On Sat, 26 Jul 2003 09:16:28 -0500, "Dennis Spexet"
wrote:

I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.

I've been able to answer most of my questions from reading past messages, as
well as books I have on electrical wiring. However, there are a couple
questions that I've been wondering about:

1. Is a main lug panel actually required for the subpanel? Or can a main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.


For a sub-panel adjacent to the main panel, a main lug would suffice
(as it's" Main" would be the breaker in the main panel).

Only if the panel is a main panel without a prior or included main
disconnect would the 6 breaker rule be true. That rule more or less
states that if there is no disconnect from service, you can only have
up to 6 throws in the panel. Sine you are installing a subpanel with a
breaker in the main panel, that rule does not apply to your situation.

2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral. I'm not sure if the shielded cable is
OK for the ground, though. Also, is there any requirement for solid vs.
stranded cable, etc.?


Use conduit, with #2 THHN wire. At that size, the wire you will use is
stranded. Use wire intended for that situation, not just any wire you
have on hand (it may be unsuitable)

3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a conduit
is required. But since it's only a foot, I'm not sure.

Yes, unless you are using NM sheathed cable.

Thanks much in advance for your help!

-Dennis Spexet,

Use a hammerdrill

Use a hammerdrill

3. Is a conduit required, given the short distance (1 foot) between
the
two panels? If the subpanel was farther away, then I'd think that a
conduit
is required. But since it's only a foot, I'm not sure.

Yes, unless you are using NM sheathed cable.

Is conduit required if it is all in the wall, between two recessed boxes?

3. Is a conduit required, given the short distance (1 foot) between
the
two panels? If the subpanel was farther away, then I'd think that a
conduit
is required. But since it's only a foot, I'm not sure.

Yes, unless you are using NM sheathed cable.

Is conduit required if it is all in the wall, between two recessed boxes?

"Dennis Spexet" wrote in message
...
I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the
main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.

I've been able to answer most of my questions from reading past messages,
as
well as books I have on electrical wiring. However, there are a couple
questions that I've been wondering about:

1. Is a main lug panel actually required for the subpanel? Or can a
main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.

You can use either. In fact, if you're lucky, a 100A main breaker panel will
just be a main lug panel with a back fed breaker. You could remove this
breaker and clamp and put it in the main panel to protect the feeder.
Obviously, you'd have to buy a GE subpanel for this to work. If the main
breaker is larger and separate (i.e. won't fit the bus stabs), you'll have
to leave it in the panel. Just buy whichever is cheaper or has the number of
slots you require.

There is no requirement for number of disconnects in a subpanel unless it is
in a separate structure.


2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral. I'm not sure if the shielded cable
is
OK for the ground, though. Also, is there any requirement for solid vs.
stranded cable, etc.?

Perhaps you mean SE cable when you say shielded? You must have 3 insulated
conductors and one bare or green. The equipment grounding conductor only
need to be #8 in size. I'd stay with #2 for the hots and neutral.


3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a
conduit
is required. But since it's only a foot, I'm not sure.

Distance doesn't matter. You can either use a cable (SER, UF, NM) or
individual wires in conduit (THHN in PVC, flex, EMT...). If you use metallic
non-flex conduit, then it can take the place of your equipment grounding
conductor when properly bond both ends. If the boxes have concentric
knockouts, then you must use bonding type bushings. If using metal conduit,
you have to do this bonding anyway, so pick your poison...

--
Mark
Kent, WA

"Dennis Spexet" wrote in message
...
I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the
main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.

I've been able to answer most of my questions from reading past messages,
as
well as books I have on electrical wiring. However, there are a couple
questions that I've been wondering about:

1. Is a main lug panel actually required for the subpanel? Or can a
main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.

You can use either. In fact, if you're lucky, a 100A main breaker panel will
just be a main lug panel with a back fed breaker. You could remove this
breaker and clamp and put it in the main panel to protect the feeder.
Obviously, you'd have to buy a GE subpanel for this to work. If the main
breaker is larger and separate (i.e. won't fit the bus stabs), you'll have
to leave it in the panel. Just buy whichever is cheaper or has the number of
slots you require.

There is no requirement for number of disconnects in a subpanel unless it is
in a separate structure.


2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral. I'm not sure if the shielded cable
is
OK for the ground, though. Also, is there any requirement for solid vs.
stranded cable, etc.?

Perhaps you mean SE cable when you say shielded? You must have 3 insulated
conductors and one bare or green. The equipment grounding conductor only
need to be #8 in size. I'd stay with #2 for the hots and neutral.


3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a
conduit
is required. But since it's only a foot, I'm not sure.

Distance doesn't matter. You can either use a cable (SER, UF, NM) or
individual wires in conduit (THHN in PVC, flex, EMT...). If you use metallic
non-flex conduit, then it can take the place of your equipment grounding
conductor when properly bond both ends. If the boxes have concentric
knockouts, then you must use bonding type bushings. If using metal conduit,
you have to do this bonding anyway, so pick your poison...

--
Mark
Kent, WA

Dennis Spexet ) said...

I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.
[snip]

1. Is a main lug panel actually required for the subpanel? Or can a main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.

My comments are based on the CEC (Canadian Electrical Code, or more
specifically, the Ontario Electrica Safety Code, 23rd Edition).

No disconnect is required in the subpanel as the breaker in the main
panel serves as its disconnect. For your own convenince if the panel
were located in another part of the house, you may want a main breaker
in the panel.


2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral.

Here is where the CEC and NEC may differ. Under the CEC, #3 copper is
fine for 100 A overcurrent protection.

As for the ground, a 100 A service requires bonding to ground with
a #6 conductor, and this requirement holds true for the ground feeding
a 100 A subpanel.

3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a conduit
is required. But since it's only a foot, I'm not sure.

Conduit is fine. As for longer distances, 3/3 Romex is available (and,
incidently it has a #6 bare ground wire in it!). The Romex could be used
for the close-by panel, but conduit may look neater.

In the home we are building, we have a 100 A subpanel for the second
floor fed from the main panel with 3 #3 and a #6 ground through PVC
conduit. The electrical inspector was happy with it but warned that
if the building inspector had a problem with PVC conduit in the building,
we would have to replace it with 3/3 Romex.

He knew (as did I) that PVC conduit is not allowed in commercial buildings
or residential buildings over 6000 sq ft. I was unaware of a restriction
for smaller residences and he was unable to say if there was one. As it
turns out, PVC conduit is fine here. If it wasn't, there would be a lot
of people with central vacuum cleaners with problems as the pipe used
there is the same PVC (though with a much thinner wall) as PVC conduit.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove the capital letters!

Dennis Spexet ) said...

I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.
[snip]

1. Is a main lug panel actually required for the subpanel? Or can a main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.

My comments are based on the CEC (Canadian Electrical Code, or more
specifically, the Ontario Electrica Safety Code, 23rd Edition).

No disconnect is required in the subpanel as the breaker in the main
panel serves as its disconnect. For your own convenince if the panel
were located in another part of the house, you may want a main breaker
in the panel.


2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral.

Here is where the CEC and NEC may differ. Under the CEC, #3 copper is
fine for 100 A overcurrent protection.

As for the ground, a 100 A service requires bonding to ground with
a #6 conductor, and this requirement holds true for the ground feeding
a 100 A subpanel.

3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a conduit
is required. But since it's only a foot, I'm not sure.

Conduit is fine. As for longer distances, 3/3 Romex is available (and,
incidently it has a #6 bare ground wire in it!). The Romex could be used
for the close-by panel, but conduit may look neater.

In the home we are building, we have a 100 A subpanel for the second
floor fed from the main panel with 3 #3 and a #6 ground through PVC
conduit. The electrical inspector was happy with it but warned that
if the building inspector had a problem with PVC conduit in the building,
we would have to replace it with 3/3 Romex.

He knew (as did I) that PVC conduit is not allowed in commercial buildings
or residential buildings over 6000 sq ft. I was unaware of a restriction
for smaller residences and he was unable to say if there was one. As it
turns out, PVC conduit is fine here. If it wasn't, there would be a lot
of people with central vacuum cleaners with problems as the pipe used
there is the same PVC (though with a much thinner wall) as PVC conduit.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
-------------------------------------------------------------------------
NOTE: if replying by email, remove the capital letters!

"Dennis Spexet" wrote in message
...
I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the
main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.

