# Old House Rewire



## s_anthony (Jan 3, 2009)

I'm not an electrician, so I can't preach code at you, but I thought with a rewire you were required to run 20amp circuts for electrical outlets (maybe I'm thinking kitchen). I thought 15amps were for light circuts...

Even if not, I would take the extra time and effort as I would assume this would raise the resell value of the house... 

Sorry I can't be of much help other than a bump really.. I'm slowly working on my own projects and that takes enough time to research them on their own


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## Gigs (Oct 26, 2008)

1. I prefer 20 for outlets and 15 for lighting but it's far from a universal preference. A few outlet circuits are required to be 20 but the rest can be 15. If you want 15 then do 15.
2. You are correct that it violates a few code parts to strip the jacket off romex and use the wires as if they were THHN. If you want to do it anyway, call your inspector first and ask him if it's OK.
3. You can install junction boxes anywhere in existing circuits to tap off of them. Don't extend ungrounded 2 wire circuits, just replace all those.
4. Both plastic and metal boxes are fine. All the metal parts need to be bonded together, the only way to get in trouble is if you somehow isolate part of a metal conduit system by using plastic boxes.


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## J. V. (Jun 1, 2007)

finnimus said:


> Here’s what I would like to do:
> 
> 
> Install a true 100 amp main panel and treat the existing panels as sub panels of the new main. This would give me the ability to shut off power to the house from one location. This would be done by an electrician.
> ...


This is not a project for the average DIY'er. I highly recommend you get proffesional help. There are so many things to consider, and a journeyman considers them every day. I would think real hard on this.
Have you pulled a permit yet? You need one. The inspector can then give you instructions as to how the jurisdiction requires this work to be performed. 
If you decide to go forward you can always come back here for extra help. I know you will need it. I am not saying you cannot do this job. I just think some assistance from a professional would be an excellent idea. Good luck......John


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## finnimus (Jan 3, 2009)

Thanks to everyone for your help so far, especially J.V. (John). I'd like to address some of your comments:

"I would make the existing service a 200 amp lug panel. Then use smaller sub panels as needed. Use a meter main type panel outside. This will be your disconnect for the whole house. In addition it will give you some extra breakers outside for future use."

I never thought of a meter main type panel outside. It's not something I've seen used in many residences in this area. What's the cost of this vs. a traditional panel? 

"If you must have the 200 amp panel in the garage, why not make this panel the main panel? If it were me this garage panel would be a 100 amp sub or a 200 amp main."

I do intend to make this the main panel once all the circuits are moved. The only reason why there's a panel in the garage now is because the old owners ran out of space on the "main" panel outside. Other than that, there's no real need for a sub-panel in the garage (unless someone here convinces me that it's a good idea). Just for right now, the 200 amp will be used as a sub while the circuits are being transferred over. The reason why I picked the garage for the location of a new panel is that I have found 2 areas where I can create a wiring chase to take new circuits up to the 2nd floor and attic. 

"If you upgrade the 100 amp main to a 200 amp main you will not have to move existing cables. While there are no code violations regarding feeding a 200 amp panel from a 100 amp panel, doesn't it make sense to have the larger panel feeding the smaller panels. 
200 amps is the norm for most residential applications. 

The current wires are not in good shape, so I'm afraid we'll end up changing everything out regardless of what location we use. Given that, it's much easier to run new wires from the garage than it is from the current panel location. In the old location, we would be able to change out existing wires, but new circuits would be a lot more time consuming. It makes complete sense to have a larger panel feeding smaller panels, that's why the current 100 amp "main" will only feed the new 200 amp panel for a few months. After that, the setup will effectively be a shutoff feeding the 200 amp panel. I can easily upgrade my main panel to support 200 amps, but I need to have the service upgraded and that's something that I don't think I need right now (and I really can't afford it). 

When you say: "What I mean is why stay with 100 amp when you can easily go to 200 amp. You will have to change it out anyway, right?" Do you mean the panel, the service, or both?

"By using a meter main outside as your service you get the main for the whole house, plus some additional circuits for outside. A 200 amp meter main consists of a meter base, 200 amp disconnect and some extra breaker slots for outside, all in one enclosure. "

Thanks for giving me this idea, I'm going to start looking into it. 

