Hi everyone,
Iam upgrading the wiring in my house and am moving the location of my new circuit breaker panel. The wiring to the existing panel will not reach the location of the new panel, can I connect the old wiring to the new panel via a junction box in the ceiling?
Thanks,
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Replies
Are you referring to the load wires in the old panel? If so, they can be spliced in a box that remains accessible and extended to the new panel. The NEC limits the number of conductors in boxes based on the space[ in cubic inches] that is available. In other words, make sure your box is big enough or use several smaller boxes.
I am referring to the load wires in thye old panel. I want to splice them in a junction box in accessible ceiling space. Can anyone tell me the max. amount of wires allowed in a 666inch junction box.Thanks.
Assuming that your wires are all the same size[12 ga.], the code requires 2.25 cubic inches per conductor. The code counts each wire that enters the box and is spliced there as one conductor. So, a 12-2 romex entering and leaving would count as 4 conductors and need 9 cubic inches of space.[4X2.25=9] No allowances need to be made for locknuts or bushings. There is a special rule concerning equipment grounding conductors.I quote"Where one or more equipment grounding conductors enter a box, a single volume allowance in accordance with Table 314.16[B] shall be made based on the largest equipment grounding conductor or equipment bonding jumper present in the box"
This means that if you are splicing two 12-2w/G cables, they are counted as 5 conductors for box fill calculation purposes.
I hope you understand that there is not a short answer to your question. A 6x6x6 box would yield 216 cubic inches . Each #12 conductor needs 2.25 Cubic inches . If we assume that you are splicing cables with grounds to cables with grounds, each cable splice would consume 5X2.25 cubic inches for a total of 11.25 per splice. With a total volume available of 216, I calculate that you cuuld splice 19 cables in the box with a little space left over.
I have assumed that you were splicing 12 gauge romex cables. If you are using 14 gauge wire each conductor requires 2.00 cubic inches of space.
In the real world, you probably have a combination of sizes . Use good judgment and don't assume that the box is not full if you can cram more in it. Space is needed to disapate heat.
Hope this helps.
By the way, my quotes are from the 2002 National Electrical Code, Article314
Thanks,
Your reply was very helpful - now I have one more question.
My branch circits are original from 1956 and have two conductors and no ground, when i splice the circuits in the junction box is the lack of grounds on existing circuits (I am running alot of new circuits which will be grounded but will not be in the Junction box.) cause me any problems? What do I do with the grounds from the new cables in the J-Box? I will Be using 12ga. for my splices, I think that my existing circuits are mostly 12ga. In my native country of Australia it is legal to step down from 12 to 14ga. but not legal to step up so to speak, does that rule apply in the US?Thanks again.
You will have no problems when you splice as long as you remember that the two wire cable served loads are not grounded. Tie the ground wires from your new cables to the metal j-boxes. Code requires all metallic parts of the system to be bonded to ground.
You might consider that there is no time like the present to go ahead and run the grounded cable all the way to at least the first connection point on the circuit. Sometimes it will be quite a bit of trouble to fish the wires, but you will be grounded and have a better overall job.
You can splice 14 to 12 . The important thing to remember is that 14 gauge wire needs to be on a breaker no larger than 15 amps. 20 amp breakers are ok for #12 wire. So, if you leave the new panel with #12 and splice it to #14 at a J-box,it must still be protected by a 15 amp breaker. Those circuits that are all #12 can go on the 20 amp breakers.
Where are you at? Could you fill in your profile and let us know? I've tried to be pretty generic in my answers but local codes prevail.
Chuck
If you don't wish to keep the existing panel in place and use it as a junction box you can still use the enclosure as a junction box for connections. Mounted it anywhere you can get most of the cables to in good order. A single large box is faster than many small ones.You do need to install closures or plates to fill any holes opened up by removal or knockouts that are no longer used. In an attic or crawl space there isn't any need to make it look pretty. Steel 4x4 blank plates can be pressed into service to plate over large holes, like where the conduit coming from the meter was. TEK screws make it go quickly.Even a small panel, converted by removing the guts and screwing the cover closed has enough room to legally accommodate any likely number of conductors. Be sure to ground the box.Around most shops there is a collection of panel enclosures kept for this sort of situation. Sometimes obsolete or unavailable panel covers, replacement buss bars and insulators also.