I've been able to answer most of my questions from reading past messages,
as
well as books I have on electrical wiring. However, there are a couple
questions that I've been wondering about:

1. Is a main lug panel actually required for the subpanel? Or can a
main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.


You can put a 100 amp breaker in your main panel to protect the subpanel. A
hundred amp main in the sub is not required, but it does offer a little bit
more protection. A circuit breaker trips when it gets hot. The heat can be
caused from an overloaded circuit or from a loose connection within the
panel. A loose connection will arc when there is a load on the circuit and
generate heat. That heat from arcing could cause permanent damage to your
subpanel. If you have a main breaker in the subpanel in will sense the heat
sooner than the circuit breaker in the main panel and trip.



2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral. I'm not sure if the shielded cable
is
OK for the ground, though. Also, is there any requirement for solid vs.
stranded cable, etc.?


Number 2 is good for the current carrying conductors. You only need a
number 6 for your grounding conductor. As far as I know number 2 solid is n
ot available. It would be too difficult to work with. You could make the
neutral conductor number 1 since it does carry the load for both hots. This
is becoming more and more prevalent in commercial and industrial
installations as a result of neural conductors overheating from harmonics
caused by computers and other electronic equipment.




3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a
conduit
is required. But since it's only a foot, I'm not sure.



You can buy 1'' x 12'' (Or 1 1/4'' x 12'') galvanized nipples at an
electrical supply house (DO NOT use one from a plumbing supply). Get 4
locknuts and 2 bushings and install it between the two panels. It will look
neater and less subject to abuse. Conduit is not required. You could use
BX, MC, Romex, or Service Entrance cable. Use the correct connectors at
each end and use bushings on the connector.


Safety first.

John Grabowski
http://www.mrelectrician.tv




Thanks much in advance for your help!

-Dennis Spexet,

"Dennis Spexet" wrote in message
...
I've got a 200A GE loadcenter in my basement that has almost all of its
spaces used up (with 1/2" breakers), and so I want to install a subpanel.
In my installation, I would install a 100A subpanel, right next to the
main
panel (about a foot away). The subpanel would be connected to a 100A
double-pole breaker in the main panel.

I've been able to answer most of my questions from reading past messages,
as
well as books I have on electrical wiring. However, there are a couple
questions that I've been wondering about:

1. Is a main lug panel actually required for the subpanel? Or can a
main
breaker panel be used instead? From what I understand so far, either
kind can be used. I've also read that a disconnect mechanism of some kind
(main breaker) must be used if the subpanel contains more than 6 circuits.


You can put a 100 amp breaker in your main panel to protect the subpanel. A
hundred amp main in the sub is not required, but it does offer a little bit
more protection. A circuit breaker trips when it gets hot. The heat can be
caused from an overloaded circuit or from a loose connection within the
panel. A loose connection will arc when there is a load on the circuit and
generate heat. That heat from arcing could cause permanent damage to your
subpanel. If you have a main breaker in the subpanel in will sense the heat
sooner than the circuit breaker in the main panel and trip.



2. What kind of wiring should be used between the two panels? I was
planning on using four lengths of shielded #2 copper -- two for the hots,
and one each for ground and neutral. I'm not sure if the shielded cable
is
OK for the ground, though. Also, is there any requirement for solid vs.
stranded cable, etc.?


Number 2 is good for the current carrying conductors. You only need a
number 6 for your grounding conductor. As far as I know number 2 solid is n
ot available. It would be too difficult to work with. You could make the
neutral conductor number 1 since it does carry the load for both hots. This
is becoming more and more prevalent in commercial and industrial
installations as a result of neural conductors overheating from harmonics
caused by computers and other electronic equipment.




3. Is a conduit required, given the short distance (1 foot) between the
two panels? If the subpanel was farther away, then I'd think that a
conduit
is required. But since it's only a foot, I'm not sure.



You can buy 1'' x 12'' (Or 1 1/4'' x 12'') galvanized nipples at an
electrical supply house (DO NOT use one from a plumbing supply). Get 4
locknuts and 2 bushings and install it between the two panels. It will look
neater and less subject to abuse. Conduit is not required. You could use
BX, MC, Romex, or Service Entrance cable. Use the correct connectors at
each end and use bushings on the connector.


Safety first.

John Grabowski
http://www.mrelectrician.tv




Thanks much in advance for your help!

-Dennis Spexet,