upgrade of service panel

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Relect

Member
Location
California
I am planning to upgrade a service panel. In the past I have always done this from a new wall so there were no issues with wires or getting to the circuits.
This time I need to replace an existing panel. I would like to pull the existing circuits out of the old box and move them to the new box however the wires are not long enough. I do not want to break into walls and find the first Jbox in the chain the replace the wire and the old service is in such poor shape that I do not want to use is as a subpanel.
This must come up all the time with service panel replacements or upgrades.
Question, how do you extend the individual circuits to get the extra 3 to 5 feet of wire to connect to the new service?
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
One way: Pull out the panel and replace in the same place. Extend via splice, any wires too short to reach their new position. Customer will have no power until you're done, but the service mast/conduits can be reused

Another way: Put a new panel next to the existing one with new service conduits or mast. Use old panel as a giant J box, ripping out the busing when done (you may need to bolt the door closed unless you block off the all the openings where breakers used to be). Use a few short fat nipples from old panel to new so you can stuff it full and not worry about fill or thermal derating. Allows you to work more at your own pace until the Service is switched. Then you need to splice and extend everything to the new panel.

I also did a variant of the last where the new Service went 30' away from the existing one and on a different floor. Installed all the new panels and a bunch of branch circuit cables were run close to the original service. Switched over to new panels, installed all the pre-run cables into the old panel which became a J box. As time went on, more and more circuits got re-run from the new service and removed from that old one. I've now been able to remove that old service box and replace it with a 6x6x4 J box with only about 5 circuits in it.
 

Relect

Member
Location
California
So the "splice" is in the new main box? Just pushed off to the side out of the way? You can do that? just splice all the Hot, Neutral and grounds, as needed? Are there specific types of splices that are required?

If I do have to place the new box in a slightly different location, then it is "legal" to use the existing panel as a giant J-box and put all the splices there?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
So the "splice" is in the new main box? Just pushed off to the side out of the way? You can do that? just splice all the Hot, Neutral and grounds, as needed? Are there specific types of splices that are required?

If I do have to place the new box in a slightly different location, then it is "legal" to use the existing panel as a giant J-box and put all the splices there?
You can use the old panel as a splice box if you wish
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
What kind of construction do you have? Is there a crawl space below and attic above? Somewhere you will have to splice these wires if they are not long enough.
 

John120/240

Senior Member
Location
Olathe, Kansas
So the "splice" is in the new main box? Just pushed off to the side out of the way? You can do that? just splice all the Hot, Neutral and grounds, as needed? Are there specific types of splices that are required?

If I do have to place the new box in a slightly different location, then it is "legal" to use the existing panel as a giant J-box and put all the splices there?

Wire nuts are one of the most common splicing methods & yes they are legal to use in a panel. Some electricians consider their panels

to be works of art and would consider wire nuts in the panel an abomination. However the electricity doesn't care about appearances.

The only ones to care would be anal electricians and after the cover is put on who cares.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
There seem to be a lot of people who think you can't splice in a panel and I don't know where that myth started unless it was considered poor workmanship. You can as long as you don't exceed a certain amount of butter fill (I think it is 75%). Pretty hard to exceed 75% fill in most panel gutters, although my house panel is a mess because the previous "electrician" left much of the Romex jacket on the cable for 6 or 8 inches in the panel before terminating or splicing it. Technically, the gutter isn't 75% full by calcualtion, but there are so many stiff and abandoned cables that running any more would be difficult.
 

bobbymari

Senior Member
Location
los angeles ca
There seem to be a lot of people who think you can't splice in a panel and I don't know where that myth started unless it was considered poor workmanship. You can as long as you don't exceed a certain amount of butter fill (I think it is 75%). Pretty hard to exceed 75% fill in most panel gutters, although my house panel is a mess because the previous "electrician" left much of the Romex jacket on the cable for 6 or 8 inches in the panel before terminating or splicing it. Technically, the gutter isn't 75% full by calcualtion, but there are so many stiff and abandoned cables that running any more would be difficult.

my first boss told me it was against code wayyyyy back when , I wasnt confident enough to question him. As long as you are under the fill requirements splice away
 

bobbymari

Senior Member
Location
los angeles ca
I am planning to upgrade a service panel. In the past I have always done this from a new wall so there were no issues with wires or getting to the circuits.
This time I need to replace an existing panel. I would like to pull the existing circuits out of the old box and move them to the new box however the wires are not long enough. I do not want to break into walls and find the first Jbox in the chain the replace the wire and the old service is in such poor shape that I do not want to use is as a subpanel.
This must come up all the time with service panel replacements or upgrades.
Question, how do you extend the individual circuits to get the extra 3 to 5 feet of wire to connect to the new service?

sounds like your best scenario would be to turn existing lemme guess (zinsco) panel into a jbox and extend circuits circuits to your new panel. If its a nightmare in there make sure to mark your phases correctly. This is a very comman method especially when replacing old fuse boxes
 

John120/240

Senior Member
Location
Olathe, Kansas
sounds like your best scenario would be to turn existing lemme guess (zinsco) panel into a jbox and extend circuits circuits to your new panel. If its a nightmare in there make sure to mark your phases correctly. This is a very comman method especially when replacing old fuse boxes

Identifying phases in a residental panel is meaningless if you ask me. What I would be worried about is any two wire situations where

the white wire was used as a hot. Older range, dryer,or A/C applications come to mind. When moving circuits from the old panel to the

new panel it is important to match the wht & blk to the correct wht & blk. Or wht, blk, & red to wht, blk, & red.

I hope that makes sense.
 

PetrosA

Senior Member
Identifying phases in a residental panel is meaningless if you ask me. What I would be worried about is any two wire situations where

the white wire was used as a hot. Older range, dryer,or A/C applications come to mind. When moving circuits from the old panel to the

new panel it is important to match the wht & blk to the correct wht & blk. Or wht, blk, & red to wht, blk, & red.

I hope that makes sense.

It can be very important if the house has K&T in it. Marking neutrals is also helpful when dealing with old wiring that's all one color - dirty.
 

John120/240

Senior Member
Location
Olathe, Kansas
Identifying phases in a residental panel is meaningless if you ask me. What I would be worried about is any two wire situations where

the white wire was used as a hot. Older range, dryer,or A/C applications come to mind. When moving circuits from the old panel to the

new panel it is important to match the wht & blk to the correct wht & blk. Or wht, blk, & red to wht, blk, & red.

I hope that makes sense.

Since your doing all of this work now is a good time to identify what these different circuits are. Take a short piece of romex jacket,

& use a sharpie on the jacket then slip the romex over the hot at the breaker.
 

bobbymari

Senior Member
Location
los angeles ca
Identifying phases in a residental panel is meaningless if you ask me. What I would be worried about is any two wire situations where

the white wire was used as a hot. Older range, dryer,or A/C applications come to mind. When moving circuits from the old panel to the

new panel it is important to match the wht & blk to the correct wht & blk. Or wht, blk, & red to wht, blk, & red.

I hope that makes sense.

ill send you some pictures of fried neutrals due to improper residential phasing
 

bobbymari

Senior Member
Location
los angeles ca
by the sound of original post on methods of installing a panel just wanted to give some good practice advice, yea i was more speaking of circuitry more than incomming
 
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