New Breaker box

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  #1  
Old 11-28-00, 10:30 AM
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Question

I'm replacing an old 60amp box with a 150 or 200 amp box. My question is what size wire should be used to connect it to the meter can and run up the weather head?

Thanks!
 
  #2  
Old 11-28-00, 10:39 AM
J
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2/0 Aluminum SE cable for 150 amps, 4/0 aluminum for 200 amps. I recently did the exact same job at my house, and passed inspection! So feel free to ask further questions as they arise.

JH
 
  #3  
Old 11-28-00, 01:56 PM
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More questions...

OK JH here goes...

What does the 4/0 aluminum for 200 amps look like? 2 shielded cables and one bare?

What does the 4 and 0 stand for?

How is the 2/0 different from the 4/0 al se cable?

Any differences that I should know about between using a 150 or 200 breaker box?

How difficult is wiring the meter can?

Would you use plastic or metal conduit for the weatherhead?

Background: I've got an old house (1905) that has wiring that SCARES me. My goal is to setup a new 200 amp breaker from the weather head to the breaker box then call the power co and have them hook up the meter and attach to the weatherhead then I'll start running new circuts.

Does this sound reasonable? Any other details you could elaborate on would be fine by me.

Thanks for responding!
 
  #4  
Old 11-28-00, 03:06 PM
J
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Hi Still,

Type SE cable looks kind of like romex on steroids. 2/0 is about an inch by 1-1/2" flat oval. And pretty hard to bend! Add about 1/4" to both dimensions for 4/0. SE cable consists of two insulated hot conductors wrapped with a stranded, flattened neutral.

SE cable has no ground, you provide that with an 8' ground rod. My utility requires two rods. NEC says that if you have more than one they must be 6' apart. I went 7'. You run a #6 bare copper from the grounding lug in your new panel outside, through the clamps on both rods, then back into the building back to your grounding lug in one continuous loop. Then run a #6 to your plumbing, connecting within 5' of the water main's entrance to the building and jumper around the meter with the same piece.

I recommend checking with your utility for their requirements. Mine is fussy! They often will not provide you with a disconnect/re-connect service call unless the job is up to their specifications, which they will give you in advance, and that the job gets an inspection passed. I contacted my local municipality, got the permit ($15) and inspection application ($40) and went to work. I am not an electrician, which was not a requirement in my area anyway, but I had copies of the NEC and utility specs, have a lot of electrical experience from various jobs, and spent a lot of time reading. I was also able to consult with the inspector and my utility rep for guidance, both of whom were very willing and very helpful.

2/0 and 4/0 are just trade sizes. You may be familiar with wire gauge such as #14, the smallest allowed for home wiring. The size gets bigger as the number gets smaller till you get to 0. Then it goes 1/0, 2/0 etc. Our system is wierd. Once you get to 4/0 we go metric, in kcmil (thousand circular mils) starting with 250.

2/0 and 4/0 differ only in conductor size, which translates to current carrying capacity.

Difference between 150 amps and 200 is less than a couple hundred bucks over the whole job. If you have total electric heat, hot water, range, central air 200 should be adequate, but to be precise the NEC has a set of calculations you must do to figure out the proper service size for your home. If you don't have electric heat & hot water or a huge house 150 should be more than adequate, generally speaking.

The meter can is a piece of cake. Take the cover off one at your local home center and look, you'll get it right away.

For the weatherhead you usually don't use conduit. It's a complete assembly with a hood, 3 holes for your individual conductors going to the utility's aerial, and a built-in "romex" style clamp to restrain your cable. You just run the cable flat to the outside wall of your house from there.

You said you'd "set up a new 200 amp breaker" from the weatherhead to the breaker box. Was that a mis-print?
For mine I installed the weatherhead and SE cable next to my old ones, installed the meter can and ran the cable inside to my new panel, which I mounted next to my old panel. Then transferring everything over took very little time when the utility co. came for the cut-off.

One further advantage I gave myself: the old fuse box has two "sub-feed lugs" at the bottom for adding additional load. I pulled the main fuses and installed #2 copper jumpers from there to the main lugs in the new panel, essentially running the whole thing off the old panel. Then I started transferring my individual circuits a few at a time evenings and weekends, with the mains off in both panels, at my own pace.

I'll check back in with you tomorrow and see what ya think.

Later, JH
 
  #5  
Old 11-28-00, 03:50 PM
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Talking

Sorry, I wasn't clear with "set up a new 200 amp breaker from the weatherhead to the breaker box"

It was supposed to be, well...

"For mine I installed the weatherhead and SE cable next to my old ones, installed the meter can and ran the cable inside to my new panel, which I mounted next to my old panel." JH

...yeah, what he said!

I also used the wrong term (conduit) for the pipe part of the weatherhead. I've seen what looks like plastic ones at Lowes and Home Depot. Was wondering (unless I saw wrong) which might be better, metal or plastic?

I'm assuming the utility co will actually connect the wires to my new ones that I'll leave hanging out the top of the weatherhead about 2 foot?

Very informative JH! I bow to your high exalted poohbahship of electrical knowledge!
 
  #6  
Old 11-29-00, 06:50 AM
J
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I appreciate your high compliment, but please try to hold back a little on the "exhalted" stuff. We all have different experiences, and I'm certainly happy to share mine. And I feel we are all still in the process of learning. I tend to think alot more about all I DON'T know than all I do. There are certainly wiser people in here than I, in my opinion.