IBEWchuck is correct. However, if you are talking about the service wires (the ones from the pole to the main) I do not believe those can be spliced. Someone with more knowledge is sure to chime in...
On the service side a conduit, sized for the conductor sizes and observing wire fill, run from the meter to the new location makes sense. Depending on the distance and local code and/or AHJ you may need to install a fused disconnect after the meter.
Unless the distance is very small and the route well protected this is still a good idea IMHO. These conductors, after the meter but before the first point of disconnect, are unfused and so if shorted they have to blow clear. Even if the AHJ doesn't require it it is the way to go.
On the branch circuit side typically the best solution is to convert the existing panel into a junction box and run conduit/s to the new location to get the existing circuits into the new panel. One honking big juction box is a lot easier than mounting a lot of small junction boxes.
Watch the conduit fill and derate properly for the number of conductors. Also look at the ambient temperature where you run the conduit. Once the calculations are completed and one or two conduits run, you can use flex if it makes getting the conduit in more easily, pulling in wires and terminating is easy.
Running cables is another way. You would need one cable per circuit but if the panel only has a couple of circuits and running a conduit is going to be a pain it may be the way to go.
Helps if you keep the existing ground bar in the panel so you only need to run one ground. Usually a single #8 does it but go with the largest existing.
The existing panel gets the door screwed shut and it can be painted over or otherwise disguised as long as it remains accessible without damaging finished surfaces or removing building structure.
The service entrance conductors from the meter won't reach or the branch circuit conductors from the panel to your house won't reach? If the service entrance conductors won't reach you may have a question that can't be adequately answered with out seeing what you've got.
Here are some things to consider if in fact you are asking about the SEC's:
Ideally these wires would not be spliced.
They should be checked for proper size, as they might not even be the right size for your old service.
If they are aluminum they should probably be replaced.
If you need to splice them, check your local codes. Some jurisdictions have max distances from the meter to the main.
The NEC specifies a max of ten feet of SEC the house that is unfused.
You could put a main disconnect next to the meter or some where else to meet these above mentioned requirements and run fused(protected) conductors to the new panel location. If you do this you may want to as least consult with a local electrician or inspector.If you haven't drawn blood today, you haven't done anything.
"The NEC specifies a max of ten feet of SEC the house that is unfused."Is that new in the 2002 or 2005?All that I have seen is 230-70 (1999) that say accessible location either outside or inside "nearest" the point of entry.
Man, I can't find it. I started out in the trade with the '96 NEC and a may be mixing up the NEC with our city code. The requirement used to be that service entrance conductors could not pass through more than ten feet of raceway from the point they entered a building to the overcurrent device.
The current city code is that you are allowed no more then ten feet of conductor from the meter to the overcurrent device regardless of the location(inside or outside or combination.) This results in load centers being nearly back to back with the meter or the installation of a main disconnect near the meter and feeders run from the main to the load center.
I have to admit this is safer than twenty feet of EMT with unprotected SEC's running across the basement ceiling. I like the rule. Guys used to get by the old rule by running the 20 feet of conduit on the outside of the house and poking through into the back of the load center. That was sooooo ugly. Oh, and under the basement slab or through a crawl space was not considered "inside the house".
If this is in the code, or was, would someone tell me so I don't continue to dwell on this.If you haven't drawn blood today, you haven't done anything.
The "ten foot rule" isn't in the NEC, and never was.
The issue is addressed by a local reqirement, or by policies set by the inspector. Yea, I know, any requirement ought to be set fourth in written form, but often the inspector has to interpret the NEC. With no local addendum to the NEC, it's up the the inspector to decide what "the point closest to where the service entrance conductors enter the building".
Cliff
Well if it isn't in the NEC, then it is in the Omaha code. It is a very specific rule and it is in writing. I just didn't remember where.If you haven't drawn blood today, you haven't done anything.