Based on your advice, I'm going to run 12/2 and 20 amp breakers for the general electrical and lighting circuits. The special stuff (dryer, hot water heater, etc.) will have their respective amperage breakers as well. 

Also based on your advice, I am going to run THHN through the conduit and NM Cable for new outlets. I would say that 85% of the house is in conduit. I've been told that you can have at most 3 90 degree bends and still be able to pull wire. Did they follow that rule in these old houses? If the wires were not in conduit, I'd be much more reluctant to take this on. The areas that are not in conduit are the kitchen and half of the garage. Old homeowners did their own wiring in these areas. That wiring will be heavily inspected if not changed out. All of my outlets in the kitchen are wired hot neutral reverse and we've even found a lighting fixture wired backwards. That makes me worried about the work behind the walls. Luckily, the wiring in the garage is exposed and the wiring in the kitchen will be exposed during a remodel. 

I have not pulled a permit yet or gone through the process of finding out how to get one. I only want to go through all that trouble if I decide to take this on myself. Otherwise, I'll leave all the permit pulling to my electrician. :thumbup:

Speaking of permits, what's the tipping point for pulling a permit? Rewiring the house? Installing a new panel? 

Also a question about the areas for a wiring chase I've found in the garage. One uses a wall shared by a bathroom and a hallway. There is no plumbing running through this wall and there is no threat of water getting behind it. The other area is behind the back wall of the bathtub. Granted we'll have tile, backerboard, and plywood, but there is a small but unlikely chance that water will enter this area. Does this change the type of wiring / protection I will need?

Thanks again for all of your (everyone) help so far. I appreciate the time you have taken to reply to my posts.


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## Billy_Bob (Sep 11, 2008)

When rewiring a house, it is not much more expensive to go with 200 amps instead of 100 amps. And not much more expensive to go with 20 amp circuits than 15 amp circuits.

There are many things which use a lot of wattage (amperage). And when you have regular things on the circuit, then add a high wattage appliance like a vacuum cleaner, the breaker trips if it is only 15 amps.

Then anything which produces heat is a high wattage appliance. Space heaters, hair dryers, kitchen appliances like deep fryer, warming plate, microwave, waffle iron, etc.

Then for outside/garage outlets, you might get an air compressor or shop power tools which are high amperage. If you have one circuit for the garage and have a freezer out there, then also run a compressor, the breaker is going to trip with them both running.

Then you might want a window air conditioner or two and want dedicated 20 amp or more circuits for these.

I've lived in homes with all 15 amp breakers and had frequent problems with breakers tripping. Now my house has all 20 amp circuits and I never have a breaker trip.

Here on page 3 is a list of what amperage some appliances use...
http://rveducation101.com/articles/RVConverters.pdf


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## Billy_Bob (Sep 11, 2008)

P.S. Most things list the wattage. Here are a few calculators to convert wattage to amps or the other way around. Use those under "Single Phase"...

http://www.jobsite-generators.com/power_calculators.html


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## finnimus (Jan 3, 2009)

Bill Bob, thanks for your reply. It looks like we were replying at the same time. I agree with the advice presented here and will run 20 amp circuits through the whole house for general electrical and lighting. 

I'm trying to build the infrastructure for 200 amps. The only things that won't support 200 amps in my current plan are the shutoff and the service to the house. Those will probably change in the future when we get some of the other priorities out of the way. Then again, if I call the electrician out to replace/ install the panels and can save money on service calls and various other fees, I might just have it done at that time.


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## Billy_Bob (Sep 11, 2008)

When you start replacing panels and the like, you may be required to bring your main electrical service up to code. And it is less expensive to get an electrician out once than twice. Then not much more for a 200 amp panel. Check the prices at the store.

I like the 200 amp meter main idea.

Then when owning a house, it can be a money drain! I tend to want to put stuff off due to the high cost. But actually I'm glad I did a lot of stuff years ago. The cost these days is double or triple what it was when I did these things. So factor in that the cost will be higher in the future.


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## finnimus (Jan 3, 2009)

Thanks for your additional advice. We're in a frustrating situation here. We purchased this house because it was in better condition than other houses we looked at. Turns out that it had a lot of problems that didn't come up in inspection and the seller did not mention. However, there's no concrete way to prove the previous owner knew about some of the issues so we have no recourse. 

If I were to hire an electrician, how long would the job take? We're in 1400 square feet. 10 Lights, and about 12 outlets, mostly in conduits. There's only 1 3 way switch in the entire house.


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## jamiedolan (Sep 2, 2008)

finnimus said:


> Thanks for your additional advice. We're in a frustrating situation here. We purchased this house because it was in better condition than other houses we looked at. Turns out that it had a lot of problems that didn't come up in inspection and the seller did not mention. However, there's no concrete way to prove the previous owner knew about some of the issues so we have no recourse.
> 
> If I were to hire an electrician, how long would the job take? We're in 1400 square feet. 10 Lights, and about 12 outlets, mostly in conduits. There's only 1 3 way switch in the entire house.


What kind of conduits? Can you post some pictures? of the panels, meter, and the conduits?

Jamie


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## Leah Frances (Jan 13, 2008)

finnimus said:


> I have not pulled a permit yet or gone through the process of finding out how to get one. I only want to go through all that trouble if I decide to take this on myself. Otherwise, I'll leave all the permit pulling to my electrician. [/COLOR][/COLOR]:thumbup:
> 
> Speaking of permits, what's the tipping point for pulling a permit? Rewiring the house? Installing a new panel?


The best person to answer this question is your local permit office. Some areas require a permit for anything other than a 'repair' some are more liberal - Only your permit office can tell you what your requirements are.


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## finnimus (Jan 3, 2009)

jamiedolan said:


> What kind of conduits? Can you post some pictures? of the panels, meter, and the conduits?
> 
> Jamie


Jamie,

Here are 3 images of the main panel, the first sub panel, and the outside entrance of the service wire into the garage for the 3rd panel. I can't find my camera at this moment to post pictures of the conduit and the other panel, but will do so as soon as I can. 

Thanks.


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## archsteve (Jan 16, 2010)

Your situation sounds very similar to ours. We are going to a complete remodel of an adobe/concrete home. There is very little crawl space in the attic, and no real crawl space under the floor. We need to reground our panel, and run conduit throughout the house. 

How much did your rewiring job cost you for the 1200 sq. ft. home?


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## UTremodeler (Feb 3, 2010)

finnimus, I also have been exploring the idea of rewiring my house. Surprisingly, we have many things in common about our homes (1930's house around 1400-1500 sqft) and electrical situations (old conduit wiring). I have already done much of the moving around of breaker panels via a licensed electrician. I have a detached garage which is where I moved the meter and service entrance to. I bumped up my amp service to 200 at the garage with a 100 amp subpanel for garage power and 150 amp single breaker for the house. From the garage I ran cable to the house via underground conduit to a 150 amp subpanel, which is where I stopped the work a few years ago.
Recently, I have been replacing the insulation in my attic and realized the poor condition of the wiring and how badly it needs to be replaced. Based on your posts I have few questions and maybe some advice; hopefully we can help each other out a little. You mentioned that you were planning to pull most of the old conductors out of the old armored cabling and replace with THHN, which is definitely the cheaper way to go. However, it seems to me that this would be a very difficult task and have found other chat boards that suggest the same thing. One of the other posters suggested that this would be easy, but I wonder if they thought you had conduit instead of the old armored cable. Just for clarity I have posted a pic of what I mean by armored cable. Is this the type of wiring you have? Usually the conductors in the cable are insulated with a brittle plastic (which is now crumbling off) and a cloth sheathing over that. I've been thinking of replacing all the armored cable with 12/2 romex. In most cases where the cable drops into the walls I believe I can just pull out the cable and pull in the romex at the same time as the cable is not stapled down. Have you done any investigating to see if this is the case at your house? In some cases I do expect to leave the old cabling in the walls and fish in new romex, which I don't expect to be to difficult because I know my house doesn't have insulation or cross braces in the walls. In addition, the metal receptacle boxes are easily removed because they are not nailed to studs, but simple nailed to the walls which are wood planks instead of sheet rock. Is any of this similar to your house?


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## milton68 (May 14, 2011)

now I see you posted a year ago but hopfuly you are still active in your pursuit of a home rewire. I too am doing a 30's home and of course there are similarities. What you have pictured is the armored cable and I believe you are correct in that we can not pull new wire through it. Did you ever rewire your home, and how difficult was it to pull out the cable?


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