As far as the weatherhead, I got mine from my local electrical supply house. It was a kind of aluminum alloy and seemed kinda cheesy. I expected something alot more beefy, but it certainly does the job just fine, and that's what they hand electricians every day, so I guess it's fine. I haven't checked out the PVC models, or even seen any that come with pipe. I'd offer a guess that those might be intended to affix to conduit. Mine had an SE cable clamp, as I described previously, and the three individual conductors pulled through the holes provided.

And you are correct, only the utility can cut in your new conductors. Mine requires 24" excess be left extending from the weatherhead. I went with 36". And man, I can't say enough about buying too much wire. You can measure off your needs three times, come up with the same figure to within a milimeter all three times, and when you go to install the stuff somehow you're 4 feet short and NOW whaddaya do??? I have about 12 feet of leftover SE cable sitting in my garage right now. Probably be sitting there for the next 20 years, but I have no regrets, it was money well spent!

As you progress through this project keep in touch with us, there are a couple electrical inspectors who hang around here and are very helpful and wise. Also a couple very sharp electricians. See ya later.

JH
 
  #7  
Old 11-29-00, 06:41 PM
Wgoodrich
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What Juicehead said is mostly right if you are high enough. The NEC requires you to be a minimum of 10' above finished grade if you are not able to run a vehicle under the service drop. 12' if across a driveway or aree a vehicle can drive under the service drop. 18' if the service drop is over a street or alley. A service drop is that last wire suspended in air, coming from the utility pole and your home. The measurements above are from finished grade and the drip loop coming out of the weatherhead to be connected to the utility company's service drop. The measurement must be measured at its lowest point of the drip loop.

Also the 2/0 al is not mentioned right by Juicehead.

The following is the proper minimum wire sizes for 100 amp and 200 amp services.

# 2 Al. or # 4 Cu. is the minimum wire size for a 100 amp service designed in a dwelling.

4/0 Al. or 2/0 Cu. is the minimum wire size for a 200 amp service designed in a dwelling.

The NEC article number is 310-15-B-6

Now if you have to go through the roof and the conduit service riser is supporting the utility service drop in the air, then you should use a 2" Rigid steel or 2" IMC Rigid aluminum conduit going through the roof. A maximum of 30" is allowed to reach above the roof without guy wire supports. The riser must be supported at least twice by mounting clamps to the dwellings wall. Don't forget to use a rubber roof boot to seal the roof if passing through the roof.

Now if the minimum heighth is reached without running through the roof then you can use the type SE cable mentioned in Juicehead's reply or PVC Sch 40 or 80, Emt, or even more choices.

The meterbase is required in my area to be 5'6" to center of meterbase. This is a utility company rule. The maximum height is 6'6" to the main breaker in the panel and must be out of reach of small children for the lowest breaker in the box. The service panel must not be installed in a bathroom or clothes closet. The panel must have a dedicated wall space of 30" wide and must have a clear approach of 36" in new or 30" if remodle work. The main overcurrent device [breaker or fuse] must be either outside or nearest point of entrance to the building inside. This last statement can give you a distance allowance of almost any distance. This distance is ruled by the authority having jurisdiction [electrical inspector]

Before you do anything contact your local Building Official and serving Utility Company !

This should get you a good start.

More to come when you have more questions

Wg
 
  #8  
Old 11-30-00, 07:46 AM
J
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WG, I stand by my 2/0. 310-15(b)(6) specifies this size for 150 amps. Additionally, this is my setup exactly, which I just did this spring and passed inspection, so I'm doubly sure. You mentioned 100 amps, which was not discussed in this thread.

Still-Learning, when wg mentioned your main overcurrent device being at the "nearest point of entrance to the building" inside he was quoting the NEC. They don't give a quantitative distance. I'd like to add a little to this. First, that point is where your SE cable pokes through the exterior wall and enters your house. I believe the NEC doesn't want a substantial length of unprotected cable traveling across the interior of your home. With your main disconnect as close as possible, if anyone were to whack your cable with a shovel and cut through the insulation your main breaker or fuse, being upstream, would cut the power instantaneously, preventing fire or injury. That's my take on it anyway.

But I was told by my utility that inspectors "like to see 5 to 7 feet". One of the guys in here who's an inspector in a different state says he requires 5 feet in his jurisdiction. I'd go with 5. The main overcurrent device, by the way, is the first disconnect your service sees after the meter. It can be the main breaker in your new panel, or a separate enclosed breaker or fused switch. In my case, the old fusebox was in the center of the house with the meter above it. My utility requires the meter to be moved outdoors if upgrading, and THEY specify where you have to locate it. Since I have a large front porch in front they said I had to locate it on the side of the house - 20 feet away! (At MY expense, of course.) This meant I either had to extend every circuit in the house 20 feet from it's previous termination point (the old fusebox) or I had to by a separate main disconnect and locate it within the 5 feet, then run more 2/0 cable to the new paanel. I bought a 200 amp fused switch and installed it 5 feet from the point of entrance. Expensive little bugger, too!

If you run into this situation you will need to know special requirements for connecting your grounds & neutrals.

Hope that helps.

JH
 
  #9  
Old 11-30-00, 08:05 PM
Wgoodrich
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Sorry JuiceHead, eye sight failing or brain on vacation. I read 100 or 200. You are right on the wire size for 150 amp.

You have my opologies. I will promptly beat myself with a wet noodle but only one strike. I am a wimp ya know. Can't stand pain, or too old to try.

Sorry my mistake

Wg
 
  #10  
Old 12-01-00, 11:09 AM
J
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WG, no need for apology, please. I figured that you read 100 or 200, and never felt as if you were shooting down my answer. But this is one of the great things about this joint, we all check each other's work and the poster benefits. I have certainly been incorrect in here in the past, and I'm honored to have you watching my back when I do again.

Now put away that wet noodle!

JH
 
 

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