Electrical Engineering - New Electrical Service Box Question

Author

New Electrical Service Box Question

Robert11

2006-04-16, 12:21 pm

Hello:

Moved into an older home that has 100 amp service.

Will be hiring an electrician to update it to 150 or 200 amps, but would
like
to get some comments and information on how to handle the following problem,
before I do so.

The present service box is recessed into an area that does not have the
physical
room to accept a larger box. Not practical to cut a larger opening there.

However, plenty of room about six feet away.

But, all the wires coming in for the 25 or so circuits do not have the
length to
make it to a new, six foot distant, location.

What are some options in handling this, please ?

If new extension pieces of wire are just spliced onto the old wires using
wire-nuts, these nuts can't be just left
dangling in space, can they ?

Or, if they are all packed into the old box (e.g., with the breaker panel
removed) it
probably violates some codes as to the number of wire nuts in a given volume
(or does it ?)

How would / should this type of problem normally be handled ?

Thanks,
Bob

Dale Farmer

2006-04-16, 1:21 pm

Robert11 wrote:
> Hello:
>
> Moved into an older home that has 100 amp service.
>
> Will be hiring an electrician to update it to 150 or 200 amps, but would
> like
> to get some comments and information on how to handle the following problem,
> before I do so.
>
> The present service box is recessed into an area that does not have the
> physical
> room to accept a larger box. Not practical to cut a larger opening there.
>
> However, plenty of room about six feet away.
>
> But, all the wires coming in for the 25 or so circuits do not have the
> length to
> make it to a new, six foot distant, location.
>
> What are some options in handling this, please ?
>
> If new extension pieces of wire are just spliced onto the old wires using
> wire-nuts, these nuts can't be just left
> dangling in space, can they ?
>
> Or, if they are all packed into the old box (e.g., with the breaker panel
> removed) it
> probably violates some codes as to the number of wire nuts in a given volume
> (or does it ?)
>
> How would / should this type of problem normally be handled ?
>
> Thanks,
> Bob
>
>
When your electrician comes in to do the pre-work inspection, he
should discuss all these options with you, and let you know what they are.

--Dale

electrician@electrician2.com

2006-04-16, 3:21 pm

<<Moved into an older home that has 100 amp service.

Will be hiring an electrician to update it to 150 or 200 amps, but
would
like
to get some comments and information on how to handle the following
problem,
before I do so.

The present service box is recessed into an area that does not have the

physical
room to accept a larger box. Not practical to cut a larger opening
there.

However, plenty of room about six feet away.

But, all the wires coming in for the 25 or so circuits do not have the
length to
make it to a new, six foot distant, location.

What are some options in handling this, please ?

If new extension pieces of wire are just spliced onto the old wires
using
wire-nuts, these nuts can't be just left
dangling in space, can they ?

Or, if they are all packed into the old box (e.g., with the breaker
panel
removed) it
probably violates some codes as to the number of wire nuts in a given
volume
(or does it ?)
How would / should this type of problem normally be handled ? >>

The old panel can be converted into a junction box. The breaker panel
should be removed. The old circuits can be extended to the new panel
by splicing in the old panel using wire nuts. A cover is required for
the old panel and it must be accessible (cannot be placed behind
permanently installed building materials.) A good guide on box fill
requirements is: 2 cubic inches for No. 14, 2.25 cubic inches per No.
12, 2.5 cubic inches for No. 10, 3.0 cubic inches for No. 8, and 5.0
cubic inches for No. 6. Where two wires are spliced they are counted
as two wires. Also the grounding conductors are all counted as one
conductor using the largest wire size. For instance two No. 14's
spliced require 4 cubic inches of space in the splice box. More than
likely, the panel has plenty of space. If there is not enough space
an extension ring for the panel may be required. This can be
constructed out of sheet metal. A cover is required: the wire nut
splices cannot be left dangling in space. Some hard line inspectors
will require a listed junction box and not allow you to build or modify
your own. However, it is common practice in industrial locations to
modify boxes using sheet metal, etc. The new panel should have a work
space of at least three feet in front and 6 ft. 6 inches high. For
extending the circuits you can use the same cable sizes or place the
wires in conduits. Remember is over 3 current carrying conductors are
used in a raceway they are require to be derated. Use 90 degree
insulation (THWN-2 for out doors and THHN for indoors) rated conductors
and install no more than 9 in a raceway and this should not be a
problem. Also do not fill raceways to more than 40 percent. Do not
extend circuits using open single conductors - this is not allowed.
They must be in a cable or raceway. These are some of the rules that
may guide you.

ehsjr

2006-04-17, 2:21 am

Robert11 wrote:
> Hello:
>
> Moved into an older home that has 100 amp service.
>
> Will be hiring an electrician to update it to 150 or 200 amps, but would
> like
> to get some comments and information on how to handle the following problem,
> before I do so.
>
> The present service box is recessed into an area that does not have the
> physical
> room to accept a larger box. Not practical to cut a larger opening there.
>
> However, plenty of room about six feet away.
>
> But, all the wires coming in for the 25 or so circuits do not have the
> length to
> make it to a new, six foot distant, location.
>
> What are some options in handling this, please ?
>
> If new extension pieces of wire are just spliced onto the old wires using
> wire-nuts, these nuts can't be just left
> dangling in space, can they ?
>
> Or, if they are all packed into the old box (e.g., with the breaker panel
> removed) it
> probably violates some codes as to the number of wire nuts in a given volume
> (or does it ?)
>
> How would / should this type of problem normally be handled ?
>
> Thanks,
> Bob
>
>

Five options come to mind, in no particular order:
1) Don't upgrade
2) Rewire from the new service to the first junction on
each branch
3) Pull the cables from the existing service to the attic
or basement, and splice new runs from the new service
to them in as many j-boxes as are needed.
4) Splice them in the existing service which you convert
to a j-box
5) Install new service and feed old service from it
as a sub-panel.

I'm guessing that 5) may be your best bet. If necessary,
one or two existing circuits could be routed to the new
service.

Ed

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