[rlboothco]

I need to move my main service panel about 20 feet. All of the branch feeder wires need to be longer to reach the new box. How do I extend them?

[RickJ]

When I have a bigger project like this that I've not done before I like to call a local electrician for "an estimate" - and watch him close and ask a lot of questions about how he'd go about it.

That gets me two things:
1. The "how to" end of it, and
2. A price on the labor to help me decide if it's worth my time to do it myself.

Remember, that besides the "feeders" you've got the main line to deal with. Im sure you can't use a junction box - so you'll probably be running new from the meter.

There are some good Electrical folk here and it's early yet. I think others will be along soon.

Good luck on your project!

[tkrussell]

Relocating the main panel is a job that really should be done by a professional. If a single family home in the USA, you may be allowed to do your own electrical work , providing you apply for a permit from the local building authority . The inspector will answer any question you have but will not tell you how to to the work.

If the panel has a main breaker in it, once it is relocated 20 feet, a main breaker will need to be installed at the meter location. Once a main breaker is located at the meter, the feeder from the main breaker to the panel will also need a fourth wire, called an equipment ground conductor, sized according to the rating of the main breaker, and this wire must be pulled along with the new feeder. Any junction box must be sized according the quantity and size of all wires.

For the main feeder, a simple method is the use an aluminum cable called SER, has the 2 hots,1 neutral, and 1 bare ground wire. However this cable cannot be used if the path will not expose the cable to physical damage. May need to install conduit, all depends on your situation.

The branch circuit cables can each be removed from the panel and spliced in a junction box. You can use one small box for each cable, or you can use a larger box for several cables. Each existing cable will splice in a box onto a new cable of the same size wire, or larger, and the new cable can extend to the new panel location.

Another method is to install a large conduit, from a large junction box that has the branch feeders , and pull in individual wires in the conduit to the panel. This method requires that derating of the circuits be considered, which depends on the amount of current carrying wires and the amp rating of each circuit.

You will also need to deal with the main grounding electrode conductor, the wire that may be in the panel now that goes to any ground rods, water lines, gas lines, or any other grounding electrodes or bonding of metal systems. These wires cannot be spliced using normal methods, only using an irreversible method, which a few exist but usually easier to install new wires long enough.

I mention grounding gas lines, this is required by code , however ONLY if your gas utility allows this. Water lines into the building either will be used as grounding electrode, or must be bonded.

And if the main breaker gets relocated to the meter, the grounding wires now must go from the meter location and not the panel location.

I hope I have furnished enough general information that will cause you to hire a pro, or , if you are going to do yourself, begin researching the details to your situation. I believe that you will discover that merely asking a few questions will not cause you to know all the codes that are involved.

You may find that now may be the time to upgrade the size of your service, since you may be working up to an replacing the meter socket due to adding the main breaker there.

I used all the proper words used in the trade, not to confuse you, more to educate and to hopefully cause you to realize the job is not a DIY project unless you have the knowledge and training.

Do not hesitate to get back with any other questions.

[rlboothco]

Thank you for such a great detailed reply!
I have contracted an electrician to move the meter and install a main braker and run the main feeder to the servce panel at the new location .
My main question is how to properly extend the branch circuit wires. I have done a lot of elcetrical work (all with permits and inspections) and believe I can extend the branch circuits to the new service panel location myself.
So if I understand you correctly I can extend the circuits in the same way I would extend them in any other situation, meaning I can use a number of small junction boxes... or by using conduit and one large junction box... In the large junction box method you mentioned considering derating... What does derating mean?
Also is one method easier/safer/better than the other?

[tkrussell]

Not that you plan to do this, but the work you plan on doing will need it's own permit, cannot piggy back on the electricians permit.

The simplest method for you to do is to terminate each cable, now in the existing panel, into a 4"x4" junction box, have new enough cable and connectors of each type to run each individual to the new panel location. You can use #12-2 in place of any #14-2 and #12-2 you may have, and the same with using 1#12-3 in place of any $14-3 and #12-3 cables, and any other cables, #10-3 for dryer or water heater, and #8-3 for ranges, etc.

Have enough blank covers and wirenuts, and you can set up each box, perhaps on a long board on the wall or ceiling at the existing panel location.

If you tell me the type, quantity and size of each cable we can go from there, any other method besides the one I mention requires much more detail and calculations than you can do, I will run through here.