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leonard_voet · Dec 26, 2007, 07:24 PM

I've been looking for 2 days for an online wire gauge calculator.
I'm going to relocate my meter to the side of my house (converting from overhead to underground service), then I'm going to remove the existing electrical panel (from the outside of the house) and install a breaker panel on the inside of the house, opposite of where the original service panel was located.

I need to know what gauge wire to run from the new meter to the new panel
200 Amp Service
30 foot run

tkrussell · Dec 27, 2007, 05:34 AM

A residential 200 amp service can use a minimum of #2/0 copper or #4/0 aluminum wire.

There is no on line calculator that I know of, due to so many variables.

Keep in mind, the conductors feeding the meter, and the meter itself, needs to be rated 200 amps.

If the Main breaker will be in the panel, then use 3 wires from the meter to panel, if the Main is at the meter, then 4 wires are needed, the fourth being the equipment ground, which can be either a #6 copper or a #4 aluminum.

leonard_voet · Dec 27, 2007, 08:33 AM

Originally Posted by tkrussell

A residential 200 amp service can use a minimum of #2/0 copper or #4/0 aluminum wire.

There is no on line calculator that I know of, due to so many variables.

Keep in mind, the conductors feeding the meter, and the meter itself, needs to be rated 200 amps.

If the Main breaker will be in the panel, then use 3 wires from the meter to panel, if the Main is at the meter, then 4 wires are needed, the fourth being the equipment ground, which can be either a #6 copper or a #4 aluminum.

Thanks - I was thinking of running #4/0 copper, just to be safe.
One more question - Do I need to run the wires through conduit from the meter to the panel, if the wires are going to be in the attic?
Also - I already have a uffer ground in the existing panel. Is there a reason why I cannot run the ground from the new meter (with a main) to the existing panel and tap into that uffer ground or do I need to run a new uffer ground?

tkrussell · Dec 27, 2007, 04:33 PM

If you can afford to pay for more copper than needed, I have no problem with that. Exceeding the code is fine, and recommended.

Depends on what kind of wire your familiar with. If this is a multi-wire cable, such as SER, then no conduit will be needed unless it can be damaged.

If your planning on using something like THHN/THWN, or XHHW, individual wires, then a complete conduit system is needed, with all the fittings, locknuts, etc. so the entire run of wire is enclosed in raceway from box to box.

Your existing ufer ground system will be fine, From the neutral lug in the main switch run #4 copper to the ufer tail, and use a irreversible connection to join both wires. This can be a compression connector.

leonard_voet · Dec 27, 2007, 10:05 PM

Originally Posted by tkrussell

If you can afford to pay for more copper than needed, I have no problem with that. Exceeding the code is fine, and recommended.

Depends on what kind of wire your familiar with. If this is a multi-wire cable, such as SER, then no conduit will be needed unless it can be damaged.

If your planning on using something like THHN/THWN, or XHHW, individual wires, then a complete conduit system is needed, with all the fittings, locknuts, etc. so the entire run of wire is enclosed in raceway from box to box.

Your existing ufer ground system will be fine, From the neutral lug in the main switch run #4 copper to the ufer tail, and use a irreversible connection to join both wires. This can be a compression connector.

Thanks so much for the info.
If you need any automotive advice, hollar. I'm a ASE Master Auto and ASE Master HD truck Technician with 30 yrs experience.

tkrussell · Dec 28, 2007, 03:00 PM

Thanks for the offer, but at my age, I don't work on vehicles at all, period. What with all the computers and electronics in my Explorer, I know my limits, and will hire a pro for any work needed, short of changing light bulbs, filters, and air in the tire.

My wife lets me drive it once a week, so I can get it cleaned and LOF when due.

I will say, you kind of concerned me when asking if conduit is needed for the wires to the panel. What did you decide to do?

leonard_voet · Dec 28, 2007, 06:36 PM

Originally Posted by tkrussell

Thanx for the offer, but at my age, I don't work on vehicles at all, period. What with all the computers and electronics in my Explorer, I know my limits, and will hire a pro for any work needed, short of changing light bulbs, filters, and air in the tire.

My wife lets me drive it once a week, so I can get it cleaned and LOF when due.

I will say, you kind of concerned me when asking if conduit is needed for the wires to the panel. What did you decide to do?

I bought 3 25' sections of #3/0 and 25' #6 bare copper.

I'm going to come into the new 200A Cutler-Hammer ranch panel underground (c/o local utility company) via 2" conduit.
Thru the meter and to the 200A main. The main feeds a set of lugs and 8 breaker spaces.
From the lugs, I'll run the #3/0 out the top of the panel and into 2" conduit up to the eaves.
I'll punch a hole in the eaves and turn the conduit into the attic via a 2" LB Access.
I'll run 2" conduit sitting on top of the rafters to another 2" LB and run the wire down the wall, through the wall top. Once I am in the wall, I'll not need to use conduit.
I'll then come into the new 200 AMP distribution panel (which is opposite of the original panel on the outside of the house).

Once I do this, I can have the local util company come and run a new service line from the pole, to my ranch panel.

Tomorrow, I'm renting a ditch witch to dig the 60'x3' trench for the new service line.
Monday, the util company is coming out to inspect the ditch - once they OK the ditch and conduit, I can fill the trench in and start working on the wiring.

I'm REALLY not looking forward to pulling 3 strands of #3/0 wire, 25' through conduit, laying on my belly in the attic. I'm going to try pulling from the attic to the eaves, which should make it a little easier.

tkrussell · Dec 28, 2007, 09:08 PM

No, no, no, do you really mean: "Once I am in the wall, I'll not need to use conduit.".

This is not proper, do not do this.

As I stated before, the conduit system must be a complete run, using connectors and locknuts, from BOX TO BOX.

If you do what you stated, you have violated so many codes, and standard installation practices, your home will be a model of what not to do.

If you do what you stated, get it inspected by the local inspector see what he has to say, and be ready to rip it out and redo it.