Planning electrical upgrades to new home purchase

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Old 10-04-12, 10:54 AM
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Planning electrical upgrades to new home purchase

Hi all, new forum member here. Thanks in advance for your replies! My wife and I just bought our first home, a 1955 house in Contra Costa County, California with a Federal Pacific panel and 2-wire cable without ground. It has an old fuse subpanel in a closet (definitely not to current code) and a second subpanel for an addition done by the previous owners. We want to replace the main panel and the fuse subpanel and to upgrade the place for arc fault and ground fault protection where reasonable. We had an electrical contractor out who made some recommendations, but he was sort of an "I'll bill you the bottom line and you let me handle it" guy, and I really want to know what's going on and perhaps get my hands dirty where it's safe to do so. His recommendations also seemed a little over the top, which is why I'm coming here. I am a research chemist by trade, so I don't have much experience with electrical work (beyond wiring up temperature controllers, etc), but I'd love to learn. I have some questions to get myself calibrated, and I'll be very grateful for any responses!

1. The electrical contractor said we'll have to rewire any circuits we want to have AFCI on. I don't know how the house is wired, but is it a guarantee that 2-wire will have a shared neutral? Or is there some other issue he was worried about?
2. Should we rewire the house for safety reasons anyway, independent of the AFCI issue?
3. He recommended we pull a permit to increase the 100 A main panel to 200 A. The house is 3-4 BR (depending on how you count) with forced air heating, no AC, electrical dryer and stove (on 240 V), and no other major appliances. I feel like with some planning we would be fine on 100 A. Am I fooling myself?
4. He recommended we replace the fuse subpanel with a 30/40 pole subpanel at 100 A (obv assuming 200 A main). I can't imagine we would need that many circuits. Does that even make sense on 100 A?

I think I'll start there, as the rest of the plans sort of depend on how we set up the panels and wiring. I appreciate any advice on this, especially as to whether the recommendations are reasonable. Thanks in advance!

David
 
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Old 10-04-12, 11:21 AM
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If the house has 2 wire wiring, this upgrade is a big deal. While coming into the house, ground and neutral are the same, they need to be separate wires everywhere past the initial electrical panel. Whether you need 200 AMP service depends on what elecrtical items you have. A/C and electriic heat are the largest users, but electrical dryers, stove, hot water heater if present can also significantly up the load. It seems that more and more ways of using electricity keep turning up. If the line coming into the house needs to be upgraded, that is the biggest cost. Electrical panel costs are trivial compared to the labor of this job so I would go with the 200AMP panel. Other than initial installation cost, there is absolutely no downside to the bigger panel and it provides you with more flexibility in the future whether it be appliance choices or eventually an electric car. If it were me personally, I would have the electrician replace the main panel and I would do everything else. But that requires knowing electrical code issues. Having a home that outdated, all accessible wiring should be replaced with three wire or 4 wire romex cable (except in Chicago where Romex cable is not recognized by building codes!). 4 wire for 220V circuits and 3 way light switches (2 switches in same house can affect same electrical item). GFCI can not work unless there is a separate ground and neutral wire to the outlet. Electrical codes require ground (not neutral) wires to connect to every metal junction box. Plastic boxes can skip this step. The big dilemma is ripping up walls and ceilings. Proper wiring discourages splices in the wire (which all should be in junction boxes if used). Any circuits that can be completed in an unfinished basement should be replaced, but those outlets with inaccessible wiring in walls and ceilings probably should be left alone unless there is a specific need to replace or you are ripping up walls for other purposes (e.g. kitchen remodel).
 
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Old 10-04-12, 11:33 AM
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Welcome to the forums!

He recommended we pull a permit to increase the 100 A main panel to 200 A.
A 200A service would be a good investment if you foresee ever adding central air. Otherwise 100A may serve you well. You will need to do a residential load calculation to fully determine that. A 200A service, BTW, should cost only pennies more than a 100A service to install.

is it a guarantee that 2-wire will have a shared neutral?
No. It is a guarantee that that there is no EGC - equipment grounding conductor, or ground wire - running with the branch circuits.

Should we rewire the house for safety reasons anyway, independent of the AFCI issue?
Yes. The ground conductor has been required for new construction and major remodels for several decades. It is an important safety feature.

He recommended we replace the fuse subpanel with a 30/40 pole subpanel at 100 A (obv assuming 200 A main). I can't imagine we would need that many circuits.
I can't imagine that you would need more circuits than the 40 available in one main panel. Do you actually need any subpanels?

How is the water heater powered? What is the heat source for your forced air heating? Do you have gas available?
 
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Old 10-04-12, 02:30 PM
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Another reason to consider a service upgrade is if the service entry wires (the wires from the weatherhead at the roof down through the meter to the panel) are old, frayed, or looking like they need replacing. Now would be a good time to do it.

What a lot of people do when moving into a house with old wiring is to upgrade it a bit at a time. Start off with a new main panel, then circuit by circuit run new wires, new fixtures, all back to the main panel. You could probably keep the old fused subpanel for a while while you upgrade and replace those circuits. Then eventually remove it completely.

I agree with Nashkat, unless your house is especially large or spread out, I would consider whether you really need that subpanel. An extra 20' or so of wire is worth it to keep all your electrical disconnects in one place IMO.
 
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Old 10-04-12, 05:27 PM
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I would also start with a complete service upgrade and probably would also go with a 200 amp service. You may not need any subpanels depending on the layout of the house. You can buy a 200 amp main breaker panel with as many as 60 circuits (not at the big box) from most supply houses, although they may not stock them. I think both Cutler-Hammer and Siemens make them. The main thing though is, definitely get rid of the old Federal Pacific panel first! You can go ahead with this step as you plan the rest of your rewire. You do not need a grounding conductor for GFCI protection, but it would be better and safer if you had grounding conductors. If you have shared neutrals on any circuits, those circuit cannot be AFCI protected.
 
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Old 10-04-12, 11:35 PM
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Thanks for the replies! It's great to hear a several opinions. The wire to the house is 100 A now, but perhaps that will just have to be upgraded. I definitely appreciate the difficulty in predicting future electricity use. I also like the idea of eliminating the subpanels. I think we'll go ahead with the new panel and continue with the rest of the job as I can.

In the meantime, is there a resource you guys recommend that I read before embarking on a first home wiring job? Before I get into the local code I feel like I need a more general primer. I'm embarrassed to say some of the terminology is still foreign to me, though the concepts are typically quite clear once I know what I'm reading.

Thanks again!
David
 
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Old 10-05-12, 01:04 AM
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Wiring Simplified is the best single book a beginner can read. It not only cites code but tells you WHY the code is as it is. The cost is less than $10 and it is available through many on-line sellers and also is usually available in the electrical aisle (not the book and magazine section) of the major home improvement mega-marts.
 
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Old 10-05-12, 02:44 PM
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I of course agree with Furd's suggestion of Wiring Simplified, though I would also personally recommend "Wiring a House" by Rex Cauldwell. For me, this book solidified a lot of questions I had. He also talks a lot about the 'above code' house. Things you should do (or at least consider) when planning your jobs to make living in your house easier.
 
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Old 10-05-12, 05:42 PM
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The wire to the house is 100 A now, but perhaps that will just have to be upgraded.
If you mean the overhead drop from the power companies pole to your house, don't worry about it. Typically the power company will upgrade that for you as required by your load. If you will be adding loads, you may have to submit a load sheet to them.
 
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