a "sub" panel is that you can add circuits in, say, a new
wing or addition to your home and only run four (4) wires back to the main
service panel. If you servce a shop area, for example, you can clear
overload trips without having to walk back to the service panel.




** Posted from http://www.teranews.com **

Anthony Diodati wrote:
"buffalobill's" short and sweet answer is correct.

What it does,basically, is gives you extra spaces for more breakers,so you
can run additional circuits. More or less an extension off of the main
panel.
The only way to increase the amount of
current that enters your house , or better said, the amount of current
available
to use in your house, is a service up grade.
New main panel, larger wire going to and coming from the electric meter, and
often times larger wire from the power company's transformer.
Tony

I don't think it is quite that simple. Suppose you have 200 amp
service, and a panel that will accommodate only eight breakers, each
of which is occupied by a 15 amp breaker. Then the only way to access
the other 80 amps of capacity you already "have" is via a subpanel. It
doesn't really increase the capacity you have available, but it allows
you to access it. Adjust the numbers if you like, and argue about how
mis-designed my hypothetical situation might be, but the principle is
there.



"buffalobill" wrote in message
...

On May 26, 3:46 am, Aaron Fude wrote:

Hi,

I'm confused about the very essense of a sub panel: is it just a
glorified junction box or can it actually increase the amount of
current that enters your house? For example, if I want to increase the
amount of current from 100amp to 150amps can I accomplish that with a
sub panel?

Thanks.

Aaron

no.





--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

"CJT" wrote in message
...

I don't think it is quite that simple. Suppose you have 200 amp
service, and a panel that will accommodate only eight breakers, each
of which is occupied by a 15 amp breaker. Then the only way to access
the other 80 amps of capacity you already "have" is via a subpanel. It
doesn't really increase the capacity you have available, but it allows
you to access it. Adjust the numbers if you like, and argue about how
mis-designed my hypothetical situation might be, but the principle is
there.
That's a good point CJT, but is there really a lot or any 200 Amp mains,
that will only
hold eight breakers?
Still your point is valid.
Tony

On 2008-05-26, Aaron Fude wrote:

I'm confused about the very essense of a sub panel: is it just a
glorified junction box or can it actually increase the amount of
current that enters your house?

A panel is just a box to hold circuit breakers (overcurrent protection
devices, or OCPDs). The panel that holds the main shutoff for the
electrical service is called the main panel, and other panels are
called subpanels.

You can have all your breakers in the main panel if that is convenient
and you have enough space. Or you can use a subpanel if you need more
space for the breakers or it is more convenient. For example, if you
have 8 parallel circuits all running to your kitchen at the opposite
end of the house, it might be more convenient to have a subpanel near
the kitchen, run a single larger feeder circuit to the subpanel, and
then originate your kitchen circuits at the subpanel.

The other thing about panels is that the calculated demand of the
supplied loads from the panel should be less than the rating of the
feeder supplying the panel. So in the case of the main panel of a
house, the total demand of the house should be less than the rating of
your service conductors. Nothing you put downstream of the service
conductors can increase the rating of those service conductors; the
presence or absence of subpanels is immaterial.

Lastly, note that it is perfectly fine for the sum of the ratings of
the breakers in a panel to exceed the rating of the feeder for the
panel. Each of these ratings is a maximum and will seldom be
achieved.

For example, if you have 6 circuits rated at 20 amps in a panel
supplied by a 100 amp feeder, then you could run 5 of those circuits
at their full load of 20 amps as long as you like. If all 6 circuits
were at full load, then eventually the 100 amp breaker protecting the
feeder should trip (it won't be immediate). But in practice almost
never will all 6 of those circuits be at their full load--you might be
able to service a whole house with 40 circuits from a single 100 amp
feeder.

Yours, Wayne

Anthony Diodati wrote:
"CJT" wrote in message
...
I don't think it is quite that simple. Suppose you have 200 amp
service, and a panel that will accommodate only eight breakers, each
of which is occupied by a 15 amp breaker. Then the only way to access
the other 80 amps of capacity you already "have" is via a subpanel. It
doesn't really increase the capacity you have available, but it allows
you to access it. Adjust the numbers if you like, and argue about how
mis-designed my hypothetical situation might be, but the principle is
there.
That's a good point CJT, but is there really a lot or any 200 Amp mains,
that will only
hold eight breakers?
Still your point is valid.
Tony



First off adding up the ratings of the installed branch circuit Over
Current Protective Devices is not how you calculate how much of an
existing services ampacity is in use.

Second there are a hell of a lot of main lug only panels that have only
eight slots in them but the smallest breaker would have to be thirty
ampere for the panel to pass electrical inspection as service equipment.

It's important to realize that "sub panel is not a term that you will
find in the US NEC. A panel can be supplied by service entry
conductors, a feeder, the secondary conductors of a transformer, or a
local power source. Since the term itself is undefined it is difficult
to give you a good answer. I have converted multiple panel
installations to a larger service size by using a new main lug only
panel installed as service equipment to control the feeders that supply
each lighting and appliance or power panel but I doubt that is what you
had in mind.
--
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison